newbie help on live dynamic compression

Discussion in 'Tracking / Mixing / Editing' started by AJinUSA, Jan 12, 2009.

  1. AJinUSA

    AJinUSA Guest

    I'm in no way, shape or form a "pro". I'm simply tasked with taking a not-for-profit/fundraiser, live play and make it sound good. So please, no flames at my obvious ignorance?

    The problem (given last year's experience) is that the various wireless mic's get shared by different actors in different scenes. Thus, from scene to scene a different person and different placement of the actual mic happens. It makes pre-leveling the incoming mics virtually impossible for anything but (maybe) the first scene.

    Thus, not as a solution, but as a crutch, I'm trying to find some dynamic compression software for the levels, in case I can't reach the mixing board's (Behringer SX2442FX) faders fast enough and therefore get horrible distortion and/or feedback to start the scene.

    I also have the U-Control202, which gives me low-latency stereo in/out to my PC - and I'm thinking of using the aux-sends to bring that out to the PC and back in to the main.

    Can someone help me figure out if there are any cost-effective (very low cost) products are appropriate? If so, does anyone have any tips/tricks/recommendations? Am I going about this the wrong way?

    Very much appreciate any ideas, links, etc.

    Thanks in advance,
  2. moonbaby

    moonbaby Mmmmmm Well-Known Member

    You aren't going to like this answer, but here goes...
    I've had to do this for church productions where there are performers wearing wireless lavs. Too many performers, too few lavs...

    What I've had to do (during rehearsals) is to notate on the script where mics are going to be changed and what the GAIN control is set at to optimize that channel for the wireless receiver. Example:
    Susan Jones hands off to Tommy Smith, set GAIN from 11:00 to 3:00.
    Using the faders to make your gain staging changes is inviting noise issues.
    Trying to use a compressor to do this for you is inviting feedback issues galore. Using a "low latency" controller doesn't really cut it in the live sound world.
    I don't suppose that the production is staged so that all of the weaker-voiced performers can use a given lav system, the stronger-voiced ones another, etc.? That would make things too easy, eh? LOL!!!!!
  3. BobRogers

    BobRogers Well-Known Member

    Got it in one! You can't do this electronically. (At least every attempt to do so that I know of has been a disaster.) Practice, record your levels, make the changes necessary in the gain/trim whatever they call it on your mixer.

    As moonbaby said, try to have people with similar vocal levels share mics if possible. Make sure that everyone is using the same mics and channels during each rehearsal and that they are putting the lavs in a similar position to what they will do when they are in costume. Get another volunteer to help (or help remind you) if necessary.

    Good luck.
  4. Codemonkey

    Codemonkey Well-Known Member

    I have a problem like this.

    The minister on Sundays wears his lav, keeps it on. All is well.

    But during his sermon he changes volume rather a lot and rather quickly too.

    How do I fix this problem?
    I'm waiting on someone realising it's a problem.

    The only way to fix this is to use a hardware compressor. Software will *not* do the job. You have a minimum latency of about 4ms using a stupid sample rate, buffer size and ultra fast PCI interface.
    Adding a plugin will make things worse *no matter how fast your PC is*.
    Unless your PC can run a compressor for X hours at a buffer size of 16 samples.
    (Tip: it can't)
  5. moonbaby

    moonbaby Mmmmmm Well-Known Member

    Yes, and I use a compressor (lightly) on my pastor's lav, too. What I believe we're dealing with is LARGE differences in vocal power between performers-amateur performers- that a compressor will not alleviate.
    Due to its' nature in trying to hammer peaks and releasing the envelope to generate make-up gain, YOU ARE VERY LIKE GOING TO CREATE MORE FEEDBACK ARTIFACTS than you thought were possible.
    RULE#1: GAIN STAGING!!!!!!!!!!!!!!!!!!! The first thing a beginner needs to learn with this gear is how gains are properly set and why. A compressor does not fix this problem. Period. Even the most expensive, sophisticated hardware out there is not designed to do what this guy needs to have done. And, as stated previously, software plug-ins are a joke in realtime live sound.
  6. Codemonkey

    Codemonkey Well-Known Member

    "software plug-ins are a joke in realtime live sound."

    Nonsense! I use them display a (pointless) FFT analysis.
  7. GxL

    GxL Guest

    May I ask what software and HW platform you use?
    And what A/D-D/A interfacing do you use?

  8. BobRogers

    BobRogers Well-Known Member

    Is it a problem? Or is it good public speaking? Maybe he wants the first line of the quite passage to move them up in their seats and make them listen more closely. Maybe he want the loud voice to make them jump. If that's the case, then just ride the fader - best compressor in the business.

    On the other hand, if he has problems with mic technique (like different volume levels when he is looking at his note vs. looking at the audience) a compressor can help after you have done as much as possible to address this with mic position. Here you want to ride the threshold of the compressor so that the knee of the compression curve separates the volume of two head positions. You want no reduction when he is looking up and a few dB when he is looking down.
  9. AJinUSA

    AJinUSA Guest

    WOW! I really, really appreciate all the responses, and I "feared" that was the case. To make it worse, I really don't have more than two or three rehersals to actually "play" with the setup, so I think the notations about who's getting what wireless is about the best I can do.

    And, yes, having all pure amateur actors, they're not going to help me do my job much. ;)

    But to BobRogers' point, I also have that issue when the actors turn their heads in different directions, etc. It's a job for a pro, but we don't have one, so I'm the guy stuck with the problem. :)

    Thanks again, everyone!
  10. Codemonkey

    Codemonkey Well-Known Member

    I use a Creative Soundblaster of unknown model number. Possibly an Audigy, actually...
    I feed it the main mix from a Phonic K-16.
    The software is Kristal and using Robin Schmidt's "SignalAnalyser" plugin. I believe is the site.

    Yes, it's good public speaking. But it's annoying for me as I turn him up when he's quiet (or he's inaudible) but when he returns to regular volume, there's instant "feedback".
    It doesn't squeal, but the 3-400Hz region becomes remarkably muddy and things get horrible. I believe the (omni) mic is picking up the speakers.
  11. GxL

    GxL Guest

    Thanks. So you don't use it for audio in and out just for audio in for metering, right? So latency is not an issue then...

    Try to cut back on the foldback levels - that is often the biggest source of feedback issues (from my experience at least). 2c :)
  12. Codemonkey

    Codemonkey Well-Known Member

    "Try to cut back on the foldback levels"
    Logical point, but there's no foldback involved. It's just a omni mic going to the 2 mains.

    I have tried to use some live effects but the (slow) machine wouldn't get better than 40ms for long.
    With a fast PC I doubt I could push 15ms.
    Fortunately hardware compressors are cheap. I've seen a Samson S-com for about £50. Stereo/dual-mono compresor...

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