Sidechain Compression for Film

Hi everyone, in my last post I talked about how space can be made in the mix for simultaneous lines of dialogue by subtle panning. Here I want to talk briefly about another technique that you can use to reach a similar result. Often times in action movies, there will be lots of sound effects occurring at the same time as a character is speaking, such as explosions or gunfire. To ensure that the desired tracks remain the focal point of the mix, you can apply sidechain compression to duck the less desirable sounds.

A lot of EDM producers use this technique for their music to compress the melodies of their songs using the kick drum sound as the key input, but it can be used in a number of contexts, including this example on a rock track that has been explained by Graham from TheRecordingRevolution.


This could be used in a number of ways in a film context depending on the desired effect. While audio in real life would dictate that the sound of gunfire should overpower the dialogue, this isn’t necessarily the case with creative projects where the dialogue is often the more important sound to be purveyed to the viewer. In this case, you could send your effects to an auxiliary track that has a compressor on an insert, then use the dialogue as the key input, either by way of using the audio track directly, or in the case of multiple lines of dialogue, another auxiliary track that your dialogue has been routed to.

While this technique definitely has it’s applications in film, I did not think it was necessary to implement it in my Starship Troopers sound replacement. This is because I wanted the scene to be kind of chaotic and the panning automation on my lasers in combination with the spread of static panning from my machine guns made enough room in the mix for my dialogue as it was. If I had a lot of effects that were in the centre of my mix, or that overlapped the location of my dialogue then it would be a lot more appropriate to use this technique.