Multi-Buss Mixing Philosophy 

The question, “What’s on your mix buss?” has been all the rage for several years now. Mix engineers have been pre-mastering their work for a long time, to ensure that the mastering engineer has a clear artistic vision before manipulating the audio.

Digital audio sound quality and mixing “inside the box” (summing in the digital domain) may have caused the latest renewed interest in mix buss processors. Digital sound has often been characterized as harsh and clinical. Character pieces like a vacuum tube compressors and limiters can do a great job of warming up the sound, making it more euphonic. Insert a Manley Labs Variable Mu stereo compressor across the mix buss, and a good mix magically transforms into a juicy record.

That said, stereo mix buss processing has inherent limitations. As an example, let’s pretend that you have set the compressor’s attack and release parameters to make the song have an exciting pumping effect, in time with the music. Think EDM (electronic dance music) as an obvious point of reference. Everything sounds good… until the producer asks you to beef up the low and and add more brightness to the overall mix. All of a sudden your once warm lead vocal starts to sizzle, and the entire mix starts gasping for air every time the kick drum happens. When you are that deeply into a dense mix, adding one more straw can break the camel’s back.

The solution to this problem is actually quite simple. Instead of processing one stereo mix buss, break the mix down into several submixes consisting of components that symbiotically work together. In the video link above, I discuss the workflow of breaking the mix into three stereo buses instead of one. Buss A is for all the vocals. Buss B contains the bass and drums. Buss C includes all the harmonic instruments that are typically panned out to the sides, leaving the center of the soundstage open for maximum vocal, bass, kick and snare punch and clarity.

Each of those three busses is independently processed. They can benefit from using different attack and release settings and thresholds, as well as different EQ curves. 

Perhaps the simplest example of how to deploy this technique would be a scenario in which you want the bass & drums to have an obvious rhythmic “pump” without having the compression affecting the vocals. Further, imagine you want to brighten all the harmonic instruments a lot, without adding sibilance to the vocals. No problem with submix processing!

(Video courtesy of Dangerous Music, Inc.)

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4 thoughts on “Multi-Buss Mixing Philosophy 

  1. Alex Ponce says:

    Hola amigo.
    What do you with all the FXs?
    You send then with their instrument (example Snare rvb to the drums buss and all vocal Fx to the vocals buss)??

    What if you are using the same reverb or dly for some drums, some guitars and some vocals?

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    1. Yes, Alex, that is correct. I route the vocal FX to the “all vocals” submix and the drums FX to the drum submix. If multiple sources are going to the same effect, I route the return to whichever submix makes it sound best. For example, if I have mostly lead vocal being bussed to a reverb along with just a little bit of snare drum, I will place the return in the vocal stem. On the other hand, if there’s a lot of snare and only a little bit of vocal, I will put the return in the drum stem. Each of the stems use different compression characteristics, so the amount of effect that you hear will be determined by the compressor. That’s why you have to put some thought into which submix takes the return. Make sense?

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  2. djdowntown says:

    Hi Michael , great post – do you have any favorite compressors you like to use on the a,b,c buses? And do you typically insert it pre or post eq? Cheers

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    1. Thanks, Darren. Any good compressor that you like should be able to get the job done. That said, I’m currently using a pair of Tonelux TXC compressors on the bass+drums buss, and Avalon AD2044s on the vocals buss and the “side instruments” buss. I follow the comps with Dangerous Bax EQs on the instrumental busses and Avalon AD2055 on the vocals buss.

      On the final mix buss before printing the mix, I mix & match Dangerous Compressor, Tonelux TXC and Manley Variable-Mu. No EQ on the mix buss.

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