】 【Weak current College (go) expert detailed professional audio troubleshooting tips (6) --- Power By】 【China power house network.

<br> (VIII), professional audio Exciter: audio actuator is actually a harmonic generator, use one of the psycho-acoustic characteristics of sound signals are decorated and embellished by an audio processing devices. Following that when using the actuator under need to pay .attention to some issues and actuator is prone to failure: 1, although theoretically use good actuator can enable increased loudness sound system, while at the same time signal 10dB output level and system output power is not too much change, but we still do not carry .excessive actuator tuning, or they may damage the amplifier and speaker device. 2. the actuator IN / OUT in comparison with and without the incentive of sound effects, many sound engineer can't distinguish sounds the subtle differences, because the speaker out of voice .rarely direct radiation to sound normal ear, so pay attention to when adjusting to the effects of acoustic venue to listen, brazenly chaos tune may cause sound weird, microphone transfusion, serious damage to the device when you also. 3, there are some of the .acoustic field smooth reflection area because there are too many in the treble of the sound system is powerful, sound reflection is also very noisy, and if you then join the actuator "penetrating" is even worse, the treble will become more harsh, loud, .acoustic feedback may become unmanageable, and therefore, better sound field is very important, nor is any sound field using actuator. We can see that although the use of universal digital processor is a trend, but now the digital processors rarely with incentive function, most .are: balance, compressor, crossover, delay, and equality. As a result of high-quality audio actuator in quite a long period of time or irreplaceable. <br> <br> (IX), amplifier and speakers: what is a power .amplifier-what is speaker I am not here to explain, here's that use power amplifier and speakers are required to pay attention to some problems and failures of these devices is easy: 1 match: generally speaking, the power amplifier power than speaker power, normally .amplifier power than the speaker's power 30% or more, if you use small power amplifier to push power loudspeaker, amplifier easy overload, will produce the sound of the current, the driver can easily be damaged. 2, impedance matching: current professional audio systems .using amplifiers are generally fixed resistance, general power amplifier at 4 Ω - 8 Ω work up some audio masters like one amplifier push 2 more speakers, and then note the speaker impedance, many speakers and parallel impedance decreases, if less than 2 Ω is .that this power amplifier is easy to damage the approximate short-circuit mode it is best not to use. 3, power amplifier and speaker line connection between: amplifier of signal cable to use balance line, if your system has more than one power amplifier, .it is best to use signal amplification splitter divides into number enough, there is no attenuation signal cable supply each amplifier is used alone, this can reduce system noise, reduce risk, improve the SNR. Also note that the speaker cable quality and connection, as .far as possible with relatively thick, short of the speaker cable connections must pay attention to distinguish positive and negative and avoid short circuit, especially the major four-core or quad-core above speaker plugs, several terminals is very small, it is also important .to note that the wiring. 4. power amplifier behind sometimes many transfer switch, such as: mono mode, stereo mode, bridge mode, as well as the sizing of a level switch and signal frequency switch, etc., we use must be taken .to see these transfer switch, the power amplifier adjustment to correct or you want to work, otherwise it may cause unexpected failures. Amplifier and speaker fault example: 1, 05 at Shanghai DJ contest audio equipment, our engineers said the bass is not enough, .looking fore, I saw all the Bass Amplifier 130Hz low cut switch is turned on, the following are the bass 130Hz excision, in this case there can be no satisfactory nature of bass. 2. once I a disciple in an outdoor performance, system of .a total of four power amplifier, 2 QSC, 2 old masters of the United Kingdom recorded, signal lines through the amplifier rear input and output interface to convert distribution, according to the normal, formal approach to the entire system of power lines and signal cable .is connected, turn on after system how did not sound. I used to have a look at mixer correctly, other former grade equipment is also no problem, then I put the audio signal separate input to QSC power amplifier and a voice in the speakers, .a separate input to the old master of United Kingdom audio amplifier speakers also have sound, but when two amplifier via the signal cable is connected, the two amplifier driven by the speaker, all of which have no sound, I look at the discovery of the .old masters of United Kingdom audio power amplifier with XLR card Lennon interface, 3 2 for the hot end, for the cold end, 1 = GND, and QSC and most professional amplifier behind you "connector XLR card 2 to 3 hot end, for the .cold end, 1 = GND, because the signal port standard and standard, when the two amplifier of signal connections together, essentially equal to short-circuit, audio system, won't have a voice. Then I put the sound mixer 2 road in .the main output signal to the QSC power amplifier, mixer 2 ch marshalling signals to the old masters of the United Kingdom recorded amplifier, the system is normal. Of course, I later discovered new audio guru power signal port is also adjusted to: 2 to .3 hot end, for the cold end, 1 for grounding. In short amplifier and speaker system is the system in the last two devices, the preceding is all peripheral equipment and services to them, in a project, can correct and reasonable connection configured amplifier .and speaker, that the project is half the success. <br> <br> Fourth, the device itself fault current professional audio equipment and most are very ripe, general import of equipment under normal circumstances are rarely failed, but some domestic equipment relative to .the device itself failed to comparisons, the following will introduce the professional sound equipment of common fault itself: <br> <br> (A), the mixer often own fault: 1, volume faders contact is not good, the sound is choppy when .working. 2-channel input port failure, such as previous old-fashioned Budweiser mixer of XLR input port card you can easily "uprooted", began to encounter this soWhen I really obstacles could not believe my eyes. 3. control system disorder, one .time use a sound arts 16-channel mixer, and found that total output no signal, then later he changed to group the output, and so on down the marshalling and no signal output, but I pushed the 10-Channel faders, went out to .do sections 11 road channel sound. Then I went through the AUX output signal, and so on, finally this mixer or thorough strike. At this point is the performance cannot silence, I simply put the CD signal directly to the power amplifier and drop some .music. Failure of a mixer like this for so many years I also met for the first time, it had not heard of before. In short a mixer of fault simply enter part, output, control part, power part and so on, are typically .caused by aging. <br> <br> (Ii), Equalizer common own fault: 1, Equalizer sliding key contact failure, this is the most common, mainly due to aging and bad environment. 2. Equalizer inner line fault, I ' .ve seen some Equalizer only one signal output, later discovered that all the circuit broken, but this equalizer, I met several times. <br> <br> (Iii), compressor, electronic dividers, professional feedback suppressor, professional fault delay unit common .itself: these devices in addition to the severe aging equipment is generally not a big problem, the best is the adjustment knob and back panel signal Jack a bit small. <br> <br> (Iv), digital effects common fault: 1, .noise, digital effects when processing audio signal itself has some digital noise, if combined with the shielded signal cable is not good, serious noise like rain. 2, digital effects of core part is digital processing chip, the digital chip has failed, I saw .one YAMAHA500 effects, able to splash but does not work, there's no way to adjust your all and so complex digital chips also didn't approach to maintenance. <br> <br> (5), amplifier and speakers common fault: 1, .power amplifier for most common failure is bad capacitor or burning power amplifier tubes, which we use, but most of them were not stable on the device itself. 2, then I also found some amplifier occur a channel no sound of fault, or inside the .circuit. 3. as regards the other fault what amplifier volume potentiometer contact is not good, left and right channels are not balanced, protection features are too frequent, back panel work transfer switch contact bad and signal Jack, in short, the power amplifier is .now sound system easier for failure of an electrical device. 4, speakers section of the fault of the most common questions is, of course, the Horn can be said to have a sound system in the most vulnerable to failure is burned Horn, this of .course, some people are factors, but most still sound quality problems. 5, speakers of another common failure is the wiring port aging, bad, and in particular the regular flow of speakers vulnerable to this kind of failure. Above these devices themselves failures generally .sound engineer is no way to repair, in the previous article I said, the audio Division to achieve the "professional", if what power amplifier is broken, Horn bad those are maintenance engineers, our sound engineer's job is to match a good sound system ., the various sounds good, doesn't have to be jacks-of-all-trades! <br> <br> 5. interference <br> <br> (A), power interference: 1, lighting system and sound system power .separately to avoid lighting system interference to sound system, which in the previous article said. 2, lighting and sound systems do not use power when the grounding of the ground, making his own professional electrician according to standard play lightning rod two ground, one to .the lighting system, you can add in lamp and lighting console; a ground wire to the audio system, the use of satellite-ground method, these measures have the lighting on stereos of interference to a minimum. 3, of course, in addition to .the lighting system, sound system of its own power but also minor interference problems, such as switching power switch when the power pulse may cause audio system issued slight sound pulse. I used the night wearing headset operation mixer, on several occasions he heard the sound .mixer are radio voice, of course, these should be the power interruption. <br> <br> (Ii), the wireless signal interference: interference 1, wireless microphone: poor wireless microphone can interfere with other wireless microphone, wireless microphone signals are .also vulnerable to other wireless signal interference, so the wireless microphone is used to pay particular attention to these aspects. 2, cell phone signal interference: such interference occurs frequently in singers singing with a wireless microphone, the singers of the mobile phone if you call ., the phone signals may interfere with the wireless microphone signal, resulting in the sound system makes a lot of noise, so the formal performance actor is not allowed to play with the phone. 3. other some such as radio and other wireless communication devices, .radio broadcast, wireless receiver and transmitter systems, electromagnetic systems has the potential for interference to sound system. <br> <br> (Iii), drive interference: there are some bad DVD or VCD player easily through the signal line interference, leading to .a mixer mixer produced more serious noise. In short, sound system fault is the variety of interference, the cause of the failure is a variety of electronic devices, as long as it is, you can't completely avoid this interference, we can only .try to avoid. <br> <br> Sound system interference fault example: 1, 1994, friends say their new ballroom serious leakage, and lights up when the sound is loud. I went to the multimeter measured the following leakage voltage 380V even up .! I estimate should be lighting system leakage caused by construction, that time is far from this place, audio and lighting is in use all the way to total power supply 380V, and at that time light system like the sharing of all the Earth, is .to turn the light on most of the lights of Earth together, so you can save a lot of wire and, of course, this is not safe is not standardized. Know the circumstances, I would allow the electrician from the Ballroom outside hit two ground ., a connection to the lighting system, a connection to a stereo system, and leakage failure and troubleshooting audio interference onSolved. <br> <br> 2, 02 friends made a large Opera friends while I said to the lighting and sound are respectively the .ground, but the audio system noise or it is obvious that acceptance is certainly is a gateway. But friends say there is not even tap mixer is set, only the total volume is noise. I put the sound mixer 30 multi-path signal input line .-by-case basis, when unplugged to 27, 28 two road stage microphone line in, found the noise is gone, to prove that the two lines is the noise source. Friends say that these two lines is the stage outside of the 2 - .way stand microphone cable to the stage where I knew the reason: the original of this stage of the framework are all made of metal, the lighting system is through these metal frames are connected with the stage, and the two-channel microphone cartridge is made .of metal screws on the metal frame on the stage, which is equal to the interference of light through the microphone cartridge into the mixer, the cause of the malfunction was found, so I let my friend took the microphone cartridge screws removed the direct use of .glass plastic took the microphone cartridge pinned, glass plastic is insulated so that failures are excluded. <br> <br> 3 International Convention and Exhibition Centre, in a city, a Committee in a meeting, the Mayor of the podium was about to speak ., the speaker was suddenly issued a thunderous noise, the leadership was present here, and then be shocked Halo nor had left. We can imagine leadership angry very serious consequences, where technicians how to find the cause of the failure is not found, then I .went to the understanding of the situation, and probably knew: the original day meeting rostrum is used by the wireless microphone, when Mayor walked to the top floor, the light in relation to fight off the rostrum lighting, sound engineer took the road, wireless .microphone, who knows at this point the system suddenly makes a lot of noise. My initial judgement should be lighting system, wireless microphone signals interfere with each other, and then follow the day of the exercise was repeated many times, my judgment is correct. .I let the engineers back playing two ground respectively, lighting system and audio system, and then put the rostrum with Silicon case control lights the way power alone, while the other has increased by three primary colors, and other meetings with cold light sources for lighting ., additional rostrum wired Conference microphone, later important meeting as far as possible with wired Conference microphone sound reinforcement, after all, wireless or not assured. From then on there was a lot of major international conferences, large performance have not appeared serious interference. At .this point that the professional sound system troubleshooting article all finished, because the sound system of failure, fault causes are more complex, so this article is not exhaustive of all the audio system set out in trouble, I simply wrote down the sound system in common .some failure and troubleshooting and examples that hopefully will help!, because of the limited level of inadequacies, also at colleagues and experts correct me! (China audio engineer Association senior audio engineer Liu Hua) <br> <br> <br>.