STUDIO STRATEGIES
Three different flavours of bus compression
Ilpo check out mix bus compression
1 Let’s have a look at three ways to use a compressor on your mix bus. We’ll first go for a classic and gentle glue style compression. We’ll then use sidechained pumping compression, familiar from modern dance music. And finally we’ll go all in with heavy parallel compression, which can add energy and density. 2 In all of the examples, we’ll be using the fantastic Glue Compressor plugin which comes with the Standard and Suite versions of Ableton Live. If you decide to use a compressor on your mix bus, it’s important you choose a good-quality one. Not every compressor is up to this task. Try different ones, experiment freely and see what gives you the best results. 3 First we’re going for traditional SSLstyle ‘glue’ compression. The idea is to let the compressor massage the music fairly gently. This will gel all the elements of the song together, giving the mix a pleasant, breathing pulse while making it sound more solid at the same time. This is where Glue Compressor shines - the clue’s in the name! 4 The aim here is to adjust the Threshold so that the needle is moving just slightly – hovering around 0.5 to 2 dB of gain reduction. I’m going for a gentle ratio of 2:1 to keep the effect natural. I’ve set the Attack to 30ms to let the maximum amount of transients through. A Release setting of .4s seems to work well here, producing a subtle but lively ‘bounce’. 5 I don’t want to go for an obvious pumping effect here, so I’ve used the EQ section to cut some lows from the compressor’s detection circuit. This doesn’t remove lows from the music itself – it only makes the compressor react less to lowend frequencies such as the kick drum and sub bass, giving a much more even compression effect. 6 Next, it’s time to pump! We’re using the track’s kick drum to trigger the mix bus compressor. This is an effect that naturally tends to work well with genres like house and techno, but it’s worth trying with other styles of music as well. It’s sometimes more difficult to get right with broken beats, but it can sound nice once you nail it.
7 I’ve switched on the Sidechain feature in Glue Compressor and selected the Kick as the source. This makes the mix bus compressor listen and react to the kick drum alone, allowing us to make the whole mix pump in time with it. Try sidechaining to different mix elements such as the snare, bass, percussion or even vocals. 8 I’m keeping the compression Ratio at
2:1 and Attack at 30ms, but with a longer Release time of .8s this time. This gives me a more obvious and stable pumping effect. I’m not using the EQ section to cut lows from the detection circuit, because this time around I specifically want the compressor to react heavily to the kick’s low frequencies. 9 In our final example, we’re going for a heavy parallel squash. The aim with this style of bus compression is to give the mix more RMS energy and density. We’ll get away with this on the mix bus by using the Dry/Wet control on the compressor to blend a small amount of the compressed signal together with the unprocessed part of the signal. 10 To crush the signal’s dynamics, I’m going for the maximum Ratio of 10:1. I then set the Threshold so we get close to
15dB of gain reduction. A Release time of .6s works great here. Shorter release times will often make the compressor distort with high amounts of gain reduction – always listen closely for negative distortion artefacts. 11 I’m going for a shorter Attack time of
3ms here, as longer attack times will make the transients in the wet signal pop through too much with this type of heavy compression. I’m mixing the compressed signal in at 34% using the Dry/Wet control. This retains the character and transients of the original signal with an added layer of density on top. 12 As you can see, one versatile compressor plugin can be used for many different effects. To make the most out of bus compression, choose which technique you’re going to use fairly early in the process, then mix into the compressor as you’re creating your song or mix.