Weak knowledge of audio and video: February 2011

Tuesday, February 22, 2011

【 Weak current College 】 broadband network development will enable media streaming into the future of mainstream technology---Power By 【 China power house network 】

Competition in the broadband network will eventually be broadband applications competition, thus was born the medium speed network based streaming media (StreamingMedia) technology is increasingly affected by the people's attention. It promotes the Internet overall framework of innovation, changing the traditional Internet empty content representation, empowerment of broadband applications more entertaining and interactive, will become the mainstream of future broadband network technology. Before Microsoft, SI, via and Hangzhou China Netcom manufacturers in Hangzhou, jointly hosted a field about streaming media technology and operational policy of the Forum again came the surprising information – streaming media, reach of golden apples. Streaming media should broadband and NASDAQ stock index reported from 5000 points, people's mood plunge from the clouds ... The Internet bubble broken, broadband network began its long journey. In the early stages of the construction of broadband networks, telcos from heavyweight to real estate developers are joining to the intent to change the Chinese people living in the information system. But people come to realize that in this field in the Battel, broadband applications is the real master, so people have been looking for a suitable broadband network application supporting technology. We know, from the network on the first picture, and now all forms of Internet video, animation, audio and visual perception sensory networks get great satisfaction. While it is facing another inevitable embarrassment: precisely because it needs constant improvement and online population continues to increase, coupled with the limitations of the network hardware device, making the file size becomes the network transmission in a parameter to be ignored. On the one hand, people want to be seen on the network media demonstrates vividly clear, on the other hand people have to face such a slow network speed file transfer the required amount of time. So the network based on medium speed of streaming media technology into people's perspective. Application based on streaming media has changed the traditional Internet empty content representation, have a strong visual impact of video programming into access to broadband networks is one of the most important applications. Like Ali Baba came into the hidden treasures of the cave. Thus, in Chinese broadband market, based on MPEG-1, MPEG-2, WMT, REAL, QUICKTIME all kinds of streaming media technology products has become the darling of the broadband network, here are some core coding for Chinese companies, which will undoubtedly stimulate the development of the broadband, also provides a Chinese products and foreign products fair competition arena. Follow the guidelines of streaming media technology, people see the future direction of development of broadband, multimedia interaction became the people on the future development of broadband networks. The broadband carriers, particularly heavyweight telecom operators that want to be able to stream media technology and the development of broadband networks, not only to consolidate the original network communication market, but also to intervene in the emerging online media and entertainment market since last year's revenue of telecommunications, telecommunications business growth (approximately 6 per cent) since the first time since 1984, is lower than the GDP growth (about 8 per cent), while the Chinese traditional cable TV industry as monthly charge only costs $ 10, but developed countries 1/15, the South American country of 1/10, market growth is considerable. Shenzhen CATV station change to network media market Outlook is promising. It is reported that now Shenzhen wired encrypted television fees more than 20 000 users. 140 Yuan/month including TV with more than 10 foreign satellite programmes, as well as music, fashion, some specialty channels. HBO charges only one channel is 50 Yuan/month. Although traditional telecomcarriers themselves do not have the right to broadcast radio and television content, broadband network and stream media interaction and future development, allowing broadband telecom operators saw the development of the broadband interactive video opportunities and good prospects, and radio and television enterprises hope through DVB market mining upgrade traditional broadcast television market value, start of pay TV, interactive TV market. Analysis, a video media war is about to hit the market, and hidden in the media war under the surface is a contest between the media and technology. Experience market challenge broadband network, it was born in communication and network technology, it is a technical lead market demand of industry, but the key to success is the consumer market can not be accepted. Obviously, the streaming media technology as the main force, which will also face a harsh test of the market. In recent years, the streaming media technology in the world has been applied, in particular the 1995 launched the first Internet streaming media player, streaming media application with explosive growth. According to statistics, Internet weekly about 45000 hours of radio programs, 58 United States television provides Web broadcasting, 34 television provides on-demand services. Nearly half of multinational companies in the realization of internal use streaming Web radio. As a few years ago the IP network and Web technology, streaming media application is in a period of rapid growth. There is a set from a survey of international authority, last year in online access to streaming media increased 65%, Western network developed countries the number of access streaming media has reached 1.8 billion, accounting for about one-third of Internet users in Asia, but also rapidly increased to 35 million people, approximately 1/6 of the Internet. Echo user growth, last year the Internet video streaming technology increases up to 251 per cent. According to the forecast, to JupterCommunications 2004 year, streaming media market will render huge revenue potential, including income-generating consumer services will be $ 9 billion. This huge market is attracting more and more enterprises to participate in the competition. These data, description of streaming media technology-based broadband applications have a very big market potential. However, currently in the market in the process of transfer into revenue has encountered many problems. People think of PPV and have not succeeded, digitized media also encountered many Internet piracy, telecom operators can only be streaming media application packaged into numerous broadband applications to collect the monthly subscription fee and get a temporary settlement. However, the traditional pay television network has access to an unprecedented success. HBO and Cine max in the year 2000 the number of users only United States reached 3670 million. In a breakthrough in a applauded emergence amid streaming media technology encountered it developmentBottleneck: some great user demand market, a good technical support, but difficult to turn it into cash flow into revenue problem where exactly? experts believe that also need to make three efforts. First, you need to change our understanding of the convection media, streaming media from the technical level has been promoted to management level, only so that we can open our imaginary space, the streaming media technology to truly reflect the value of it. From HBO and other pay television business strategy, we can feel based on streaming media technology video market and, most importantly, business model, not the technology. For utility market, the technology is finally just played a security role, streaming media technology in the broadband market in this area. Secondly, the streaming media technology developers to emphasize the product product value. This will enable operators to quickly accept the product, the product can more closely to market requirements. Backtracking communication and IT industry, every successful products have such a trajectory to follow: first by the technological revolution found a potential market of breakthrough, then quickly lower product cost, make technology do for end users of maximum transparency, so that the integration of new technologies, products and applications quickly open and hold terminal market, to obtain maximum benefits.　　So for developers, and does not require the advancement of the blind pursuit of technology, but rather should fully exploit the technology itself, highlighting market value is the value used to complete the technical products convert between value and earnings. For example, now on the market, many based on broadband streaming platform products, at the present stage of China's broadband network bandwidth (512kbps cent) applicability, on Terminal (PC, TV, handheld Terminal, etc.) support, on a variety of business strategy (PPV, advertising strategy, vendor strategy), the flexibility of user behavior, the embodiment of what is fully taken into account, is unknown. Once again, in operation, to focus on broadband industry value chain of integrity and perfection. Traditional Internet development, let the world see clearly that any value chain incomplete industry will be a Flash in the Pan, in the historical record is only a small pulse. To address this reality, help us to clearly see the running track of modern business. In the broadband industry, from content manufacturers, content service providers, network operators have to users, to build a broadband applications services product lines. Under the management level, is a large number of application software developers, terminal equipment manufacturers, system integrators, platform providers of technical support, and related banking, sales, marketing, consulting and services is to build a broad industry environment, numerous roles can be dispensed with, only stick together to a total of prosperity. Streaming media is a bit just wearing red shoes actor, if the industry value chain of manufacturers able to support each other, and if the community can give some cheer, believe that wonderful moment will come. This new product markets, in fact, there is already a pioneer in the market gaps opened. For market development forecasts and multi-directional, multiple roles, some shrewd manufacturers have shenshe. Currently, Microsoft, Shanghai fullhan microelectronics technology has and Hangzhou Netcom, Mi crosoft, Intel, via, TCL, Shida, Skyworth, and other leading manufacturers jointly launched the suitable for China's current broadband network IP set-top box solutions for traditional telecom operators to launch on an existing network for television terminal market programme and set up a broadband streaming media laboratory for broadband streaming media application market offers good technical support. We look forward to more participants can pass viable technical solution for operators to provide diverse broadband streaming media business, ultimately enabling broadband streaming media application service truly integrated into the end-user's life.

College】【weak microphone recording on the computer to use.

present, many users and handset users to chat to the purchase of winning victory after the capacitor or dynamic microphones to go home in the use of a variety of issues. .Here I will be victorious, I will introduce in detail the specific use of the microphone and hardware requirements and teach you in computer chat rooms for video recording and singing victory microphone connection and set specific installation methods. . First we have to understand common sense is that winning is not the production of specialized computer dedicated computer microphone microphone, so there are many users to buy the home directly connected to a "TRS turn a small three-core" (also called .Big turn small) plug to plug in the computer sound card to use the approach is very wrong, and will also appear the situation too silent or sound. .Because our ordinary civilian board sound card is not possible to push dynamic professional microphones. .Ordinary sound card can only push a class of micro-computer sound wheat head. .So if you still worry about spending hundreds of pieces to buy a professional microphone why not take a computer, then you do not fee God. . Professional microphones use the computer if required to do the first level of an amplified microphone signal, so as to allow the microphone audio signals collected enough to recognize and play back a good sound effect. .Such as performance, when entering the amplifier to the audio signal amplification done deal, so we can hear the sound from the speakers. .Using the same computer, we want professional quality microphone through the sound card and issued, we also need to do it between the microphone to the sound card a signal amplification (sound amplification system although there are, but only drive the computer wheat). .Amplified microphone signals have enough POWER to capture your wonderful voice and guarantee results. .The first stage amplifier, we generally use the "microphone amplifier" or put function with the words "console", it is best used in conjunction with the two. . Brands in the market put a lot of words, such as ICON, SAMSON, BEHRINGER and so on. .Mixer brand is also very much in the choice to choose their own brands and models used. . If you are buying a dynamic microphone, usually on the phone and then put into the sound card or mixer can be used, but is the condenser microphone, then if that still need power supply for the microphone. .So after winning the microphone users to understand their purchase to buy a moving coil type microphone or a capacitor-type microphone. .Very sensitive condenser microphone for recording studio which was used, it is very accurate record of your audio signal every minute, so condenser microphone requires 48V phantom power supply to work. .Victory condenser microphone in the medium and large packages are equipped with phantom power in the power supply. .If not, still need to purchase, then up, and some mixers have phantom power supply functions, there is not such a mixer to the addition of power supply. . Also explained that the users to buy the microphone moving-coil or capacitor in the choice of when to buy according to their own needs, moving coil type microphone is mainly used in live performances and other places, because it can be to some extent .beautify the sound and hide flaws. .The studio recording microphone is mainly used in the recording area, which because it is very sensitive and will definitely not let your voice on every detail. .Do not think it looks nice condenser microphone is also more professional than the moving coil of the good, but they perform their duties in Oh. . Then give us a presentation computer for recording and singing in the video chat room equipment specific connection method. . General, computer recording and singing in the video room, the microphone device is basically the same. . We first take a look when using dynamic microphones and computer connection method. .If we follow the general put the microphone ----" --- -----" sound card or microphone, "then put -----" mixer -----" order to connect the sound card. .(Figure) simple dynamic microphone and computer connection method: again mixer is added after the connection method, in a chat room, then use the mixer to sing not only the volume of real-time control of your microphone is also .can mixer EQ, GAIN and effects feature allows you to achieve the performance level of the sound effects. .After using the mixer and can not use the word free. .(Figure) If you want to get top results chat room singing the words that you need to put words together and mixer configuration, the connection is as follows: (Figure) condenser microphones to talk about again .connection method, the same basic method and moving coil, but more of a condenser microphone power supply 48V phantom power, (or if there is, then put the table with phantom power do not need to) basic connection method as shown in Figure: condenser microphones and mixers used in connection method. .Note: The condenser microphone and the mixing console must be inserted when the 48V power supply on the table the black microphone jack, you can not use insert TRS moving coil input: (Figure) finally .excellent condenser microphones configured to connect: (Figure) victory over the microphone and the computer is connected to a variety of ways, and I hope useful. .Also to be noted that our computer sound card is also very important. .Ordinary board sound card can not be used recordings, innovative sound card can only meet the needs of singing voice chat. .To want to do music, then you must use professional sound card. .Condenser microphone with phantom power or a mixing console cable must use a special audio cable, audio cable ordinary internal welding method and not the same as a dedicated condenser microphone, you can also buy a special victory condenser microphone cable. .Well, stop here. .I hope everyone can play out their most personal music. . .

College】【weak Chinese translation of common import audio --- Power By 【China】 weak home network.

Caton bang; Adcom Aegean; Cary-Ghali; Alchemist Europe and the United States; Energy energy; < .BR> ConardJohn  son poems drunk; AUDIOAERO harmony; Accuphase golden voice; B & W BAUER Credo Cointreau; Atoll reef Bryston worship things through (million Fujitsu); Creek Long Quan (laser card); Audiolab Audi Rimbaud; . Bonston Boston; Celestion Variety Long; AUDIONOTE sound noble; Bow Bow of God, Denmark; Classeaudio drive potential; AudioAnalogue Gagaku; Blueroom Baolong; Copland Copland (valley blue); AvalonAcoustics chief; Bona Bao Yun .; Canaryaudio canary; Avance crown; Burmester of Berlin Voices; Cambridge Cambridge; Amphion Ophelia .Del; Bose, Dr.; Cardas Car'das (Qatar, the Jada sound); Audiotechnica triangle; cello cello; . AE love arts; Densen Prince of Denmark; chario Zhuo Li; Arcam Masatoshi; Dali Daniel; < .BR> CHORD chord; ACROTES Ya do; Denon Denon; Castle Castle; Audioquest line St.; < .BR> (AQ) Dynaudio Tanner; ex  posure Lippo sound..

【 Weak current College 】 mixer control panel on the role of the various interfaces

When the initial contact with a mixer, can easily be it panel presenters, a large number of knob and push rod swindle. First of all let's take a look at the left panel. In fact, left on a per the significance of the push rod and knob. So you only need to focus on understanding a channel operation method can overall control. Fewer branches of mixer with 4-channel and 8-channel input control, the way most 96 road even more. This mixer has a 8-channel input control, we only take one to explain the role of each section.
1.MIC: microphone input interface
Microphone input via XLR female seat, acceptable equilibrium or non-balanced low level signal, using a professional moving coil, capacitive or Ribbon-low impedance microphone, if you are using a non-balanced microphone needs to make use of the shorter the better microphone cable to avoid radio interference noise.
2.LINE: high level input interface
High level input is typically through TRS1/4 stereo PhoneJack or TRS1/4 "into the microphone audio sources MonoPhoneJack outside signal can be transmitted through high level input to the mixing machine, stereo input is balanced PhoneJack, identical to the XLR, but if you must use the non-equilibrium equipment, wiring available MonoPhoneJack cannot be too long (4.5m within).
3.LINE-20DB: attenuation 20 DB keys
Press this key to input level attenuator 20 DB. General environmental noise is large, device-level relatively noisy or level too high when using the key. Use it on all of the audio input signal frequency attenuation, in order to achieve the volume smaller noise or electrical noise filter out. Sometimes appear excessive input level signal, such as no attenuation, the attenuator control range is significantly reduced, only a very small area within gliding, causing the volume output control very difficult operation. You should press the key to increasing the attenuator range of effective control.
4.PEAK: peak LEDs
Peak lights, warning users input channel of the signal is too strong. Find Peak lights, and let this situation continue, the mixer starts self-protection, cut off the audio source output. Therefore, you should adjust the input volume size, otherwise, the sound mixer audio output will be automatically cut off. You can use control including: Line-20DB, decrease the Gain, low attenuator, generally to reduce the Gain.
5.GAIN: gain knob
It is used to adjust the size of the input signal level. Input signals to the output level to the knobs and faders of the input cells together. Obviously, the knob clockwise angle increases, the higher the faders, input signal output level, the greater the upgrade, or the input audio signal at the output of loudness. Gain range is 20 DB to 60 DB.
It is worth noting that gain too high will make the channel load overload, resulting in the sound is distorted; too low then the background noise significantly, may not be sufficient to provide mix output signal levels. Use high level input to gain go small. Gain knob is as sound input mixer, adjusting the fit, to guarantee the sound mixer next level of processing circuit can receive a full and "clean" signal.
6.HIGH, MIDDLE, LOW: three Equalizer knobs
High, Middle, Low-frequency, respectively on the low-frequency, enhance or attenuation, control the range of plus or minus 15 DB. If control is especially useful when your voice, you can very accurately decorated performers of sound.
Bass: 20Hz ~ 500Hz appropriate, bass, voice full relaxation. Insufficient sound thin, excessive lifting the sound made when dull, luminance drops, nasal sound enhancement.
Baritone: 500Hz ~ 2KHz appropriate sound thorough bright. Insufficient sound obscure, excessive lifting will produce similar phone voice.
Treble: 2KHz ~ 8KHz is the frequency of the sound level. Insufficient sound penetrating power drops, too strong when the masking language syllable recognition so that teeth tone aggravation, nervous tone.
Director sounds7.MONITOR: volume knob
Adjust the path in the listen on line volume size. If you do not use additional access to listen to the Director of a mixer device, this knob can be placed in 0.
8.EFFECT: output to effects knobs
Adjust the knob determines the output to effects level size. If you do not use external effects, then this knob can be placed in 0.
9.PANPOT: sound like a knob
It is used to adjust the channel signal on the left and right channels of a stereo position. Adjustment range left channel 5-right channel 5, if you do not need to create special effects, usually at 0.
10.PFL: attenuator before listening key
When attenuator before listening key is pressed, the monitor output sent out only the road signals, use this key to effectively identify sources of noise. When there are multiple input of PFL is pressed, the listening distance
Out will be sent out the pathway of the mix.
11.FADER: Attenuator (volume faders)
Determines the channel signal is sent to the bus output volume size. Volume faders is actually a attenuator for on the channel output signal attenuation. When the bottom-most faders (or volume knob located on the left-most), signal attenuation is infinite. At this point, the channel does not have signal output. Adjustment range-∞ ~ + 6 DB, generally suitable to 0, more than 0 will cause the sound to produce a certain degree of distortion. If you must raise the level of the signal, the general use of the appropriate increased Gain, without the attenuator lifting more than 0.
Because music input for continuous, and voice input into breaks and therefore have the operation. In the musical input rail operations, general use"Fade in" and "fade out" effect. The operation is to slowly sliding attenuator, then gradually speed up operations, avoid uniform sliding or instant large operations, which will make the audience feel uncomfortable. In the voice input channels, generally use "one step". That is, when the human voice in needwill probably look to the faders suitable location, then listen and level meter displays a little adjustment. Without the need for the human voice, to get to the bottom-most faders to avoid unnecessary sound is input into it.
Next, we look at mixer right side of the control panel. Before the left side of the Panel is used to adjust the input signal, and the right side of the main responsible for the regulation of the output signal.
1.MONITOR: monitor output interface
Provide external listening device interfaces, used to connect external listening device.
2.EFFECTSEND: sound mixer output to effects interface
The input signal is sent to an external amplifier.
3.AUXINSTEREO: auxiliary stereo input interface
Connect an additional stereo input device.
4.EFFECTRETURN: effects return mixer interface
Will go through an external effect device handling return signal access.
5.7.MASTEROUTPUTRIGHT: total output right channel
6.8.MASTEROUTPUTLEFT: output the left channel
Provides two interfaces for left and right channels total output. Output signal to go through the various adjustment after the final signal.
9.POWERON: mixing console switch
When ON one side is pressed, the mixer will power on, POWER side is power off.
10.HEADPHONE: monitoring headphones output interface
Connection monitor headphones. When any one channel PFL is pressed, the headphones signal and output signal. When a channel PFL key is pressed, the output is for all
PFL key channel signal mixer (including through the effects of sound)
11.AUXIN: auxiliary stereo input knob
Adjustable auxiliary stereo input level.
12.PFLON: PFL led
When a channel PFL keys are pressed, this light is lit.
13.EFF.SEND: output to effects knobs
Adjust output to the external effects of signal's level.
14.HPLEVEL: headphones volume knob
Adjust the output volume of the headphones to listen.
15.DELAY: delay effect knob
Adjust the input signal to the intensityof the delay effect processing.
16.18.HIGH, LOW: second paragraph Equalizer knobs
Balanced output for listening.
17.LEVELMETER: level meter
Three color level meter to monitor all input, group and mix signal meter to peak type display. Displays the range of-20 DB to + 6 DB. There are two LED light show, the individually with R-CH L-CH
Represents a mix of left and right channel output level size, if you press the PFL key appears as is pressed the output level of the channel. General should peak at 0, unsustainable appear red.
When the mixer power is connected, the red light ON Office will be lit.
19.REPEAT: echo effect knob
Adjust the input signal to the intensity of the reverb effect processing.
20.EFF.MON: effects to listen knob
Adjust the audio source through effects processing, output to the monitor size.
21.PANPOT: sound like a knob
22.23.PFL: attenuator before listening key
24.MONITOR: sniffing out attenuator
25.EFF.RET: effects return attenuator
26.GRAPHICEQUALIZER: graphic equalizer
On total output audio source signal is compared to the delicate balance adjustment. Frequency is divided into 6325

College】【weak right amplifier output terminal connection method --- Power By 【China】 weak home network.

present, the power amplifier for the public address system there are two: one is scheduled to stop outputs, such as the output resistance is 250Ω, the load required to connect multiple speakers to be calculated through the impedance converter, .with, to ensure that multiple speakers in parallel after the load impedance is equal or close to 250Ω, to achieve the best match. . The other is the constant pressure-type output, the international standard for the output of 100V or 70V, the output of certain products of domestic 120V. .Because each radio is equipped with loudspeakers have been determined based on the size of their power transformers, the use of constant voltage-output amplifier connected to multiple load speakers, just like the installation of lighting the lamp, as one by one in parallel, connect easily, so it .a public address system equipment configuration of the established formula. . Using constant pressure-type power amplifier output, usually in the back panel has a 100V, 70V, 0V terminals for use with different power output. .So, how should we in the project is properly connected it? .Let us illustrate: engineering application one: use a fixed office address system amplifier output compression, back panel of the 100V, 70V, 0V terminals, with the AMAPC-865B Ceiling Speaker .5W output power, with 100V transformer. .The correct connection method is: to ensure that all ceiling speakers and non-load power of the power amplifier output power of greater than 80% of the premise, all the ceiling speakers of the positive and negative terminal, respectively, and then up, then connected to the amplifier .0-100V terminal, then power output ceiling speakers 5W; ceiling speakers if all the positive and negative terminal, respectively, and connected up, connected to the amplifier 0-70V terminal block, then the power output ceiling speaker .reduced to 2.5W. . Engineering application two: a residential area broadcast system used constant pressure-type power amplifier output, the back panel of the 100V, 70V, 0V terminals, equipped with lawn mushrooms speaker output power of 15W, 70V available .transformer. .The correct connection method is: to ensure that all lawn mushrooms in the load power of the speaker and not more than 80% of the power amplifier output power under the premise of lawn mushrooms all the speakers are, respectively, and pick up the negative side, and then connected to the amplifier .0-70V terminal block, then the lawn mushrooms speaker output power of 15W; lawn mushrooms speakers if all the positive and negative terminal, respectively, and connected up, connected to the amplifier 0-100V terminal, then the speaker output power lawn mushrooms .into 30W. .At this time, turn up the volume, most likely burned speakers. . Engineering application three: a school broadcasting system made use of early-type output of the power amplifier constant pressure, the back panel of the 120V, 0V terminals are equipped with wall-mounted frets 30W output power, with .100V transformer. .In such situation does not match the output voltage, directly to the wall if access to 0-120V Yinzhu terminals, since the input power is beyond the frets 20% of rated power, open the volume, is likely to burn frets. . Order to avoid damage to equipment, should be taken to change the output power of the flexible approach frets. .Yinzhu generally have two wall-mounted, three-tap to choose different output power, such as: AMAWS-83030W Yinzhu wall power output with 30W, 20W, 10W, 0 three-tap. . The correct connection method is: to ensure that all wall-mounted in the load power of the frets and not more than 80% of the power amplifier output power, under the premise that all wall-mounted Yinzhu of 20W, 0, respectively, and then end up .then connected to the amplifier terminal 0-120V, then the output power of wall-mounted frets as 26W, and can basically meet the demand..

【 Weak current College 】 projector installation and adjustment of small details

Projector as the most capable today of office equipment has been more and more companies are concerned about, and have more and more organizations are looking to purchase projectors to help Office helping hand. So since the projector will certainly relate to the latter part of the installation and adjustment, mainly due to the installation and adjustment of the process, there are some small details often are consumers to ignore, so want to give the consumer make a wake, but today we focus on is the installation process in some detail.
1, cradles of installation
Hanger for a square frame in the upper part, there are 8 diameter of 6 mm hole, this eight-hole is the hanger and the upper ceiling fixtures that are connected to the mounting holes. Fittings installed base surface and ceiling surface distance, depending on whether the projector is hidden to the ceiling. If you hide the top internal, this distance should be greater than the height of the shrinkage after the hanger and the height of the projector itself.
2. install the projector
The bottom of the projector hanger fixed universal hanger, depending on the size of the projector, the adjustment lever fixed universal hanger, connected to the projector.
3. electrical connections
As shown in wiring diagram correctly connect the power cables, control cables. The projector itself various wires install in the following manner: two separate sets of rope on a number of small round ring, hanger reaches maximum stroke, the first projector conductors plastic strap and a small round collar connections, and then from the bottom up, "Z" word forms are connected to two with the rope. When hanger movement up and down, the projector's various conductors will be between two rope.
4. adjust the height of the hanger
Hanger upper limit switch with two, upper and lower control hanger, respectively. Loosen the bolts by tags and move around to adjust the limit switch hanger location, and then fasten small bolts.
Note that the installation here does not mean that you can immediately use the projector to appreciate the projection image, in order to be able to get better results, we also must be made to adjust the settings. Because just bought back the projector settings are the standard values, the cast out of the effect is not necessarily the best, so convenient for future use, be sure to make some adjustments to many parameters.
First is the resolution of current computer the most common resolution is 1024 × 768, if you select the projector supports 1024 × 768 resolution, Basic does not need adjustment, but if you use the projector supports a maximum resolution of 800 × 600, but the computer settings of 1024 × 768 or more, in this case, the projector will automatically display images with compression, although we do not normally see the image, but the screen display quality has greatly diminished. Therefore, according to the projector supports resolution to set the resolution of the video source, so as to achieve mutual match to get the best results. [fenye]

Projector usage tips

Finished installation and adjustment last longer as you send some projectors use of some small tips. Because the projector is different from ordinary display products, it is more necessary caution, finally we'll provide some tips on using them to better use and protection of the projector.

1. open the projector power supply before connecting the projector cable properly acknowledged, at the same time to ensure that the video source has been normal output. Complete projection connection and turn on the projector, you also need to switch good output. Because the projector output there are three ways that you can hold down Win logo key and F5 (connected with a laptop, you can press the Fn key and F8), to choose the appropriate screen output.
2. familiar with projector user's eyes, the projector is just like a regular TV, open will open; when you want to close, most of them are directly cut off the power. As everyone knows, this operation is using the projector's "taboo", because the projector in the prolonged use of direct shutdown will seriously affect the projector bulb life.　The correct boot sequence: first projector power button, and then pressing the projector Lamp on the operator panel button, wait for the blinking green light stops flashing, the power-on. Correct shutdown sequence: first press the Lamp button, when the screen is really want to shut down when you are prompted, and then press the Lamp button on the projector Control Panel then the green signal lamp starts blinking, wait until the projector internal cooling fans full stop, green light stops flashing, then turn off the projector, disconnect the power supply. In addition, each time you open, shut down, the best guarantee for a 3 minute intervals, in order to allow sufficient heat dissipation of the projector. Open, shut down too frequently easily lead to the projector bulb exploding or projector internal electrical components were damaged.
3. the projector lens is clean or not, will have a direct impact on the content of the projection screen clarity, experiencing all kinds of circles on the screen or spots, most of the projection lens dust "provoked". At the same time, the projector lens is very delicate, not sometimes need to cover the lens cap to avoid sticky dirt, cleaning professional lens should be used when paper or other specialty cleaners to clean the dust on the lens of the projector.

Weak current College】【KTV mixer control Essentials --- Power By】【China power house network.

Master the correct switch order
Mixer power on the attenuation of faders before should be placed in a minimum location to prevent the surge voltage impulse sound source processing equipment and power equipment.
Open the mixer power, in accordance with the first small signal, after large-signal ", open source and peripheral device power, then open the amplifier's power. Shutdown before the attenuation faders to La, at the same time power discharge flat tuning knob to a minimum, in accordance with "first closed after large signal, turn signal, turn off power amplifier power, sound mixer power and other device power.

Selecting the right input level
Fixed value decay key PAD and GAIN-gain control knob with use, adjust the input level. Signal level is too large, such as CD,
ID, VCD, DVD player, double deck, high level audio sources are to PAD keys pressed in order to ensure that the signal level does not exceed the input level of dynamic range, so that it is in good working condition. When the input level in-between-the-60dB, the GAIN knob to adjust the fit of gain. For example, audio source is low sensitivity dynamic microphone (sensitivity is-55dB), you do not need to PAD the key pressed, you can GAIN knob placed-55dB corresponding location. If this is the high sensitivity of the microphone (sensitivity is-35--45dB) will be able to GAIN knob placed-35--45dB corresponding location, so that the input level is appropriate, at this time of distortion and noise are low. In General, in the fixed occasions where fine GAIN should not go after moving it. Never adjust the GAIN to change the volume.

Correctly adjust the input level and the input gain
Min level faders and input gain control to match the appropriate, such as min faders is too low, and the gain is too large, when the signal input, min faders has not reduced margin, so it is easy to cause overload; if someone accidentally pushed the faders, produces the damage after the class amplifier and speaker of the serious consequences. Correct adjustment method is:
(A) initially, faders and the gain knob will be transferred to a minimum.
(B) of the faders to 70% (no more than the master faders).
(C) slowly rotate the gain knob to CLIP light is not flashing the position before. If the input channel receives a microphone signal, rotate the gain knob, when the receiver is then generated screech to a level of direction cycles is a suitable location. Never adjust the input gain to alter the volume size, so that the cause of the overload distortion or a lower signal to noise ratio, after the class irreparable, to change the channel signal strength, volume size, adjust the channel faders should be.

【 Weak current College 】 large screen projection is it sew concatenation technology---Power By 【 China power house network 】

Large screen projection is it sew concatenation technology already from the initial virtual simulation and virtual reality applications has been extended widely to command and control, virtual simulation and training, industrial manufacturing and design as well as scientific research and complex decision-making process, and in the exhibition, advertising, entertainment and more prevalent in the field of application. After the industry manufacturers for many years technology development and efforts to present a seamless splicing technology has been developed to a very mature stage. Due to the large screen is it sew concatenation performance requirements are applied in very high places of special application, for the equipment of high reliability requirements are high, so high for large screen not sewing the concatenation projector procurement in will not be able to mix business with pleasure to the other for education, entertainment and other aspects of commercial projector, its specification have more stringent requirements

Big screen seamless splicing technology is a special, requires relatively high projection display application, you can implement a multi-screen image fusion, and set the concatenation of gap reduced to a minimum so that the complete heavy match of multi-screen technology. Big screen seamless splicing technology not only need to complete hefty screen, Super projections that the super-size screen projection also have special requirements. At present, through the built-in seamless splicing technology, high-end projectors or through external to sew the concatenation processor may implement super sharp pictures of seamless integration. Built-in seamless splicing technology, high-end projector main branch as ChristieMatrixS + 2K, Christie highlighted projector DS + 60, BARCORLMG5 "performer" projector, 3Dperception Visual SX25 + projector, Panasonic PT-DW7000E, etc. (details refer to: applied to big-screen mosaic of high-end professional projector recommended); external to sew the concatenation processor mainly Norway 3Dperception integration build controller, depending on the (Christie) edge fusion processor Imager.

3Dperception Visual SX25 + projector 3Dperception fusion generate controller
Big screen seamless splicing technology development has experienced a pure hardware integration technology, pure software and hardware integration technology and Synergistics three phases.
Pure hardware integration technology through optical shading to fusion image, pure software Fusion is handled via electronic lines to complete the image fusion, hardware integration technology mean both optics fusion processing and electronic fusion.
Because hardware integration can better handle the fusion image of black balance software fusion can better deal with the white balance of the image, the combination of both hardware and software integration technology will be able to compare the perfect realization of partial color image fusion of emergence.
From large-splicing effect, seamless splicing technology has undergone three phases: hard-edged splicing, overlaps splicing and soft edge Fusion splicing.
Hard-edged splicing is clearly split lines (i.e. physical slot), a panoramic view of integration cannot be achieved; overlap concatenation displayed refers to two projectors cast out of the Office of the flattener to image superimposed overlap, but this kind of concatenation obvious flatten Office as brightness overlay, there were light areas of the ills that affect implementation of seamless effect.
Soft edge Fusion splicing through edge integration technology of processing, which implements the full integration of both sides, and eliminate overlaps splicing caused too light areas and soft edge Fusion splicing can adapt to the plane, cylinder, sphere, etc. all kinds of surfaces in the shape of the mosaic, have broader applicability. Soft edge Fusion splicing technology is now mainstream technology, it is the future direction of development.

Weak current College】【KTV microphone use eight cream --- Power By】【China power house network.

Now people use microphone is very frequent, but really good microphone not many people. The so-called "good" is nothing more than a good pickup efficiency, long service life and health. The following talk often seen in several major error, we use the taboo.

1. try to sound when you tap the microphone and cream to the microphone inflatable
Because the microphone pickup parts more precision, and part is a delicate, tap the microphone or blow to the first-class easily damaged or part shift that ultimately affect sound quality.

2, leave the cream microphone sources too close too far
Microphone pickup is the best distance to 10 centimeters. Some of the "leadership" speech is far away from the microphone, a singer with a microphone, too much cause pickup sounds too small, then the volume faders to push the extremely easy to cause Whistler; too close to the air when the speech is also collecting into the sound, putt-putt "interference".

3. leader bogey la microphone
When submitting the handset microphone bogey pull. Because the microphone has a certain weight, often pull the leader, it is easy to result leads broken and plug contacts is not good, cause pickup.

4. After using the cream does not turn off microphone sound power
In a meeting when speaking or singing, switch off the microphone switch in time, this time as tone control Division nor timely close Mixer volume faders: on the one hand, the other noise or pick up in one hand, and put your unnecessary speech sound playback.

5, JI Zui cleaved microphone use
Some people use without notice or pursue a nearly stresses effect. Often a mouth stick live microphone, but this will not only destroyed the microphone of the normal frequency response, on health also caused great hidden microphone NET cover many of the bacteria is on.

6. JI long no microphone, do not exit the battery
Now General wireless microphone or meeting microphone are need battery-powered. If a long period without a microphone, you should exit the battery to prevent battery leakage, corrosion of the receiver.

7, place a bogey microphone free
The receiver is a precision device should be placed in a clean, dry, non-corrosive gases or dust, also should handle with care, we must avoid falling to the ground, or else in all likelihood be damaged.

8. cream for capacitive microphone, with phantom voltage blindly
Because of the capacitor capacitance microphone required polarization to work properly, so when using capacitor microphone, with phantom voltage. We must open the phantom power switch sound mixer, bearing in mind the voltage and polarity, otherwise, instead of normal use, may cause damage.

Weak current College】【Equalizer parameters and debug in Visual FoxPro.

1, equalizer to adjust the method:
Subwoofer: 20Hz-40Hz, appropriate sound strong. Control of Thunder, bass drum, organ and bass sound. Excessive lifting will make music become cloudy.

Bass: 40Hz-150Hz, is part of the basis of sound, its energy accounted for the entire audio energy of 70%, is the performance of the musical style of important ingredients.
Where appropriate, the bass sound relaxation properly, when you full soft enough, sound thin, excessive lifting 150Hz will make the sound from a dull, luminance drops, nasal sound enhancement.

Bass: 150Hz-500Hz, is part of the structure of the voice, the voice at this location, is low, the sound of singing will be inundated with music, sound, soft but unable to find the right upgrade is thick and strong, increasing the intensity and loudness of the sound. When upgrading over the bass becomes stiff, excessive lifting 300Hz Department 3-6dB, if coupled with reverb, it will seriously affect the clarity of the sound.

Baritone: 500Hz-2KHz, contains most of the musical instruments of low harmonic and overtone, Xiaojun drum and percussion instruments is the feature code. Appropriate sound thorough bright, insufficient sound obscure. Excessive lifting will produce similar phone voice.

Treble: 2KHz-5KHz is string feature codes (La musical bow and string of friction and noise, plucking the strings of your fingers touch the music sounds a). Insufficient sound penetrating power drops, too strong when the masking language syllable recognition.

Treble: 7KHz-8KHz is the frequency of the sound level. Excessive increase makes the Piccolo, flute sound, language pronunciation of teeth and timbre nervous aggravation.

Extreme treble: 8KHz-10KHz

Appropriate, the recorder triangle and a sense of three-dimensional metal penetration rate is high, the rhythm of the sand clock. Excessive lifting will make the sound is natural and easy to burn high frequency units.

2, balance, pleasant voice should be:
150Hz following (bass) should be plump, softness and elasticity;
150Hz-500Hz (bass) should be thick and strong 100 not cloudy;
500Hz-5KHz (treble) should be thorough but not stiff bright;
5KHz above (treble) should be fine, smooth and not shrill.
The frequency response is flat: sound natural fullness and flexible, clear and pleasant garden level. Frequency response more peak and Valley: voice rough harsh cloudy, treble, no nervous sense of depth-prone feedback whistling sound reinforcement.

3. frequency of experiments features:
30 ~ 60Hz boring if there is no considerable loudness, the human ear is very difficult to feel.
60 ~ 100Hz heavy 80Hz nearby can produce a very strong sense of "heavy" effect, loudness is high also does not give the comfortable feeling, can give a strong boost.
100 ~ 200Hz plump
200 ~ 500Hz efforts easily cause mental buzzing off.
500 ~ 1KHz clear near as upgrade 800Hz 10dB, will obviously have a noisy, narrow sense.
1K ~ 2KHz translucent 2800Kz near bright sense of relationship with Max.
2K ~ din't 4Kz sharp, sharp 6800Hz formation.
4K ~ 8Kz crisp 3400Hz auditory fatigue caused by susceptible.
8K ~ 16Kz slender slim clear 7.5KHz pitch ".

P.S.
1.20 ~ 40 the band sound of the majority feeling is soft bass instead of powerful, can see through the test. Look for the band to drum lifting will have any effect.
2, 40-150 is a sound basis for sure, but never less than 70 per cent, and the voice of the nasal nor in this band, probably in the 250 or so.
3, 150 to 500 this frequency band, was a time when you want to handle very carefully by the band, must not rely on the lifting of this band for the human voice. A little carelessness will have a mission.
4. promotion of the "excessive 300Hz Department 3-6dB, if coupled with reverb, it will seriously affect the clarity of the sound. "It should be said that as long as the low frequency part with reverb, affects the clarity of sound. Of course, now the mix skills, this rule is not very important. Because we often in Europe, and RTHK Studios saw them to drum and bass plus ultra short reverb.

None of the above is a reference value, in fact or in accordance with the production of the actual circumstances! hope to provide for everyone to refer to the help!

Monday, February 14, 2011

Weak current College】【acoustic concepts --- Power By】【China power house network.

People were able to hear the sound, is due to the Sonic vibration caused by transmission medium (eg air, water, concrete and elastic substance) propagates into the ear. From the sound source or vibration source directly into the ear is called ."direct sound, sound through objects reflection of incoming ear is called" reflection ". Human ears distance approximately 15 ~ 17 cm, this distance makes the ear with a very accurate to determine the characteristics of the sound source position. For example: sounds from .the left to begin entering the left ear, right ear sound than the left ear late its time difference = ears distance / speed of sound, 0.44 ~ 0.5mS. This time difference to listen and feel the sound comes from the left. So direct sound .to distinguish the sound source position plays a decisive role. So when people listen to music with three-dimensional sense and sense of space. In reflections arrive earlier in the ear of Sonic strong, this strong reflection called early reflections, after which the sum of .the reflections are called mixed sound. Ear listening range 20Hz ~ 20KHz. Below the 20Hz called infrasound, higher than the called ultrasonic 20KHz. Sonic vibrations transmitted by the week, the distance is called "wavelength" λ represents the transmission of the acoustic one second .is called the "distance" with a wave speed c represents the Sonic vibration frequency of one second is called "frequency" f represents the relationship between them: λ = c / f sound waves during the transfer process has the role of mutual interference. Two .frequency in the same direction as the same, vibration and coherent sound source produces a sound wave overlapping when there is interference. If they are the same phase, after two waves superposition increases sound pressure strengthened; on the contrary, their phase contrast, after two .waves superposition pressure amplitude decrease, if two wave amplitude, will be fully offset. Because of the interference effects, sound waves often makes space of sound field appears fixed distribution, forming the crest and the trough (from the frequency response curve looks like a comb .filter effect), namely: audio terminology often say - standing wave phenomena. In the Auditorium when due to wall of sound reinforcement of reflection will also appear in Sonic interference phenomenon. If it is a pure tone audiometry (sine wave) signal, such .interference would necessarily be caused spatial sound field of the great differences that have local Sonic will strengthen, some parts of the sound wave will diminish or even completely offset, as the "dead point" (no sound). Fortunately, language and music is not .a sine-wave but complex waveform, this complex waveform using Fourier series expansion is more of a different frequency, different amplitude sine wave. So there is "the" "makeup" effect, so that interference effects are less obvious. But! because different .frequency signal generated by the interference effect, certain frequency signal enhancement, other frequency signal attenuation, often resulting in room transmission characteristics of non-uniform, that is why you want to use the room equalization ". Described by the sounds on the strings of sparse .and dense alternately changing wave, and sparse and dense is air pressure changes, and then through human eardrum to reflect incoming air pressure, thus hear the voice of the brain. Sonic is to describe the sound of physical phenomenon, common waveform representation. All acoustic .have attention! "wave" in nature. The resulting sound conditions for two: 1, must have vibration or oscillation source. 2, Sonic's delivery must rely on the media..

College】【weak sound system debugging method resolution --- Power By 【China】 weak home network..

debugging is generally divided into sound engineering and sound system debugging debugging debugging here to tell us about the steps the system, the following system debugging steps that I generally use, and introduced to share. . 1, line check: according to the design, carefully check the connections, make sure there is no problem. . 2, set the initial state device, the amplifier input set to a minimum, all the input and output peripherals knob is set to 0 dB position or middle position. .In accordance with the previous level after level in order to power (first not the amplifier), check all equipment power is normal, to the amplifier power. . 3, the initial check system status: appropriate to open a large amplifier gain control, CD music in a familiar place, adjust the mixer input level to the basic normal position. .Slowly push the fader from the console a bit and listen to the voice of speaker is normally given to whether the distortion, if not properly checked off immediately. . 4, speaker and polarity detection system: the system is normal, turn on all equipment and power amplifier set at maximum level, pull down the output faders mixer, phase analyzer generator access to the mixer input .channel, turn the power to adjust the output gain phase analyzer and mixer input gain to the mixer instruction sheet is 0 dB. .Slowly push the fader from the console output, etc. issued by the speaker in the "pop" sound to achieve sufficient loudness (if the loudness is not enough, the test results are sometimes inaccurate), detected by the phase of each speaker to check whether the phase or .speaker described the same specification. .Detection best to turn off the other speakers, to prevent interference, one by one test is more accurate. .If there is not normal, check the speaker cable is reversed or whether the system cable inverted. .Turned or replaced after the test. . 5, phase adjustment: If you use ultra-low-and full-frequency combination, due to the presence of sub-frequency system and the installation position of the reasons, there may be cross-frequency interference or delay the phase caused by different problems, .So the need for phase adjustment. .Pink Noise (PINKNOISE) generator receiving input channel mixer, adjust the levels to the normal position, phase meter test on the pitch, microphone, and speakers into the triangle position. .Raise the mixer output fader, check the entire frequency spectrum analyzer screen with the subwoofer crossover frequency band near the valley point there does not appear. .If so, the corresponding band equalizer to enhance, if not up to enhance is the presence of phase problems. .Will directly affect the phase problem appears sound, but nothing resolved with the equalizer. .To solve the problem need to adjust the crossover phase of the phase angle or time delay between speakers. .Adjustment, note the spectrum analyzer display, the first frequency divider of the phase angle adjustment to see if there is no improvement, if there is improvement, determine the best value and then adjust the delay time, delay time adjustment depends on site conditions .If the subwoofer from the seats near to delay the need for regulation to do the bass, is also watching the spectrum analyzer screen, adjust the delay time for the curve as flat point. .Phase to minimize the interference. . 6, frequency equalization: After doing the above regulation, you need to adjust the system frequency response curve. .Spectrum analyzer to test the microphone on the seat to a location within the region, play pink noise source, watch the spectrum analyzer display, on the defective parts, using the equalizer correction. .Then test the microphone into different places, and then in turn transferred balance, change a few more positions, repeatedly adjust the equalizer to the frequency response curve of each region are as straight, even if the general tone equalizer good. . 7, dynamic control device regulation: General Dynamic conditioning is a pressure limit, pressure limit if it is chained thread in the system are generally used as a protection system, so the key is to use pressure .limiter clipping function. .Limiter settings I usually do this: pressure limit is set to direct (BYPASS), input and output gain set to 0 dB, the compression ratio is set to "infinity", and then send pink noise signal mixer, and gradually push the large, observed .amplifier's input level indicator lights when clipping (CLIP) lit. .Access Compression, adjust the knob to start the level, the amplifier input clip indication off. .Then increase the mixer output by 6 dB or so that the output level indicator to +6 dB, and then start adjusting that level, so that amplifier clipping LED flashes to the beginning. . Point, system debugging is complete, as for sound regulation and effective treatment (including the effects, actuators, etc.) are generally the task of the tuner. .Of course, sound engineering, which is normally provided by the company's technical staff to do sound. . .

【 Weak current College 】 speaker selection tips: Speaker of the shell material, volume---Power By 【 China power house network 】

Common multimedia speaker system is mainly divided into plastic speaker and wooden speaker. Plastic speaker than wooden speaker costs low, richer, but because it is disposable plastic, so the body has limited power is not very big.

Usually a Deputy X.1 speaker box power and size requirements for the use of plastic box. While most of the wooden speaker in high-density composite plate, thickness above the 1cm than plastic speaker has better anti-resonant performance and load more power, is seeking a more high quality people. However if the wooden speaker, wood density not very thin sheet metal and material selection is not good, the sound quality difference is also the same with plastic speaker. Generally speaking, the speaker cabinet is better in large volume, the heavier the box means that the selected sheet, the higher the more thick, density, anti-resonant performance better, in theory you can get better sound quality. Note that in theory, but does not exclude the special case, sometimes in order to achieve a different timbre or in order to balance the overall considerations, in the case of material choice breakthrough common also abound. In addition, usually larger speaker volume could theoretically increase the amount of bass, for low frequency effects more full, so volume relatively large speaker bass also typically render direct proportion.

【School】 how weak and flexible to use mixer equalizer.

mixer is one of the most important role in the modification of the sound, but now the mixing console (except high) tones are part of the three-stage equalizer almost without exception: high-frequency, low frequency re- .plus a frequency parametric equalizer, that treble frequency lOkHz or 2kHz, Bass 80Hz or 100Hz, some are labeled HI and LO in English for you to guess, but you guess the above parameters will be pretty close. .IF is the adjustable parameters, parametric equalizer for the frequency most people will use, and that align with the frequency of a frequency knob, then use the button above to boost or cut it wants. . But some careless high bass knob sound engineer was also the case law cook, to see the bass knob on the 80Hz or 100Hz think this channel is coming in what the electric guitar, that this frequency did not put it to use .to the left cut out, to see the lOkHz or treble button will toggle 12kHz spin to the left to think that this channel is electric bass can not, and this wrong, because it involves the three-band equalizer .characteristics of knowledge, in general, parametric equalizer mixer IF is a high Q, narrow-band bandpass filter, which is a characteristic peak frequency, frequency band is narrow, but the frequency can move around. . Used in conjunction with the sweep knob is a knob to increase and decay, while the treble and bass knob is a low-Q and wideband bandpass filter, its frequency curve is a scaffolding-type .and, therefore, the subject of 80Hz bass knob is its center frequency, which is based on 80Hz as the center of a region, its upper limit may be extended to 300Hz, while the lower limit may be extended to 20Hz. .Treble knob is true, 10kHz or 12kHz is also its center frequency, it is the extension may reach 16kHz, the next extension may be 5 ~ 6kHz, it is not indiscriminate all it decay or increase is extremely wrong, as it .is not a point you exterminate, but a sound area. .So sometimes the sound of the band feel thin, but can not find the reasons, then take a look at the bass EQ knob is in the over-attenuation position, and maybe that is the problem. . Addition to the equalizer but also have a button with the frequency that the gain in the number of buttons under the mixer will have a low cut button, which is actually a high-pass filter, generally indicated above, removed .frequency is 75 ~ 80Hz, it is said that when the button is pressed when the frequencies below 75Hz will be blocked out. .So when low-frequency knob is also work? .Of course, at work, it 75Hz still enhance the role of the above bands. . In the role of three-band equalizer is the biggest IF parametric equalizer, and it was a good thing, it can identify the need to address the frequency of the sound to make accurate compensation, in the high-end mixer .generally set the two IF parametric equalizer, one is HIMID high frequency, its frequency range is 600Hz ~ lOkHz, the other is LOMID low-IF frequency range it is 150 ~ 2400Hz, unfortunately only one console in general, it .The frequency range is generally 200 ~ 6000Hz. . Sometimes this kind of situation: a relatively thin singer's voice, which means about its frequency 250Hz for promotion to make his voice sound more full, but while his voice is not very bright ., also needs to improve his 2000Hz or so to give him more during their voices, then you will find a trade-off frequency parametric equalizer will simply not enough, then is not there a way to make your mixer a multi-frequency .parameters? .Can, then if your mixer has a direct output jack DIRECTOUTPUT it easy to handle, and generally direct the mixer is taken from the equalizer output jack after the pre-fader, and now you need from the singer channels .out a signal directly to the output jack, insert all the way to another channel, and now you have two IF parametric equalizer for your use. . You can use the first channel parametric equalizer compensation 250Hz, and then use another channel's parametric equalizer to compensate for the 2000Hz, of course, the first channel at this time do not push the volume fader, the sound from the .Road fader send, you can also send audio fader with the first way to make than the utility and the second way, of course, if you are interested, so you can get more IF equalizer, you can make more sound .modification, but there are two frequency parametric equalizer for embellishment on the singer's voice has been sufficient, if your mixer has no direct output jack, is not there way to get two IF parametric equalizer it? . Still, you can access from the singer AUX auxiliary output that signal all the way out, and then return to the other channels, the same IF you can get two parametric equalizer, the auxiliary output that is best for AUX1 fader .before, so do not push the fader from the road can be dealt with the signal to another way to continue treatment, pre-fader if you are the band occupied AUXl, you can also use the fader or post-AUX2 AUX3, .At this point mainly to the channel 1, first IF channel 1 parametric equalizer compensation 2500Hz, this channel-based sound, and then the other channel parametric equalizer to compensate for the frequency 250Hz, the sound effect modified push slowly, listening to .to the singer's voice can become full. . But note that this case is a two volume sliders to control the singer was somewhat inconvenient, of course, can also balance the volume of the two way mix of people after the grouping, which can be used to push all the way grouping .son. . Addition to the three-band equalizer, are there any way to the sound mixer to make modifications on it? .Then inserted INSERT jacks to use, and we know that this jack is very useful effects can be inserted, pressure limit, actuator, then the same here, we can insert a single channel 15 or even 31 band equalizer .sound device to be modified on the singer, how? . You simply can be adjusted freely to sound, but remember: sometimes self-defeating the modification of the transition, but the sound get very ugly, but here they give you a modified approach to sound only. .Another string in the main channel 31 band equalizer generally, in fact, there can also be modified for the singer sounds like your channel equalizer 2500Hz in the singer made a compensation, you can balance to in paragraph 31 .device is about 200 ~ 300Hz band can reach to make some compensation to enhance the effect of the human voice. . Visible mixer familiar with and take full advantage of the various jacks enable you to enhance the quality mixer, to get more sound processing means to make you work up even easier. . .

College】【weak corporate video conferencing systems in three popular techniques --- Power By 【China】 weak home network.

According to market consulting firm WinterGreenResearch forecasts, unified communications market development cycle is about to enter the healthy growth and rapid application stage. .2008, the market may achieve 15% growth in 2009 will grow by 30%. .The video in the enterprise deployment of unified communications will become an absolute dark horse. . Traditional enterprise video technologies include: MCU, H.323, Frame Relay, IP bearer network-based video applications, will push more features to the user's face. .But to successfully use these features, users need to focus on some new technology to give more attention. . An LPR: a steady video stream unified communications and video applications to enable enterprises to voice, data synchronization in the IP bearer network to transmit video data in the form of packets, which inevitably .Network packet loss problem encountered. .Packet loss will cause the video image mosaic; image local deformation, the screen refresh or flicker frequency; video and audio are not synchronized; frame rate drop, and image still other issues. .In the unified communications environment, as video, voice and data streams are transmitted simultaneously, thus packet loss will result in the overall audio distortion, interruption or intermittent noise, and the decline in the quality of content presentation, such as slides or fuzzy distortion .speed slows down page. .These issues will greatly influence the application of the user experience. .If the network packet loss rate is too large or too frequent, will cause excessive delay video communications, and even cause traffic disruption. . Packet loss is network congestion by the internal or external network priority traffic such as causes of conflict. .To avoid packet loss, we must first determine the bearer network packet loss rate, packet loss distribution over time, and video call performance of the various terminals and devices. . LPR (loss recovery) technologies to solve the current problem of video transmission loss one of the most effective way, based on the technology developed by Polycom, a new algorithm, its purpose is to protect IP video calls from .the impact of network packet loss. .In fact, LPR uses forward error correction is a (FEC) method implementation of covered packet loss mechanism. .Issued by the sender's data flow system to add redundant data, so that the receiver system to detect and correct errors without having to request the sender to resend the missing information systems. .This will have no need to wait for network transmission capacity of error correction, making the FEC is very suitable for real time communications, such as television broadcasting, IP telephony and IP video conferencing. . LPR works is ongoing through the video terminal to monitor all incoming call packet loss information. .Once packet loss is detected, the terminal will use three methods to ensure call quality: packet loss recovery (LPR), dynamic bandwidth allocation (DBA), as well as in the case do not support LPR, the use of traditional video error concealment ( .PVEC) technology. . Unlike most of the error concealment algorithm only involved in receiving or avoiding loss of information in a systematic way, LPR will be involved at all levels of the video call system, part of the call by temporarily assigned to a data channel bandwidth, ., which is used to send data to the receiver FEC to play a role. .Packet loss in network transmission occurs when a loop through the above, LPR will increase or decrease the size of FEC data channel, until you find the FEC data channel must be allocated to the minimum bandwidth, allowing the receiving system can recover all lost packets .. . When FEC data channel is larger than the standard value, the system will detect whether repeated FEC can reduce the size of the data channel, so as to audio, video and content data available to the call to provide more bandwidth. .Because LPR only packet loss is detected only when the occupied bandwidth, a feature that makes the LPR is ideal for random packet loss or sudden environment. . Packet loss rate against a relatively fixed network environment, dynamic bandwidth allocation (DBA) functions can be matched with the LPR. .DBA is an algorithm that can automatically during a video call, and dynamically adjust the video bit rate, to eliminate or avoid packet loss. .For example, in a 384kbps test video call to a stable at 10% packet loss rate, DBA will be reduced by about 10% of the video bit rate, from 320kbps down 288kbps or so, and then re-sampled signals, see if there is packet loss .phenomenon. .If necessary, DBA can further reduce the video bit rate, until no longer appear in seconds until the packet loss. . In reducing the rate, if the measured packet loss is temporary, DBA, DBA will gradually increase the video bit rate. .Conversely, if the DBA detects packet loss sustained, it is no longer adjust the video bit rate, but the call continue. .Therefore DBA applies to excessive use of network problems caused by packet loss or throughput environment. . The parties involved in the system calls the case do not support LPR, you can use the Video Error Concealment (PVEC) function. .PVEC is a quality of service for IP video (QoS) algorithms, which can be caused by the impact of packet loss compensation. .It is through the use of adjacent macro blocks, before and after the frame out of frame to estimate the content of the current video frame. .And LPR to recover lost packets and packet loss to avoid technical differences DBA, PVEC cover the role of the impact of packet loss. . On this basis, LPR allows the user to the error rate is high in IP networks (DSL, cable, satellite, high conflict, LAN / WAN, etc.) for high-quality video calls without the need bear lost .package impact. .Rate of ongoing calls by temporary adjustments, LPR can protect against short-term network video call problems. .Once the network problem solving, LPR will initiate the call rate or under the current bandwidth availability, automatically call back rate to the highest level. .This makes the network bandwidth can be fully utilized to achieve the recovery of lost data packets and transmission of real-time reconstruction of the smooth flow of audio and video data, eliminate waiting, intermittent, noise, confusion and other problems or information, but can reduce the dynamic jitter buffer .Spatial and related delays. . But the use of LPR will generate FEC channel bandwidth, which used video calls reduced their available bandwidth. .In the case of low-connection rates may cause a temporary reduction or resolution of the lower frame rate. . Two restore the scene: the experience of face to face clear video images for the user, the real requirement is no upper limit, which directly led to the Cisco TelePresence, Nortel and HP Halo telepresence .birth, as represented by these products, companies will use the ultra-high-definition video applications, technology, experience the effect of restoring the site. . With traditional video conferencing systems, these products are the most obvious feature is its ultra high-definition resolution. .According to reports, three pieces of telepresence using HD plasma display, each screen resolution up to 1080 × 1080p, than the current international standard HD resolution (1280 × 720p) twice, is 10 times the resolution of ordinary TV .. .6 people can provide "virtual meeting" telepresence 3000, required every plasma screen in the 2 ~ 4Mbps bandwidth between the 3 screens require a total of about 10Mbps bandwidth, ADSL has been impossible to carry the ordinary and therefore require special .Dedicated access or fiber access. .Ability to meet the ultra-high performance hi-fi images, and ergonomic design environment, so that Cisco TelePresence system can communicate in real performance of every detail, such as "clear white of the eye, skin, the hairs, and the communication of .strategy with a shy look, "and so on. .It is reported that net price is really 7.9 ~ $ 299,000, has been in AMD, Pepsi, GE and other large enterprises in the applications. . Emphasize HP's Halo studio system for enterprise remote analog face to face business meetings. .Connected by Halo, Halo studio support for each row of six people at a table, the second row of three to six and a maximum of 12 meetings of scale. .Each studio has three plasma displays, participants can see and I am the same size image. .In addition, participants can also use a plasma display mounted above the screen 50-inch collaboration with other Halo studios in its notebook computers to share files and data. .Photo Studio also includes a high-definition camera, the table can be used to capture and display the items on display in the collaboration, true color rendering, shading and nuance. .Equipped with a telephone for participants to work with Halo outdoor personnel. .Studio is equipped with broadcast-quality audio and lighting facilities, participants can use the simple on-screen user interface, start by clicking the mouse collaboration. .A complex software control system will ensure that all Halo studio easily and seamlessly work together. . HP Halo high-bandwidth, dedicated video switching independent network connection to provide full-motion video experience HVEN, making it among the world's Halo studio audio or video delay is not perceived by people. .24 × 7 to ensure all-weather connectivity, HP offers including: network operation and management, remote diagnosis and troubleshooting, security, equipment warranty and ongoing maintenance and repair services. .Halo studio users do not manage the operation and maintenance, HP has been present in 18 countries around the world more than 60 such workshops. . According to reports, HP Halo Collaboration Studios set of the room price was 39.9 million dollars, plus 24 thousand per month to 2.5 million in services. .At present, Halo users have included DreamWorks, Novartis, AIG Financial Products, BHP Billiton (BHP Billiton), Canon and other famous companies. . Nortel telepresence (Telepresence) communication system is fully reflects the "show" the mean, life-size screen, high definition video effects and StereoSurround sound seamless, collaborative display of multimedia content, videos and more .Point control technology (MCU) recording, archiving, streaming and HD support. .This is a more optimized experience can be customized, from small meetings of two people to be able to accommodate 28 people in the large conference room, users can achieve high definition video communications, and also show the film seamlessly, data tables, and other format files .content, collaboration, the equivalent of full virtualization of the people in the room to complete all activities. .And the whole process so far based entirely on meeting off-site environments. . Telepresence system, the modular design features highlighted; studio level lighting; professional acoustic treatment; no remote control and interactive control; hidden camera; microphone and PA system. .Every element is designed to integrate, fully embodies the technology seamless and transparent, and the organic integration of the physical environment to form a unified professional audio and video conference environment. .In addition to not shake hands, almost face to face meetings have been no different. . Nortel is really the standard turnkey far, Nortel provided a comprehensive set of services. .Including site survey, network assessment, project management, opening services, 7 × 24 hour support, and specifically for high-definition system MNOC multimedia services, both all-weather meeting appointment, proactive remote monitoring, meeting to establish, confirm and report monthly remote services. . Three QoS: high-quality transport protection application of QoS in the network technology is not new, but the video QoS bearer network streaming media technology is a new hot spot. . Business-to-video technology innovation is the pursuit of the application of streaming media technology to become mainstream. .Streaming real-time playback, there are strict requirements, require a specific time interval to decode a particular unit of data display. .Streaming media business development at present there are some problems, such as playing media files, pause, mosaic and so on, there are a large number of users to access popular content sudden server processing difficulties, etc., these problems are related to the QoS of streaming media to ensure .. . Enterprise Video used in the most critical business, but also with voice, data synchronization, transmission, network transmission quality and therefore have higher requirements. .QoS needs of streaming media to solve two problems, bandwidth and delay jitter. . We all know, video and voice networks such as unified communications is one of the applications the bandwidth consumption. .Bandwidth limitations on the one hand affect the quality of video playback; the other hand, consumption of large bandwidth streaming media applications, will work with other businesses in the network compete for bandwidth, which of these affect the normal operation of the business. . In addition, IP network for video data, store and forward mechanism to determine the packet delay and jitter is inevitable, so the streaming media transmission, the end to end delay should be controlled within a certain range. .Streaming Media QoS using advanced video coding scheme, video data compression to improve efficiency, as much as possible to eliminate redundant information in the video, making the source code as little as possible the amount of data output, the minimum network bandwidth to accommodate the situation .. .Meanwhile, video quality can be graded to provide a flexible adaptation to maximize the dynamic characteristics of the network as far as possible to provide users with better video quality. . Scalable coding techniques to increase the coding output bit stream to adapt to dynamic network bandwidth flexibility, multimedia data compression coding into multiple streams. .One can be independent decoding, known as the base layer bit stream, the other is called the enhancement layer stream. .They can not be decoded separately, but only with the base layer and enhancement layer before it is combined with the decoder, used to improve the viewing experience. . .

Weak current College】【mixer of use --- Power By】【China power house network.

When you first contact a mixer (especially the simulations of the desk), can easily be it panel presenters, a large number of knob and push rod swindle, in practice, however, per the significance of the push rod and knob is the same, so you only need to focus on understanding a channel operation method you can acquire a mixer of overall use.

Fewer branches of mixer with 4-channel and 8-way, way up in a 96-channel even more. A mixer for a per control consists of a master and secondary control of two parts. Auxiliary signals has a separate output can be realized in the same sound mixer can also output two sets or more mix signal.

Each channel has one or more specifications of signal input used to connect the system's sound recorder, audio sources, sampler or synthesizer, audio output, or plug in the circle, capacitor microphone, etc.

And these inputs of the next-door is usually a knob, we call it gain knob (trim), is used to adjust the amount of the input signal, that is, when the signal is too strong when it cuts, too weak when you upgrade to their (sometimes gain knob will be an attenuation of the button instead of the "pad", when the button is pressed or when the input signal up is to do a certain amplitude attenuation). Gain knob is as sound input mixer of the first gate, adjusting the fit, to guarantee the sound mixer next level of processing circuit can receive a full and "clean" signal.

When the gain knob set up later, you can use the channel volume faders (or volume knob, usually located at the bottom of the Mixer Panel) to determine the channel signal is sent to the size of the volume. Volume faders is actually a attenuator for on the channel output signal attenuation. When the bottom-most faders (or volume knob located on the left-most), signal attenuation is infinite, then the channel no signal output.

In volume faders of the above, you can find a sound like (PAN) knob, which is used to adjust the channel signal between the left and right speaker stereo position.

Some table in volume faders and sound like a knob design also between two buttons: mute sound (MUTE) and solo (SOLO) button. Mute sound button can be dynamic volume faders to the mix bus in the channel's signal to shut down. When the channel output volume has been fine-tuned and don't want to touch it again, this feature is very useful. When the solo button is pressed, then the other solo button was not pressed by the channel does not make any noise.

The vast majority of mixer provides a certain channel Equalizer function. A lot is not very professional mixer provides are segmented balanced function, reflected on a mixer is labeled "treble" and "bass" two knobs, when adjusting the two knobs at higher and lower than the manufacturer intended frequency of the signal that is being promoted or attenuation. The above is also commonly referred to as a two-stage balanced, and the third paragraph is more of a balance on the frequency bands (mid) to upgrade or attenuation knob. Other mixer also adds a select intermediate frequency point of knobs, we call it a semi-parametric equalization, and all intermediate frequency parameters if balance not only to selected Central frequency but also can select a frequency range to improve or attenuation.

General sound mixer for each channel are designed for 2-6 aux send (SEND, also called effect send) button. These knobs to control the channel signal is sent to the secondary output (AuxSEND) semaphore, several channels of signals can be supplemented by secondary dial out to a secondary port. When the auxiliary outlet connections after the effects, from auxiliary port output signals through effects processing, the effects of the output returned to the secondary return input mixer (AuxRETURN), and then blend with bus signals.

Control the amount of auxiliary signal returns knob General are arranged in a mixer control section on the right side of the bus. In live recordings, the auxiliary outlets can also be used to connect headphone amplifier for multiple listens to music while the singer.

For multitrack recording system designed for large-scale mixer each channel has a tape/line (Tape/Line) switch. This switch can determine each channel input source is microphone/line input source or multiple Rails machine's rail-independent output. When a multitrack audio recording, this switch should be placed in the line input status; sound recording is complete, on-rail signals contraction mixed, the switch should be placed in the tape input state, then the channel faders is actually the regulation more rail-rail signal output to the stereo bus semaphore.

The mixer has its channel in addition to the above mentioned enter the estuary, there is also a breakpoint insert (INSERT), used to connect l/4 \ "stereo plug (divided into head-Tip, ring-Ring, sleeve-Sleeve of three parts). When the mouth is no plug, the channel signal according to the above process with a mixer sections are processed; when there is a plug, the channel of input signal is disconnected, the plug Tip parts sent to external effects, treated by the Ring part back to the channel, and then gain, balance, sound like, volume, adjust the final output to a mixer's stereo bus. Like actuators, compressors, etc generally use this way to connect with a mixer. This way you can make the effect is only a certain channel signal processing without having to use effect send and return control.

Ultimately, the channel output signals mixed together, and then enter the stereo bus. Bus control part usually have control left/right channel of two (or a) master volume faders, adjust the effect returns quantity control knob, Headphone volume control knob, the output of the secondary output volume control knob (secondary output output signal is part or all of the channel's mixed-signal). On the secondary output of various flexible use, no space to do more to explain.

A mixer will typically have two or more VU (VolumeUnit abbreviation, which means the volume indicates) indicator. Some indicatorsThat kind of old-fashioned pointer table, the LED (light emitting diode) level table. Some sound mixer you can switch on indicator displayed with a different bus and channel level; some are designed for each channel and the bus has its own VU meter.

【 Weak current College 】 projector DIY dusting yourself---Power By 【 China power house network 】

Jiujingshachang projector, three years of use for a long time. Therefore, find white screen with light blue colour, brightness seemed worse than previously. Search the Internet, to your friends ask, answer because basic lock in LCD panel product with dust particles, optical path there are clearance. After you get the machine to the vendors there, the view, the warranty period has expired, to clean the machine, it will take hundreds of large element. It is not expensive, but there's nothing like it seems complicated, simply do it yourself.

First online to find some information, determine the practical steps and considerations, the projector off on bunks kailian (of course, when the purchase price is more expensive projector remember don't imitate).

Basic operations: open the enclosure; confirm LCD module position; the LCD module 3 unit cable (red-green-blue) for off-this step is the most critical, be careful not to damage the wire and contacts; release circuit board, remove the plug; set LCD module, remove the circuit board.

The module in the light of observation, it turns out that a lot of black dust scattered; first with cotton stick, wipe the LCD Panel of the dust around the powerful gas blow away the dust adhesion is not strong. Now clean, but also stubborn dust, with lens paper stack growth, dipped in a pure water and squeezed dry to slip gently wipe the head, the dust removal from the Panel. Panel will have a small amount of water-damaged, do not cares, as long as you confirm the wipe clean. Panel and the gap between modules is also dust, wipe the lens paper can be folded into the long wear in the past, taken away from the dust, and generally do not have to remove Polaroid. Finally get gas blowing and then clean up again, restore the installation can be.

The most important considerations is careful, for the first time after the restore, Cawan may plug a cable is not tight, picture recovery after a movie, and replace it again before it can get.

Operation is very simple: have the practical ability of friends you can try, basically if you use more, like dust environment comparison of city, 2 years of use, will certainly require dusting. In addition, DLP optical machinery is sealed, in this context will have inherent advantages in selecting DLP technology projectors on dust concerns will be less.

【 Weak current College 】 smart meeting room system design skills

Often some contractors doing programming training, often are asked how the smart conferencing system design issues, as well as conference system equipment selection, based on previous information, set out the following points, and they share.

First: analysis

Mainly analysis of customer needs and how you want to reach, as well as the cost of function, how to boot the client at the same time.

There are the following:

1. make feature 2. scene arrangement 3. Design highlights 4. upgrades and extensions for ease of maintenance ease of 5.6. cost
Obviously, the analysis to the design, the design is based on a function. According to user needs, identify the functional requirements, depending on the features to build the entire system.
Therefore, the design should take the following aspects:
1. the customer on system needs 2. composition of the entire system 3. subsystems function and composition 4. equipment selection (5) equipment listing 6 £ ® system connection diagram 7. system implementation
Thus, we can see, depending on the features to build the system requires to carry out functions of the entire system, only every single function, and finally to achieve full functionality of the system. We call this system breakdown: System — subsystem — device — functionality.
Thus, we can start with the functionality from the system, a system needs to be functional, the General Conference by: meeting room; remote video conferencing features; stereo; display; photography; signal management function; camera tracking; centralized control function; the part
A, room Conference features: discussions, voting, simultaneous interpretation
Thus, we can very easily to the required equipment selection, set out the following list of equipment: digital conference host; digital Conference unit; unit of digital Conference representative; infrared emission host; infrared emitting Panel; infrared receiver unit; translation unit; wired simultaneous interpreting units; wireless Division hosts; wireless voting terminal
Second, remote video conferencing features
Unavoidable, in order to achieve remote video conferencing features, remote video conferencing Terminal established to achieve this functionality of equipment, we can choose according to needs and matches the device.
3. Audio: 1. mixer, equalizer, feedback, etc. 2. amplifier 3. speaker 4.DVD, LCD
4. display features:
What kind of devices can be used as a display device, in our daily lives can be easily met, for example: DLP Projection; LED;; monitor; electronic table card ... And so on, which, in the device list we can choose: projector; electric projection screen; LCD TV; electrons table card host; desktop display unit, and so on device
5. camera features: this section, we will think of incontestable: camcorder or camera these devices, or other video capture devices, therefore, in the devices list, we can use some of the manufacturers of the camera, for example: macro-control camera
6. signal management: AV matrix; VGA matrix; DVI matrix; distributor; RGB matrix
VII. centralized control functions: achieving the effect of centralized control, the Conference Room of light, sound, signal switching for centralized control, and can reach wireless operation!

Equipment list:
Central control of the host (such as: KT-MC2); wireless touch screen; power controllers dimmers; volume control; infrared emission rods
Above, we have adopted the functional requirements, determine the device. It raises various subsystems of the frame, and then through the central control system, the subsystems organic orderly and rational connection together to form a complete set of intelligent conference system.
Then, the system establishes down these things, we should do a training on the product, as well as implementation.
Product training.
1. famous brand;
If you selected device brand is famous, in which the industry awareness ishigh, will give you market on the convenience of the promotion.
2. high performance-cost ratio;
The price is a sensitive issue, but as long as we provide products is good value for money, you can take to walk there. The user is very willing and ready to buy such products.
3. the manufacturer of comprehensive strength;
Manufacturers have strong comprehensive strength and can provide very strong backing.
4. manufacturers to provide support and services;
Support: can price support, technical support, staff support and other services: after sale.
Implementation of the
When we have the equipment and programmes, also know the installation location. Next step is to consider the approach implemented. Overall, do the following:
1. wiring requirements:
Strong, weak lines separately;
Power and signal cables separately;
Power supply and control cable separately;
All conductors must wear pipe laying;
The entire system with a unified power distribution box, so as not to produce power interference between devices;
At high pressure and high magnetic field and other harsh environment, you should choose the shield line; in a humid environment should use sheathed cable.

Weak current College】【how to select the speakers --- Power By】【China power house network.

The speaker is actually a put to wide audio power signal transducer (loudspeaker), put it into enough sound pressure level of the sound can be heard. To correctly select a good speaker, you must first understand the properties of a sound signal ., and then ask the speaker to the "authentic" and audio signals into realistic nature sounds. The human voice and the music is a random signal, the wave is very complex. You can listen to the sound frequency range usually ranging 20Hz .-20kHz; language of the spectrum range around about 150Hz-4kHz; and various music spectrum range up to around 40Hz-18kHz. Its average spectrum of energy distribution: bass and bass parts most, some times in the treble, the treble section minimum ( .about as part of the energy in a, bass 1 / 10); the energy of the human voice is concentrated mainly in 200Hz-3.5kHz frequency range. They can listen to the sound random signal amplitude peak average than it is about big 10 - .15dB (or even higher). Therefore the speakers to correctly release these random signal again, ensure the replay sound sweetly, speakers must have broad frequency response, enough sound pressure level and dynamic range of signal. We hope to .be able to use relatively small signal power input gain enough sound pressure level, requiring the speakers have a high-efficiency power conversion into a sound pressure sensitivity. Also called speaker system in the input signal is just the right amount of overload, would not be .damaged, that is to have a high reliability. Speaker system the main technical characteristics of the application: The speaker system has many and tone effects and applications directly related to the technical characteristics, in .order to make the best use of live these technical characteristics, the user must know something about them. 1) 2nd Road (second Division) and three-way (three frequency) speaker system .Audio signal spectrum range is wide, the 20Hz-20kHz signal to a speaker unit is unable to meet the whole length frequency response; more than average 12 inch large diameter speaker unit, bass performance is very good, distortion is not big, but more than .the signal, it 1.5kHz behaving badly; 1-2 inches of the treble speaker unit (treble compressed drives) replay 3kHz above signal performance was good, but cannot replay baritone and bass signal. So they have a frequency response from the various modules of .the speaker system, the bass (bass) and treble (treble) made up of two units are called two-channel speaker system, bass, tenor and treble three modules known as three-way system. 2-way .speaker system structure is simple, and relatively low cost, in order to address the lack of audio in this paragraph, then the rate of manufacturers with a folding failure, that is in the crossover network on bass unit of frequency response up to treble unit waiting .to move down the frequency characteristic. Another problem is that the crossover frequency can only be set at the intersection of 500Hz-2kHz regional, and this is what the human voice and the music is an important part of the spectrum. Therefore in the hearing on .the left are "empty" and hear distortion. Also because of this, three-way speaker on driver demand relatively high, if the unit's performance is poor, the voice of the speaker system is not smooth, or have serious phase distortion. 3-way speaker system unit characteristics may not compromise, giving full play to their strengths, the intersection of the two frequency in the Alto voice and optional music spectrum important parts of the upper and lower edges, has no effect on the .sound quality, 3-way speaker system reduces sound distortion, raised his voice clarity, improved low high and treble cross band performance, increase the power of the speaker system, so the processing power is theatrical performances, concert hall and Opera House, the best .choice for sound reinforcement systems. 2) sensitivity and maximum sound pressure level (SPLmax) Speaker unit is a form of electrical signals and sound between the transducer and request it to be relatively small input .power conveyed into a rolling sound, this requires that the speaker has high sound pressure sensitivity, [sensitivity] is essentially a [conversion efficiency], plus various Yang losses due to the use of the system design, selection of materials and production processes, and .other aspects of difference, sensitivity are large. Sensitivity refers to the input 1 Watt loudspeaker unit power, leave the speakers axis 1 m distances measured sound pressure level, if the sensitivity of the two speakers differ by 3dB to achieve .the same high sound pressure level output, you need to increase the electrical input power is doubled, so sensitivity higher speakers can make a considerable amount of sound. Speaker system input power capacity is generally much greater than 1 Watt ( .generally at 100 Watt-2000 watts) therefore actually used can enter the maximum permissible power for the rated maximum power, type speaker, speaker axial 1 m resulting sound pressure level is called the maximum sound pressure level SPLmax cases, sensitivity = 100dB, 1w / .1m speakers, with maximum power capacity to 1000W, SPLmax = 100dB + 30dB = 130dB, 1m. 3) distortion and sound quality Speaker factory have nominal rate distortion of their products, in fact .it is a very important technical parameters, quality is a relatively abstract evaluation, there is no possible in superscripts, only the file take subjective listening test, usually, the sensitivity and the sound quality is contradictory, manufacturers need to strike a proper balance in, .generally speaking, the price of the product, are driven by sensitivity, the pursuit of cost performance, and high-priced product-neutral sound quality, and the highest level is a combination of both. 4) [character .] and [common] In this once again cited out another relatively abstract and subjective evaluation of audio, sound reinforcement, unlike at home of Hi-Fi audio equipment, have compatibility is very high, because each site may show .different types of programs, from Opera to rock concerts, Also possible is to report the signal-based language, so the sound system must be compatible with the different program source, do [average of] the superior is not biased to a particular one and .home Hi-Fi audio equipment, only need to take care of a person or a small group of people, their product is to allow the [character] exists, but as a professional sound reinforcement systems equipment, the [character] will become [limitations .], or [defect]. Professional sound amplifying equipment needed for a large group of public services, programme content often transform, [General] are the basic requirements for a stronger, compatibility, different kinds of programs must have .[average] performance, in addition to this, the professional sound reinforcement equipment must be "no rendering", "no exaggeration", "true" to restore the sound source is [common] or [common sexual]. 5) speaker system point to properties The speaker sound is usually in the low frequency band (below 200Hz) voice is not directional, spread evenly in every direction, but in the high frequency band, the sound propagation render .strong direction, this points to a character (various speakers are not the same) is what we in the system to be applied, the excellent characteristics of constant to point to the site layout when Sonic Energy focus to the audience area, avoid strong reflection surface .acoustic wave and acoustic field interfere with each other. The speaker's point to properties that deviate from the axis of the sound pressure level with the deflection angle increases gradually decrease the sound pressure level, sound pressure level and with Sonic distance .increases as the square of the distance and decay is inversely proportional to the distance from the speaker and the position of the different audiences district, will select the two attenuation, you can make the proper two kinds of decay mutual compensation, thereby enabling a more uniform .sound field, large projects need cover relatively wide range, single-only speakers are often inadequate to meet the needs of the many speakers spell synthesis speaker Group (display), and in the display speaker system, the Hang Seng index to feature allows speakers between .medium and high frequencies of sound waves in the speaker room do not produce mutual interference, use the above links to properties with a pair of speakers is composed of eight glyphs display, you can override the individual speakers, otherwise, the sound in speaker front already .interfering seriously affect the sound field of uniformity and clarity of the sound. 6) speaker system power handling capability Speaker power handling capacity (or the speaker of the rated power) is an important parameter .that represents the speaker stand long continuous security of power input capabilities to understand the speaker's power handling capability, you must first understand how damaged speakers drive, drive damage model has two kinds: One is the voice coil heat damage ( .voice coil burn, overheating deformation, circle room breakdown, etc.), and the other is drive diaphragm displacement exceeding limit values, so that speakers of conical diaphragm / or its surrounding elastic part is damaged, often containing many large amplitude and low frequency signals .. The sound signal is not a sine wave signal, but a random, these random signal available three can count to indicate that a valid value (RMS) also known as RMS value is to signal peak amplitude sine signal measurement .results, close to the mean, basically, on behalf of the signal of heating energy. Peak (Peak) is the signal reaches the maximum level, for a sine wave, peak level greater than valid values for the music .signal 3dB, peak level valid value of up to 10-15dB in assessing a speaker's movement capability, the peak is important, crest factor, used to illustrate the peak and RMS level of the ratio, for press AES2-1984 pink noise source, crest .factor, for 6dB peak voltage is 4 times the RMS voltage. Speaker power handling capacity by (AES2-11984) of pink noise signal continuous plus 2 hours of work, its electrical and mechanical properties of permanent change of not .more than 10% of the measured parameters. 7) load (heated) after the sound pressure level (also known as power compression) All product specifications are marked that power all manufacturers of custom .is speaker at the manufacturer selected test signal and the best value under the conditions, when the speaker into the work status (for example, equal to or greater than the full power of 20 seconds), voice coil and magnet heating temperature rise after, because .of their performance has changed the original heated front unit characteristics, this time, the actual sound pressure output will reduce, conventional speakers, such as voice coil temperature 60 ° -80 °, common rating sound pressure drop 3dB for tolerance, such as the excellent .voice coil cooling, temperature up to 100 degrees or more, the actual sound pressure drop of up to 6-8dB, this is very alarming decline, such as former titles and a doubling of the speaker only enhance the sound pressure level 3dB if speaker sound .pressure level dropped to bridge up to 6dB, so much sound pressure level must be reduced from the original one speaker increased to four, sorry, audio industry not nominal decline such a sound pressure level, you must close to improve the thermal design of loudspeaker unit .. 8) speaker cell impedance The impedance loudspeaker unit including, inductance, capacitance and resistance, inductance and capacitance changes with frequency, while winning the speaker system that an impedance changes too large, it .will affect the stability of the entire sound system, JBL's new DCD double coil difference driven design is the impedance becomes [pure resistance], are not affected by changes in the frequency, the entire sound system stability. How to .improve the reliability of the speaker system In daily life, even in the amplifier and speaker system power matching certain circumstances also occur in young cells become damaged, losses plus, their reasons are: 1 .. improper operation, power amplifier output power is too large 2. show climax when a warm atmosphere, the need to enhance the sound pressure, increase the signal, the microphone input signal too much cited amplifier overload clipping, a .large number of harmonic distortion of waveform generation, and damaged the treble unit 3. microphone strong acoustic feedback whistling, PA strongly damaged speaker system overload, as this isGeneration of a new speaker system to take a variety of protective measures ., these measures can be divided into two categories: 1. improve the thermal power loudspeaker unit so that it does not occur when the overload, overheat damage 2. the speaker box install limiting protection .device, when the motor power and peak over the speakers of the ratings, the limiter to exceed the power level using a nonlinear resistor (bulb) to block the voice coil. These measures increase the capacity of the speaker on .overload, but also influenced the sound of dynamic range, the range is wide, timbre feel fuzzy and bleak. Therefore, the best approach or amplifier measures so that its output is not generated clipping and power overload etc. < .br>.

Weak knowledge of audio and video