What are the main parameters of the compressor?

The threshold level refers to the signal level controlled by the voltage limiter. This level is really important. If it is too low, the signal will be compressed most of the time, which will distort the signal. If it is too high, it will not achieve the purpose of preventing clipping.

Second, the compression ratio

Compression ratio refers to the ratio of the decibel number of the input signal to the decibel number of the output signal after the compressor starts to compress above the threshold level, such as 2: 1, 3: 1, and the greater the compression ratio.

Then when the input signal changes, the smaller the output signal changes, the compression ratio should generally be selected from the small compression ratio, because the larger the compression ratio, the greater the distortion. Generally, you can choose 2: 1 or 3: 1, and only when the signal peak factor is large can you choose a larger compression ratio.

Third, compress the startup time.

The start-up time of the compressor refers to 63% of the time required for the compressor to enter the working state when the signal reaches the threshold level, which is generally between100 us-10 ms. If the time is too short, the program will be excessively compressed, which will affect the dynamic effect. If it is too long, it will produce a sensible initial touch and an unnatural "head aggravation" phenomenon.

Fourth, compress the recovery time.

The recovery time of compression refers to the time required for the compressor to quit the compression work when the signal exits the threshold level, which is 37% of the normal state. The recovery time is generally 0. 1s to several seconds. If the time is too short, it will produce a perceptible level change and produce a breathing effect. If the time is too long, the actual dynamic change of sound source will be destroyed.

Working principle:

The main function of the compressor is to attenuate the strong signal whose intensity exceeds a given threshold, thus reducing the dynamic norm of the signal. Expander is a weak signal whose attenuation intensity is less than a given threshold, which increases the dynamic range of the signal. Obviously, the compression and expansion here correspond to the dynamic range change of the signal, so it is sometimes called "dynamic range processor".