【 Weak current College 】 car audio use or installation of technical knowledge---Power By 【 China power house network 】

Host is the most familiar with the majority of audio equipment, the host of various performance and specifications, and is familiar with the matter, the following are some of the use or installation, more things to consider: LOUDNESS: host a few years ago, this key only to increase the bass part, so called "bass enhancement", the vast majority of hosts not only enhances the bass, or enhanced, thus the "loudness compensation" is the more appropriate term. Because the human ear, whispered, treble and bass later meal (FLETCHER MUNSON curve), loudness compensation function will make music more appealing, however, when the volume is large, unless each speaker has appropriate protection of the damper, horn is easily broken. Grounding problem: most of the host of design, the Horn of negative power cannot be exposed to the negative (i.e. the car shell), so be careful when you press install. Host of the fore most-direct signal grounding that signal head enclosure and power supply for all-pass, external e-code reader or expansion is the best match suspension grounded equipment (i.e. signal head shell and negative electricity have ohm) to avoid grounding, noise is not easy to handle. The power issue: each host has some power lines, each with a different name and use:
(1) ACC: commonly known as "key", when key to go to the "ACC" retaining, electricity supply to the host, host, and listen to audio, you need the keys go to ACC, you can open the host. If the line received direct power supply, you can always listen to the sound, open the host does not need to use the key. Some car ACC power electricity shortage, such as the add other audio equipment, easy-to-noise. At this point the best from the battery received a line, after the relay (RELAY), and then enter the receiving host ACC, ACC power use car to start relay. (2) direct power consumption: direct-battery, at any time there is electricity, needed to supply the host computer. (3) the small lamp or instruments reset power: when the lamp is turned on, only electric supply, host led is lit. (4) starting power: when a host is open, the host-output power for use in other audio equipment, such as rising automatic antenna, starting to expand machine, and so on. Most hosts starting power is not very strong, and therefore received 2 or more expansion machine, it is best to use the relay (RELAY).
E-codes for the main function is to the fore the music signal (signal before expanding machine for ex-signal), based on the characteristics of the loudspeaker system matching, area divided into two tone road or multi-tone road; then through expanding machine push Horn 「introduction of every loudspeaker in the optimum working range work to achieve better results. The following are some proper nouns and contains codes: * HIGH-PASS: high-pass crossover points, which allow more frequency by, the following frequency filter out. * LOW-PASS: low pass frequency point, let the following frequency, the frequency filter out above. * BAND-PASS: zhongtong, highpass and lowpass, in setting the frequency range above and below are filtered out. -CROSSOVER frequency (hz): point, which means that the starting point of the damper. * FILTER SLOPE: filter slope, 12dB/OCP are generally adopted, 18dB/OCP, 24dB filtering quickest, cleanest, but not necessarily the most pleasant, as necessary to take into account the convergence of the frequency and phase. ▓ Fore expanding machine: the main function is to host the first-level signal, make better music dynamics, wider sound field, music and more pleasant. ▓ Equalizer: English name, abbreviation for EQUALIZER EQ, plus off music signals in a frequency (center frequency) expansion site, to improve the quality of the equipment. ▓ Parameter Equalizer: PARAMETRIC EQUALIZER for English, the center frequency can be adjusted with the needs of the equalizer. The Horn is the most mysterious of Hi-Fi equipment, the appearance is very close to the second branch of theHorn, the price difference may be more than 10 times, a speaker's physical characteristics (e.g. Fs, Qts, Vas, impedance curve, etc), most people can't figure out, in fact, unless you want to designed speakers or audio device, this information does not make sense, as to withstand the power, frequency response, provides only specifications use the thrust the important thing to note, there is no way that this Horn is nice. Here are some interesting things:

Impedance: most car horn is 4 ohms, 8 ohm, some car manufacturers loudspeaker ohm number very strange. Two or more speakers, after a series or parallel, impedance will change, because the host and the expansion of the machine are required in order to work more than 4 Ohms (some expansion of the function in the following 2 ohm, required at the equipment specification), must pay particular attention to the resistance problem. Through passive tap tone is composed of multiple audio channel loudspeaker system, because the capacitance, inductance or without considering the impedance. Under power: this is the average consumer to purchase the most attention in the Horn, in fact, pedestrian, stand power meaningless, a bear 80 watts of power, most likely by the Horn 25 watts of expanding machine pushing bad, a bear power 50 watt loudspeaker, you can receive 200 watts of expanding machine, makes a beautiful very loud music which does not fall. The correct use of the most important, also is to let the speaker in this part of your work, for example the treble 3.5KHz (possibly look at response frequency 6KHz) following required to filter out, 5-inch 100Hz following filtered before they are burned. Response frequency: that is the scope of the work of the trumpet, a good system, each speaker is at work within the scope of work. Efficiency: dB/W/M, which is helping a watt of power, in a meters can produce much of the sound represented by dB. The number of speakers will make up the system and to pay particular attention toefficiency problems, so as not to match. When necessary, to reduce resistance available speaker efficiency, the most common example, append to the original car horn, to make up for the treble the treble is not as elevated sound field, most of the appended the treble, the efficiency higher than the original car horn, therefore causing the treble too loud and too sharp, then in the treblePositive line-line a resistance, to reduce the treble volume. ▓ Passive tap the damper's basic line: passive tap the damper using capacitive or inductive, will expand the machine's music, a frequency above filter out (low-pass), or the following filtered (Qualcomm), and then received a loudspeaker so that each speaker at the best range. The most common with 6dB/OC and 12dB/OCT, common to the treble strings on a capacitor, 6dB/OCT-pass, conspiracy in subwoofer inductance is 6dB/OCT lowpass. The following is a basic line, note that the calculation formula of the "resistance" to the loudspeaker in the classification of frequency SIM, you must reference the impedance loudspeaker impedance curve, 4 ohm loudspeaker impedance in May when 3.5KHz to 10 Ohm. The crossover point impedance equal of line handling can also be calculated: L-inductance, generally based on mH, 1mH = 0.001H, according to the following formula in the calculated number multiplied by the number of mH 1,000. C is the capacitance, generally to MFD units (or write μ F), 1MFD = 0.000001FD, according to the following formula to calculate the number multiplied by the number of MFD 1,000,000.
L1=R÷(6.28×F) L2=0.3128×R÷F L3=0.3183×R÷F
C1=0.159÷(R×F) C2=0.0796÷(R×F) C3=0.796÷(R×F)
The so-called expanding machine, full name should be "-level power expansion machine", its main function is to provide greater strength, accurately promote Horn, produce a more pleasant music. Most hosts are expanded within a machine, it's expanded capabilities, like 800 ㏄ engine, the car can drive, expand the machine as an engine of more than3000 ㏄, providing more accurate, faster, more comfortable driving pleasure. With the aim of expanding the machine key, isn't it so that the sound of music, but to make music more pleasant. And expanding machine-related terms and meanings as follows: OUTPUT POWER: output power, this is the most important enlargement machine to WATT watt units, because the test conditions, generally indicate output power, there are two main different representation: (A) RMS POWER: under certain conditions (e.g. distortion rate 0.05%) CW output power, generally known as "WA" foot. (B) MAX POWER: maximum output power, referring to the motor nature, in an instant can output the most power, regardless of the circumstances generally known as "false false Watt". .BRIDGE: bridging, soon-to-left and right channels and a channel, and increase the output power, please note that not every single expansion machine can be bridged. .S/N RATIO: any clutter ratio to db as a unit that represents the music signal strength is greater than the noise, the larger the number the better. .THD: TOTAL HARMONIC DISTORTION THD, smaller percentage, the better. Damping FACTOR: .DAMPING, larger indicates the ability to control the Horn, the better. .GAIN: gain or input sensitivity to Volt, host of the fore output from 0.1v to 3.0v, use gain makes two match. ▓ With Basic code: expansion of the machine is an advanced audio system in the most important equipment, because the car power supply system is very special, resulting with enlargement is very susceptible to noise problems, the following is a press pack Basic code, if the application correctly, you can make the noise produced by the opportunity to reduce more than half. 1. power cable directly after the battery, do not add any of the original car fuse holder. 2. expand the machine more than two, must be from a battery pull a thicker cable, enter the Distributor block, and then expand to each machine. 3. use body grounding, bonding required end will paint scraping the dialogues as clean and shall not have the oil. (From a battery pull a negative level is not a good way. Although the effect of conductive copper is 10 times more iron, but the body of the cross-sectional area that you are using wire cross section area of ten times or times, and the battery negative terminal is not a clean earth point). 4. expand the machine more than two, the negative electrode wire required Advanced Distributor, block, and then pull a cord ground, instead of the Distributor block (also known as grounding block), and a few negative electrode wire fixed together remains the more grounded, no grounding. 5. signal cable required flash drive on large current equipment and computers, and with the power cord to a distance of at least 30 centimeters, most car steering wheel below many large electrical equipment, therefore, with the exception of a few battery in the right rear luggage compartment of vehicles, power lines go car go left, the signal cable car to the right. RCA Terminal (signal head) required plug, a lot of noise, because signal head plug crooked. 6. the signal line if necessary, and power cord right angle turn *, but never can parallel.
Noise sources and exclude methods: noise is car audio sector most headaches that occur on their causes and troubleshooting methods that you can write a book at least 200 page book, here are some of the more basic principles and methods. ▓ Generator noise: this is the most commonly encountered, the throttle is heard: Mrs.---make "sound, that is, for this type of noise, causes there are three main, as follows: grounding bad: more grounded, causing some equipment voltage reduction, the noise generated ground loop, which entered the hi-fi system. Check the power part of the method, available every meter measuring equipment with voltage of battery voltage comparison, cannot be lower than 0.1 volts; signal part, check each signal connector is loose, the main output signal head shell and power cathode is all-pass, the main ground situation is good? find out problem, exclude is very simple. Signal line induction: signal line too * near the power cord, computers or high-current components, examine the ways that you can use a different set of signal lines, go cart, connection host and expansion of the machine, such as noise disappear, move the original signal line location, you can eliminate noise; available when inevitably aluminum foil or copper network will a signal package up and grounded. Equipment not matchWhen: electronic tap tone or expanding machine gain adjustment is too large, the correct way back, you can tune out noise. ▓ Ignition noise: spark plug ignition, the engine speed faster, sound healing, problems are mostly in the high-voltage conductors isolated bad or engine shell grounding bad. Replacement conductors or enhance engine shell ground, but effectively exclude Jet engine of the car, the spark plug size wrong, it will cause problems, spark plug cannot be arbitrarily changed, the original car using "resistance spark plug" when necessary, replace the use of the same type of spark plug, and vice versa. ▓ Direction lights, Horn, noise: noise situations can easily identify the cause, as the original car that equipment failure, exclude filters, in the equipment of the power line parallel — commonly known as "the rat tail" Capacitance to exclude noise.
Fuse holder: with audio equipment required absolute compliance with a very important principle, this is the basic business ethics, "must not affect the functionality of the original vehicle and security", the sound system of power, it is best to come directly from the battery, and the name of the original car appliance product independent and combined with the appropriate fuse to protect it. A prevent burning car fuse holder: the battery, battery connection near the head and the main power supply cable, when main power line breaking the skin and short because, the fuse is broken, do not have a security problem. B protection equipment using fuse holder: when an equipment problem occurs when a short circuit, the fuse will be broken, but does not affect other equipment
Wire and the absolute sound, too thin or quality bad wire, like using too thin or obstruct pipes, cannot transfer enough water (current), cause-related equipment not fully functional. ● Wire types, depending on the use cases are divided into three categories: (a) power cord: conveying current use, particularly the expansion of the machine and the battery connection of cables. Automobile 12-volt DC power supply for the physical sizing power equal to the voltage by current (W = V * I), all power supplies will need to supply a large current, that is, the need to use thicker source line to connect, 100-Watt expand machine, at least by 12, the power cord. (12AWG smaller number, the more coarse wire diameter expressed, for example, the line than 12AWG wire 8AWG rough) (b) Horn line: connect the expansion of the machine and the loudspeaker. The more coarse wire diameter, the better, 61/2-inch and smaller Horn, use 16 or 18, the line can be. More than 8-inch subwoofer, or transmission distance of more than 10 feet, it is best to use 14, or thicker line. 　 Plating of silver or silver line (note that the silver line with tinned wire both easily confused, to strip the epidermis, silver plated wire render bright luster, tinned wire table surface is white dew, a no luster. Transfer of the to treble), has been of great help. (C) of the signal cable: transmission of signals, such as prior-stage and expansion of the host machine. Due to the fore the signal voltage low, current weak, very susceptible to electromagnetic interference, signal line numbers to braid to isolate interference. Isolated farm interference in the best way is to set the isolation level received power cathode. Isolated magnetic interference the best method is to be stranded conductor polarity. In practice, avoid the electromagnetic field intensity of the region, is the best method, if Flash is not open, to remedy available to the signal line, silver-coated material of signal delivery to treble has been of great help. ● All wire, consists of many fine copper wire strand adult, here are some of the basic principles of quality:

(A) material: oxygen-free copper (OFC OXYGEN FREE COPPER for short) materials are the minimum requirements, it is to distill the good copper, through anaerobic treatment, can withstand long make, oxidized. (B) of the same thickness and structure, the number of lines, segments, the more the better. (Iii) twisted pair copper pistil, the better it becomes more and more dense, more dense weave, the better and more uniform. (Iv) use a thicker line, no harm, too thin line will affect the sound quality, especially the bass of a lot worse for instantaneous response.