Noise gate, compressor and limiter are divided into three parts, and many Andhadhun are still confused.

Many audio debugging peers often confuse noise gate, compressor and limiter. I think all three are to control the volume, just twist the parameters casually.

But in fact, the underlying logic of the three methods in processing audio signals is completely different, and they have their own duties. Once the tune is wrong, the voice will be broken, the sound will be rigid and dull, and in serious cases, the speaker unit will be directly burned.

Noise Gate: just keep your voice down, and turn off the sound directly below the threshold.
Core function: cut off low-volume noise and release normal high-volume signals.

Simple understanding: set a volume threshold. When the input sound is lower than the threshold, the noise gate directly cuts off the signal; When the sound is greater than the threshold, the door opens and the audio signal passes normally.

Applicable scenarios:

Multi-microphone performance on stage, when the actors are not talking, cut off the environmental noise and listen to crosstalk;
The drum set picks up the sound and suppresses the cross talk between different drums and wheat.
High-frequency trampling: the threshold is adjusted too high, the small voice fragments are directly cut off, and the voice is missing at the beginning of speech; When the threshold is adjusted too low, the noise reduction effect cannot be achieved, and the environmental noise floor still exists.

Key point: The noise gate doesn't deal with loud sounds, just keep it down, and it won't turn down the shouting volume.

Compressor: Smooth out the volume gap and compress the dynamic range.
Core function: Attenuate the loud sound that exceeds the threshold, and narrow the gap between the big sound and the small sound.

When the signal exceeds the set threshold, the compressor will attenuate the volume of the excess part according to the compression ratio, and the loud sound will be suppressed and the low voice will remain unchanged. Four key parameters: threshold, compression ratio, start-up time and release time.

Applicable scenarios:

Vocal microphone: solve the problem of loud and small voice volume, and make people's voice more stable and close to the ear;
Band live, balancing the huge dynamic differences between different instruments.
Popular metaphor: the noise door is a gate. If the volume is too small, close the door and cut it off directly. The compressor is a spring. If the sound is too loud, pull it back, but it will not cut off the sound directly.

High-frequency trampling: the compression ratio is too high, the voice is lost, the breathing fluctuates, and the hearing is rigid and tired; The start and release time is set incorrectly, and the voice has obvious suction feeling, and the volume is shaking back and forth.

Important: the compressor will not cut off the sound, but will attenuate the excessive volume.

Limiter: the last insurance of the system, hard locking the peak volume.
Core function: force the top of the volume to prevent the signal from bursting.

It can be understood as an extreme version of the compressor, with a very high compression ratio. Once the signal exceeds the threshold, the volume is not allowed to continue to rush up.

Its primary positioning is the equipment protection tool, not the timbre beautification tool, which is placed at the output end of the audio processor and power amplifier to prevent the instantaneous large peak signal from breaking the sound and burning the tweeter.

High-frequency trampling: Many novices use the limiter as a compressor to do vocal processing, and the voice is directly stuck, and the hearing is stiff and harsh.

Key points: the limiter is responsible for ensuring the equipment, and don't expect to rely on the limiter to bring out good voices.

Quick comparison table of the three

Engineering standard signal link sequence
Microphone signal → noise gate (cut off noise in quiet state) → compressor (balance vocal dynamics) → EQ equalization → limiter (end level protection).

Remember one word: the noise gate is "when there is no sound"; The compressor tube is "loud and small"; Limiter tube "sound can't explode and burn equipment".

Many Andhadhun debugging rollover, mostly in reverse order, equipment abuse. Want to use compressor to eliminate environmental noise, the effect is minimal; It doesn't work at all to suppress loud voices with noise doors; If the limiter is removed, the high-pitched unit will be easily burned out in a large dynamic moment at the scene.

Tips for actual debugging
There are many gooseneck microphones in the conference room, so the noise gate should be used first, and don't rely on compression blindly;
The host and singer's voice can be compressed moderately, and excessive compression will lose the breathing sense of the voice;
Limiter is a protective tool, so don't use it for timbre modification.

Noise gate, compressor and limiter are the iron triangle of dynamic processing of professional audio system. Understanding the division of labor among the three is the real entry-level professional tuning, so as to avoid twisting the parameters just by feeling.

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