Side-Chain misconception, help me, OK?

Discussion in 'Microphones (live or studio)' started by recarbo, Nov 12, 2004.

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  1. recarbo

    recarbo Guest

    Hey guys and gals,
    Why is a compressor's sidechain a send/return? I mean,
    I understand the signal needs to come TO the SC, but why have the ability to send FROM it? Also, does this change the signal to unbalanced at that point, and if so why would I use that signal further along in the signal chain?
  2. wayne

    wayne Guest

    The question becomes then, where does the signal going to the side chain come from? One option is to do a split from somewhere ahead and outside the compressor. Side chain out' also provides a split.
  3. come_on

    come_on Guest

    The signal does become un-balanced(mostly). This is just in case you want to use the same signal as a side-chain for another signal processor, where the intensity of the signal matters and not as much the quality.
    Hope this helped!!
  4. recarbo

    recarbo Guest

    So you guys regularly go from one processor's SC to the next!
    I never thought of that.
    I can see that the signal should come from a split (the usual way
    would be at the patch bay, right?)
    OK, I'll experiment with that.
  5. recarbo

    recarbo Guest

    "Side chain out' also provides a split."

    Let me get this straight:

    Say I'm trying to do a de-ess. My chain is mic -> pre -> compressor
    (w/SC). If SC out provides a split, can I then attach a TRS Y-cable
    into the SC, split that out, one lead going to the EQ in, the other to EQ out, and this shunts the signal correctly?

    God, I never thought of that either. Duh.

    I know I can just go try this out, and will, but, tell me anyway. :oops:

    this is such an education
  6. wayne

    wayne Guest

    The flavors I've come across are; 'side chain' or 'detector' in'; you supply the split, 'side chain' or detector' in-out on a single TRS (your TRS Y x dual TS looks good for this one) and 'in's/outs' on separate TS jacks.
  7. Randyman...

    Randyman... Well-Known Member

    Jun 1, 2003
    Houston, TX
    The sidechain is not actually part of the signal path, so even with an unbalanced "insert" style side chain with a TRS at one end and 2x TS at the other (like "inserting" the EQ in the sidechain to boost the highs - creating a de-esser) will NOT affect the balanced I/O operation of the processor.

    The same would be true if you have "balanced" sidechain jacks (a seperate send and return jack in this case). Even if you run these balanced sidechain jacks with TS unbalanced cables, the main I/O of the unit is still balanced.

    So, the sidechain is usually just an insert jack with a buffered feed of the "main input" fed to it, and then returned to the detector circuit for gain reduction (or whatever). Inserting can allow modification of the "main inputs" feed, or it could be replaced with the signal of another instrument.

    The old "send the kick drum signal to the bass guitar compressor's sidechain" is the classic example. Makes the bass guitar " duck" whenever the kick is hit.

  8. Hack

    Hack Active Member

    Mar 20, 2001
    Little Rock, AR
    I think it might help to think of the compressor as the job it is doing. For example... If you are using it to duck the bass, then the compressor is a ducker and the SC input is really a trigger input. If you are de-essing a vocal then the compressor is a de-esser, and the SC is a insert, still not in the signal path leading to the output of the compressor. However, if your ac grounding scheme is not right you can still introduce ground loops when the two units are connected.

    The point is, I have found it helpful when learning about features of gear that I dont understand, to associate them with a specific application. Duckers need input. De-essers need inserts. Say you record an upright bass with a mic that has a DI also and you were in the same room with other inst. You could use the sidechain of the compressor that is on the DI to trigger a gate on the mic.

    Or if you are Britney Spears, you use the SC of the comp that is on your vocal to control the gate on your pre recorded vocal track. True.
  9. inLoco

    inLoco Active Member

    Jul 25, 2004
    :p :lol: :twisted:

    miss britney's performance here at rock in rio lisboa was really lame... just playback... just can't understand why she isn't killed by the press and stuff like that... still remember what happened to those 2 guys... minivinilli or something...
    she should be sued by fans for that... (like those creed fans... eheheh)
  10. MrPhil

    MrPhil Guest

    But she's cuter than millivannillliiii :wink:

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