Some little knowledge about theater power amplifier

                                   Some little knowledge about theater power amplifier

The power amplifier is referred to as the power amplifier, commonly known as the "amplifier", which is the most basic equipment in the audio system. Its task is to amplify the weak electrical signal from the signal source (in the professional audio system, it is from the mixer) to drive the speaker to make sound . The function of the power amplifier is to amplify the weak signal from the audio source or the pre-amplifier to push the speaker to play. A good set of sound system power amplifiers is indispensable.

At present, high-definition has become a popular element, and high-definition TV, high-definition movies, high-definition cameras, high-definition video cameras, etc. have been integrated into our daily life without knowing it. The power amplifier, as an important part of the home theater, of course has to be upgraded to high-definition.

AV amplifier

AV power amplifier, as the name implies, A means audio and sound, and V means audio and images. Therefore, AV power amplifier is an audio-visual amplifier that integrates audio and video signal processing. It is mainly used to cooperate with image sources to produce audio-visual integration. Create a sound field as the main design purpose, specially for home theater use.

It uses its internal delay and reverberation processing circuits to control the delay time between each channel during playback, and simulates the sound field in various listening environments by adjusting the length of the delay time. The technical indicators of high-fidelity Hi-Fi power amplifiers mainly include output power, harmonic distortion, signal-to-noise ratio, frequency range, rated impedance and damping coefficient, etc., especially emphasizing harmonic distortion and signal-to-noise ratio; while AV power amplifiers also have these Technical indicators, but more emphasis on channel isolation, delay time range, various sound field modes and other index parameters.

decoding format

At the heart of a home theater system is the surround sound system. With a surround sound system, the effect in the theater can be achieved in the home. Surround sound system is a multi-channel playback system, there are many formats, and different formats have different characteristics. Moreover, the number of various channels of power amplifiers is increasing, not only 5.1, 6.1, but also 7.1, 8.2 and so on.

power matching

The focus of the AV power amplifier is to create an ideal listening environment with visual effects, creating a realistic sense of orientation, presence and shock. Therefore, the design focus of the AV power amplifier is more on the clarity of the dialogue and the large dynamic "burst" effect of the audio-visual environment, restoring or simulating the sound field positioning of the integration of sound and picture, and creating various sound field atmospheres. In this way, not only the frequency range of the AV power amplifier is required to be as wide as possible, the degree of distortion is small, the signal-to-noise ratio is high, the transient characteristics are good, the sound quality and timbre are beautiful and pleasant, etc., but more attention is paid to the sound pressure level: that is, under the premise of low distortion, to ensure Large enough output power.

interface

The signal transmission of traditional home theater is nothing more than through optical fiber, coaxial and RCA analog interfaces. For example, the previous DTS and Dolby’s various codes all transmit digital compression codes to AV amplifiers through optical fiber and coaxial interfaces. decoding. As the latest generation of digital interface, HDMI has been widely used in various digital products, and with the application of HDMI interface in audio-visual products and the maturity of technology, more and more power amplifiers have also begun to use this theoretically lossless power amplifier. the transmission method.

channel separation

Separation refers to the ability of the surround sound decoder in the AV power amplifier to restore the audio coded signal to each channel signal, and also indicates the degree of mutual "isolation" of the signals between each channel of the amplifier. The value is expressed in decibels, the larger the dB value, the greater the isolation between them, the smaller the mutual "crosstalk" of the sound between each channel restored by the amplifier, and the better the sound effect. When choosing an AV power amplifier, the larger the difference, the better, generally more than 60dB.

Signal to Noise Ratio

The signal-to-noise ratio is referred to as the signal-to-noise ratio or the signal-to-noise ratio, and the unit is dB, which refers to the ratio of the useful signal output by the power amplifier to the useless noise. The current signal-to-noise ratio index of the power amplifier can fully cope with general music programs, so we should pay more attention to the background signal-to-noise ratio. You can try to turn the volume of the power amplifier to the maximum and listen to the noise. Of course, the smaller the better. .

Latency range

Anyone who has built a home theater knows that when the surround sound speakers are placed in place, it is generally necessary to adjust the surround delay of the AV power amplifier, so that the sound effects of the front and rear speakers are integrated and perfectly integrated, and a satisfactory overall effect is obtained. This delay time range refers to the adjustable speaker "delay" allowing the processor to automatically compensate for room size.

Frequency response

The frequency response indicates the consistency and sensitivity of the amplification of each signal of different frequencies when the amplifies signals of different frequencies, also called "frequency range". The wider its range, the better it can "take care" of signals with more frequency components, the better the performance, and it has practical value.

The power amplifier can be said to be the largest family of all kinds of audio equipment. Its main function is to amplify the weaker signal input by the audio source equipment, and generate a large enough current to drive the speaker to reproduce the sound. Due to the consideration of power, impedance, distortion, dynamics, and different use ranges and control adjustment functions, different power amplifiers are also different in internal signal processing, circuit design and production technology.