1. Power Band Width: The frequency response range is 20Hz to 80KHz, and the frequency response of the speaker from bass to treble requires a response range of 20Hz to 20KHz. As the "bottleneck" component of signal transmission, the power amplifier requires a wider frequency response, such as 7Hz to 80KHz, in order to ensure the integrity of the signal.
2, Signal to Noise Ratio (Signal To Noise Ratio): This is a parameter that directly reflects the quality of the power amplifier, generally above the 80dB ratio, high quality products often reach more than 105dB, if you pursue sound quality purity, then this value It cannot be ignored.
3, distortion (THD): This can be combined with the power amplifier's other two important indicators "Rated Power" (Rms) and "High Power" (Peak Power). When a power amplifier is operated under its Rms power, the distortion should be relatively small, generally ranging from 0.5% to 0.01%. When the Peak power or bridge is connected, the signal may be distorted, clipped (incomplete signal), and the distortion ratio will increase. About 0.5% to 1% is normal. The smaller the distortion ratio, the better the sound effect, which is also an important indicator for measuring a power amplifier.
4. Input Sensitivity: This is the calibration level set for different manufacturers, different brands of host and preamp source, ranging from 100mv to 4V or higher. It must be matched with the audio source when tuning.
5, Input Impedance (Input Impedance): Generally require the amplifier input impedance to be high, the output impedance to be low, the higher the input impedance, can more effectively block all kinds of noise, the common value is 10KΩ or higher.
6. Load Impedance: The household power amplifier is generally 8Ω/4Ω; the vehicle power is 2Ω to 8Ω in stereo; the bridge is 4Ω to 8Ω. However, some specially designed amplifiers have impedances as low as 0.1 Ω and are capable. At this time, a power amplifier can connect dozens of woofers together to create an ideal sound pressure level (sound pressure refers to the pressure generated by the sound on the human ear, which is a measure of the sound system's ability, because the higher the sound pressure is The higher the system requirements, the higher the domestic record is 141.5dB and the foreign country is 176.5dB). Just like the dozens of woofers in the car, the van can smash the glass, but this situation, I am afraid to see it in the audio game.
7. Damping Factor: This coefficient is calculated from the rated load (4Ω) output impedance. It is generally believed that the smaller the output impedance is, the higher the damping coefficient is, the better the amplifier is. In fact, high-quality power amplifiers, the ratio is mostly above 50, and some even exceed 500. Although some experts believe that the damping coefficient of 50 or so is enough, but in my personal experience, the coefficient is high, the wire requirements can be relaxed. In contrast, too high a coefficient will affect the tone, but it will help the bass performance.
8, working voltage: car audio generally works within the range of 10V ~ 15 V.
9. Slew Rate: The high-amplifier stage of the power amplifier per unit time will amplify the strong signal excitation into high-voltage, high-current AC audio. The high-end model is 30V/us or more, and the individual is over 50V/us. The ratio is high, the conversion ability is good, the level and dynamics of the music can be restored to the original sound when the speaker is combined.
Amplifier and speaker
The combination of power amplifier and speaker is mainly power matching and style matching.
Power matching: If you are the first to play the sound, but also want to DIY yourself and do not want to fake the hands of others, I recommend the same Rms power. First, it is not easy to smash the horn, and it is not easy to burn the coil (the power is insufficient, and the horn coil is easily burned). If it is a master and the economy is generous, it is worthwhile to use a high-power amplifier to drive the speakers and pursue meticulous sound.
Style matching: Japan, the United States equipment, consciously compensate for low frequency, high frequency, the sound is often less than the European product balance. The tastes are different, and the princes themselves taste.
Installation on the car
Many introductions must have made everyone aware of the importance of amplifiers to the entire sound system. Since the power is placed in the audio, it is very important to ensure the normal operation of the amplifier.
First install the power amplifier in the car, in addition to the matching with the speaker, the supply of electricity, including wire considerations, reasonable wiring, should be noted in advance. When installing, all kinds of wire should avoid short circuit, good insulation installation, such as adding density board (this is a special wooden board, commonly used for speaker production, also known as wooden raft board), to avoid directly nailing on the body iron, and make noise.
The current car audio installation process, especially the Hi-end level design, often pays great attention to the installation process, and the system layout of the tailgate is beautiful. The charm of the amplifier is artistically displayed through exquisite craftsmanship. This is not only a pleasing pleasure, but the technical requirements are very strict.