Getting to grips with the compressor threshold setting
Simply put, a compressor’s threshold setting allows you to set the point at which the compressor starts compressing your audio signal. Any parts of your audio signal which are louder than the threshold will be turned down by the compressor. Any parts of your audio signal which are quieter than the threshold will remain uncompressed.
(Actually, that’s not 100% true. You can have the compressor apply compression to a signal before it’s crossed the threshold by softening the compressor’s knee. But when you’re first getting to grips with compression, it’s best to think of the threshold as the point below which the signal remains uncompressed, and above which compression occurs.)
Click here for a video lesson on your compressor’s threshold setting:
How should you set the compressor threshold setting?
How you set the compressor threshold is dependent on what portion of the signal you want to compress. You could set the threshold just beneath the signal’s peaks. That way you compress only the loudest parts of the signal. This can be useful in a situation where a snare drum track has a mixture of accents and ghost notes. The threshold can be set so that the compressor applies gain reduction only to the accented notes.
Alternatively, you could set the threshold to a lower level to apply compression to more of the signal. The lower you set the threshold, the greater the amount of signal you compress, resulting in greater gain reduction. This can be useful for leveling out a whole performance.
Using a compressor’s threshold setting
Depending on the design of your compressor, you will interact with the compressor’s threshold in one of two ways. The first design is a compressor that offers you a dedicated threshold control. With this, you can set the compressor’s threshold at any level you desire.
The second design is a compressor that does not offer you a threshold parameter. Rather than a threshold parameter, this design of compressor provides you with an ‘input’ or ‘input gain’ parameter. This design of compressor has its threshold fixed at a certain level. You use the input gain parameter to increase the level of the signal going into the compressor. The more you increase the input signal, the more the signal overshoots the compressor’s fixed threshold.
It’s that simple… The compressor will compress any audio signal that breaches the threshold. But the compressor will not compress anything that remains beneath it. Once you are comfortable with the idea of how the compression threshold setting works, I recommend that you move on to the compressor’s ratio setting. That’s because the ratio is the setting on a compressor that allows you to determine how much the signal is turned down once it has crossed the threshold.
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