015 – parallel processing

Last week we went over some bass programming and processing techniques, and I mentioned parallel processing. I also mentioned it in some of the posts on eqs and filters, so this week we’ll dive further into parallel processing and what you can do with it.

While it may sound super fancy and complicated, parallel processing is something you are probably already doing. It is balancing a processed signal with an unprocessed signal, to get a mix of the effect which isn’t overpowering or destructive. The Dry/Wet control on most effects does this very easily, although there are other ways of going about creating a parallel chain. You can use Ableton’s effect racks to create an entire effects chain – not just a single effect instance – and mix it with a dry chain to add slight distortion, colour, or reverb to your sound. I do this very often with the GlitchMachines plugins mentioned in an earlier post, sometimes stacking 2-4 chains of glitchy mangled silliness with a dry chain playing just slightly louder.

Parallel compression may be what comes to mind first when talking about parallel processing. I think the easiest way to learn this is to duplicate whichever track you would like to parallel compress, and putting an aggressive compressor on one channel. You can use a preset for this, or program your own. I usually go for -8 to -12dB of gain reduction (make sure to turn off makeup gain and match levels yourself). On its own, this will almost always sound absolutely terrible, but now – while playing both the uncompressed and compressed channels – you’ll turn the compressed channel level way down, I would suggest to the point where you can’t hear it, and bring it back up until it starts to add some weight and volume to the mix. I would suggest starting with this duplicated track method until you are confident with the process, and then move to either a parallel effects rack or simply the dry/wet knob which is present on most compressors, again being careful to level-match so you can properly judge the efficacy of the parallel compression.

Parallel compression can be really valuable for adding weight to basses and kicks, punch to mid-range elements, and overall to add volume or (with the right compressor model) a little colour as well. Be careful on bass elements, as it’s very easy to kill the low-end entirely with phase cancellation. I use this technique on my high-hats buss in many mixes, with just a little bit of AudioDamage’s RoughRider2 compressor mixed in. I like that particular compressor for this because it softens some of the harshness which can come from extremely high-frequency sounds, and it can soften the transients just a touch without killing the punch or dynamics. This one is easy to overdo, but as anything, when used right it’s perfect.

You can also set up an equalizer or filter in parallel effects chains, to boost or cut some of the audio signal, or to add a resonance peak without disrupting too much of the sound. This can also add some phasing artifacts, but above the bass range, it isn’t always super detrimental. Use your ears, and you should be able to tell what is good and bad. In the mid to high-frequency range, some phasing issues are often perceived as stereo width, which can really open up your mixes and bring elements out of a track.

You can also experiment with sidechaining or gating the affected signal, to add some depth to the sound design and create space for both the dry sound and the effect channel. This can have a similar effect as chokes within a drum rack, or something like a trance gate, depending on the audio elements and effects used. I will sometimes gate a signal so just the peak comes through, and then use a delay or reverb on the peak; adding that touch of space to the mix without the mud and fuzziness which can also occur.

I may come back to parallel chains in a later post, but that covers the basics for now. I haven’t decided what the next few posts will cover yet, but tune back in next Monday for more production tips.

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