Band-limited sidechain vs. band-limited compression

Discussion in 'Tracking / Mixing / Editing' started by citrusburst, Feb 9, 2006.

  1. citrusburst

    citrusburst Member

    Hi there! I’ve been experimenting with the Waves Renaissance Channel plugin, and particularly the “Push the pop master” preset. It’s a pretty simple process. First, a +2db low-shelf at 250Hz and a +4dB high-shelf at ~ 3.3KHz. The EQ stage is followed by a compressor operating over the full mix, but with the side-chain bandpass filtered at 120Hz. When the preset values are tweaked a little bit, this setup yields quite a nice sound – not at all a substitute for professional mastering, but useful for quick demos. One of the particularly desirable attributes of the processing is that the compression causes the mix to kind of…congeal...really well. It breathes, if that makes any sense.

    My question is: why does this “breathing” occur? The sound is markedly different from the pumping I get when I throw a compressor with no side-chain onto a full mix. And it’s also markedly different from the sound of band-limited compression, where both the detection and the compression are only on the passband. Why does detecting over a limited band but compressing over the whole mix produce this particular kind of sound?

    Thanks in advance for your thoughts.

  2. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    It's seeing different triggers and thus will react differently.

    this isn't really used all that much in mastering, but can be extremely useful in mixing. having one track duck a little when you trigger it with something else. but in mastering you have to really be careful.
  3. citrusburst

    citrusburst Member

    Hi Michael,

    Thanks so much for the reply. Are there general guidelines for which bandpass frequencies on the side-chain yield good bus compression sounds?

    Thanks again.

  4. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    If you are doing something for radio or tv, you can feed the vocal to the sidechain of the music compressor to lower the level of the music when there's voice over. other than that, I can't think of two many uses for this in mastering.
  5. citrusburst

    citrusburst Member

    Hey Michael,

    Thanks for the reply. I'll play with that!

  6. headchem

    headchem Guest

    My favorite trick with sidechain compressors is to sidechain the bass drum to the bass guitar, so every time the bass drum hits, it ducks the bass guitar. This helps a lot with preventing bass distortion in the mastering if you're looking for a mix to be mastered really loud. Not sure if that's the kind of thing you're looking for, but that's the only connection to mastering I could think of.

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