On the market, we can find
several types of Audio Compressors.
But when to use one instead of another? When using one technology, then another one?
It is renowned that with Audio Compression is easier to cause damage than make a track sound better. We also know that compression makes loud sounds quieter and quiet sounds louder.
But you don't have to slam a compressor with a basic preset on every track. We instead need to understand why we want to use a compressor.
By answering this question, we will realize which compressor to use, when and how to set it.
We can use a compressor to control and
shape dynamics by compressing a signal's peaks (or better transients) and making levels more consistent.
A transient is a short spike in volume that typically occurs at the initial attack of a sound. For example, the attack of the kick drum of a snare hits the guitar peak on a string or a vocal consonance. These are good examples of what a transient is.
So, the compressor can change the attack but also the release time of a sound. It can also be used to add punch or brighten up a sound.In fact, by modifying the initial punch of a sound and its sustain, we can also change the so-called envelope of the sound (ADSR).
A compressor can also be used to
prevent clipping during the mixing and/or mastering process or even while tracking.
In this case, the compressor is set as a limiter, like a guardian that safely controls dynamics before converting the signal to the digital domain or recording processes.
A compressor can be set as a limiter when its ratio is set to 10:1 or even higher, and the threshold is set to the maximum level the compressor can handle. This setting creates a hard limit on the signal, preventing it from going any higher than the threshold.
We can also use a compressor to add tone to a recording.
Each compressor type has its unique tone and character, like a VCA, an Optical, or a Tube Compressor.
This is why some compressors are superb on drums, vocals, bases, or room mikes, while others can add a pleasant harmonic distortion.
Depending on what you want to obtain, you will choose the right compressor for your goal, accordingly.
There are also specialized compressors like the Multiband Compressor or the De Esser and they are designed to process specific frequency ranges of sound.
Multiband compressors are used to compress specific frequency ranges independently, providing more precise control than a traditional compressor.
De-essers are used to reduce excessive sibilance (harsh high-frequency sounds such as “s” and “sh”) in vocal recordings. A De-esser is essentially a single-band compressor.
Because of its nature to make loud sound quieter and quiet sound louder, the audio compression is also used to increase the perceived loudness. For example, by compressing the room mike, we will enhance the room reverberations, making them almost as loud as the drum hit.
This characteristic creates a more even volume and makes the audio sound more cohesive as if it were all part of the same performance. Compressors also help reduce the dynamic range of audio, making mixing and matching sounds easier.
Compression can also move a recording backward or forward in the mix, giving a different proximity effect to the listener's ears. A lead vocal has to be in front of the mics, while background vocals are not.
Depending on the compressor attack and release settings, a recording can be moved forward or backward in the mix. Faster attack settings can push the recoding backward in the mix, while a longer attack can push the same recoding in front of the mix.
There are different compressor types and settings for each goal.
