As the name implies A (audio) represent audio , sound , V (video) represent audio, images, so AV amplifier is a collection of both audio and video signal processing, audio amplifier , the emphasis is the atmosphere of the sound field , specifically for home theater, its mainly by the signal source selector , signal processing, post-stage preamplifier and a power amplifier , you can switch the signal source , signal processing , and finally through the power amplifier to drive multiple speakers, generally has a front, center , surround, etc. 4-7 one channel power output , with Dolby Pro Logic surround decoder or AC-3 decoder , DSP digital sound field processing , FM / AM digital tuner radio functions, and also has a variety of audio and video input and output interfaces , as axis , optical , HDMI interface.
How to choose the AV amplifier
       AV amplifier is an audio replay of the core , its role is multi-channel sound reproduction capabilities. Comes to multi-channel surround sound playback is inseparable from the standard . In the choice of amplifier power amplifier must pay attention to whether they have now popular surround sound standard certification : 1 , Dolby Pro Logic (Dolby prologic) surround sound. 2 , Dolby Digital (Dolby Digital) surround sound. 3, DTS surround sound. 4, THX Surround EX surround sound ( 7.1 channel ) . 5, DTS-ES Discrete surround sound ( 6.1 channel ) and so on. A home AV amplifier must have at least Dolby Digital surround sound decoding playback function , because Dolby Digital is a DVD Alliance in December 1997 under the PAL system DVD mandatory audio standard , AV amplifier if the user has this feature select the basic point . Other levels of certification is a direct manifestation of the power amplifier .
Evaluation of an AV amplifier quality standards certification in addition to the obvious , there are many indicators and parameters.
1 , the output power : refers to the amplifier connected to the speakers to get the energy for power amplifier , its rated power ( power amplifier at undistorted conditions for continuous RMS output power ) is a valid indicator of performance evaluation amplifier .
2 , Distortion: The output device can not reproduce its input , generate a waveform distortion or signal component of change is called distortion power amplifier distortion is smaller, the better the sound .
3, the dynamic range: the strongest signal portion and the level difference between the weakest part of the equipment , the dynamic range of the equipment that the strength of this signal responsiveness.
4 , Damping : Damping is the load impedance of the amplifier output impedance ratio is a measure of the internal resistance of the speaker amplifier damping effect played by the size of a performance index .
5, the output impedance: The output impedance of the amplifier is its output terminals of the speaker demonstrated equivalent internal resistance , it should be consistent with nominal input impedance speaker .
6 , SNR: SNR refers to the audio signal level and the noise level in decibels between the poor. SNR higher the value, the relative noise amplifier is smaller, the better the sound quality .
7, the separation: separation means the AV amplifier surround decoder to restore the audio coded signal for each channel signals. Poor separation of the power amplifier will be panning allowed, the sound field is not full, poor audio and coherence phenomena .
Perhaps these indicators so that ordinary people are scratching their heads, that simple point, is the most intuitive drive capability ( ie, how much power ) and amplifier weight . Although the output power and the relationship between the driving force is not so direct, but has a relatively close contact, the output power is easily accessible from the specification of the indicators found , 100W, 200W, 400w even more, but sometimes need to drive capacity behind these indicators have to really listen to the real voice. It is necessary to mention the choice of speakers , and after the amp for the speaker to be driven , driving ability , the stronger the more it can control the speaker said that the power output when it is more at ease , better dig out the potential of the speaker , so the general U.S. as an AV amplifier car as they produce large displacement , high-power drive low impedance audio regarded ease. But Japan AV amplifier production was accounted for more than 80% of the market but also shows its technology is unique , so try to use high-power amp after , in exchange for a more relaxed and transient dynamic control is very important to select the AV amplifier point . Speaking of the weight of the amplifier is perhaps the most easily perceived as a power amplifier requires strong support , so the heavier the power amplifier transformer equipment index greater or use a larger capacitance , which are a guarantee of quality amplifiers and amplifier its stability as possible to avoid more severe vibrations caused unnecessary sound effects .