Join Brian Lee White for an in-depth discussion in this video Understanding threshold, part of Foundations of Audio: Compression and Dynamic Processing.
- View Offline
Compressors, like all dynamics processors, work by measuring the incoming signal's amplitude against a user- defined reaction point, where the compressor will begin to work. This reaction point is known as the compressor's threshold. Think back to our example of watching TV and turning down the volume at a commercial break. We all have a unique threshold of how loud is too loud and what will force us to grab the remote and turn down the volume. That volume level is our threshold, and is actually the most important component of any dynamic processor.
In a compressor, a signal level above the threshold will cause the compressor to react, while a signal level below the threshold is left unaffected. The threshold's value is generally measured in the dBFS to match our DAW's metering; therefore, a value of 0 dBFS means that threshold is sitting at the digital clipping point and can go no higher. The Threshold level goes down as you dial it deeper into the negative numbers. For example, a threshold setting of -20 dBFS would cause the compressor to react to any signal whose amplitude is measured at over -20 dBFS up through 0 dBFS.
Therefore, a signal of -10 dBFS could trigger a reaction in the compressor, while a signal of -25 dBFS would not. Now that we know what threshold is and how to read its values, how do we actually use it? Well, that depends on a number of other compression parameters, including ratio, which we will discuss in the next movie.
- Measuring amplitude
- Understanding dynamic range
- Introducing compressors
- Utilizing compression ratios
- Applying attack and release
- Evening out a vocal performance with compression
- Adding punch and sustain to drums
- Using compression presets intelligently
- How to record with compression
- Solving common mix problems with limiters
- De-essing a vocal track
- Using gates and expanders
- Controlling frequency content with multiband compressors
- Using sidechains creatively
- Keying gates and compressors
- Fixing overcompressed tracks
- Using mixbus compression
- Working with parallel compression
- Compression and limiting best practices