time constant for various displays

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This topic contains 6 replies, has 3 voices, and was last updated by Profile photo of volounteer volounteer 7 months, 2 weeks ago.

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  • #95493
    Profile photo of volounteer
    volounteer
    Participant

    What is the time constant for the various places that display signal level?

    Looking at gate, EQ, compress, on the screen ,plus channel ins , and LR out on LEDs , they show peaks at one place but not at others at that same instant in time.

    While about the same, there tends to be big discrepancies between the displayed peaks at times.
    I see red lights on the pastors mike at times but often the LR out has barely moved then.

    I suspect the time constant or sampling moment for determining peaks is the cause.
    If they are truly instantaneous then they must occur at different times.
    Else if they have an integration period that could explain the differences.
    Is there another reason?

    #95495
    Profile photo of KeithJ A&H
    KeithJ A&H
    Moderator

    @volounteer,

    I’m not sure whether you have an issue here – the only thing that stands out is your mention of ‘red lights’ on a channel without apparent peaking further down the signal path.

    We use multi-point peak detection in our digital desks. This means the Pk! LED’s will inform you of peaking (and therefore a potential issue) at different processing points in the channel (generally wherever you see a meter on the various processing screens showing the level at that point in the signal path).
    You could, for example, be overdriving the signal with the PEQ, then bringing the level back down with the compressor. Or overdriving the preamp and cutting out lots with the PEQ.
    Either way, the level to mix may look ok but the Pk! LED will be telling you that something is wrong somewhere.

    Then of course, you can investigate further.

    Cheers,
    Keith.

    #95501
    Profile photo of volounteer
    volounteer
    Participant

    @KeithJ A&H

    Thanks.

    I am not sure there is a real issue except that the lights do not seem to match up.
    I was wondering if the different displays had different ways/times of displaying results.

    I can see how compression after one might change following read outs,
    but I would still think they would be consistent.

    Sometimes the pastors mike goes red and the LR out goes up a lot.
    Sometimes his mike goes red but the LR does not move more than one green light.
    This might be because we are near the bottom of the green light range on LR which is coarse.
    (Dont ask me why – lost in history before me or our MD arrived.
    But seems to be because of the power amp being up to achieve the level needed from the old analog board)
    I already suggested they lower the power amp and up the gain in the Qu so the lights are more useful.

    The best I could see from your description is that we (actually THEY) overdrive the preamp and have heavy GEQ applied to almost the whole signal to stop feedback. The compressor will definitely get used for modestly long times during peaks.

    This might be a problem with the RF gain feeding the preamp. I only notice it on the pastors lapel mike. And then only after he has started talking a bit louder. He starts moderately low and comes up gradually, so we have the gains up as much as feasible so he can be heard at that initial time.

    I will suggest the team look at the RF level and the items you mentioned when the dealer does the install for acoustics and rerings the room and adjusts the Qu EQ with mikes and a computer program. (smaart?? did not hear them say which)

    I do not hear any damage to the signal from the red light but my ears are far from silver let alone gold these days.
    Possibly the generous headroom protected us from actual physical clipping.

    #95507
    Profile photo of Mike C
    Mike C
    Participant

    heavy GEQ applied to almost the whole signal to stop feedback

    WOW that statement right there is big red flag just how jacked up you system is!

    First of all you should be using the PEQ on the output to notch out the hot spots.

    Doing a hack job on on what I’m guessing is maybe 75% of the eq frequency bands of a GEQ more of less turns the EQ into more or an over all signal attenuator causing you to turn up the level an causing feedback yet again.
    Once again you have the wrong person coming in to “tune” system.

    As far as tuning/ringing out a system, you can only take it so far you can just keep chopping at the EQ or you will nothing left coming.

    Yes you be clipping the crap out of a channels input and not be anywhere close to clipping the actual output based on the levels and processing downstream of the channel input…. but you can’t “un-clip” that signal.

    #95508
    Profile photo of volounteer
    volounteer
    Participant

    @mikec

    That is planned in the fortnight as we redo things.

    That was not done by the wrong person coming in.
    But it was done by a person (not me) in house.

    Hopefully I have got their attention about doing things differently this time.

    The dealer coming in did some PEQ last time but when we do the acoustics and ring the room out then we will do PEQ using mikes and a pc program to get it right. At least more righter:)

    #95509
    Profile photo of Mike C
    Mike C
    Participant

    Ok I type too fast, too sloppy and the edit time ran out to clean it up a little!
    So…….

    WOW that statement right there is big red flag to just how jacked up your system is!

    First of all you should be using the PEQ on the output to notch out the hot spots.

    Doing a hack job on what I’m guessing is maybe 75% of the eq frequency bands of a GEQ more of less turns the EQ into an over all signal attenuator causing you to turn up the level and causing feedback yet again.

    Once again you have the wrong person coming in to “tune” system.

    As far as tuning/ringing out a system, you can only take it so far, you can’t just keep chopping at the EQ or you will nothing left coming out.

    Yes you can be clipping the crap out of a channels input and not be anywhere close to clipping the actual output based on the levels and processing downstream of the channel input…. but you can’t “un-clip” that signal.

    #95510
    Profile photo of volounteer
    volounteer
    Participant

    @mikec

    no edits needed
    still same answer but with some additions

    That is planned in the fortnight as we redo things.

    That was not done by the wrong person coming in.
    But it was done by a person (not me) in house; (or maybe a different dealer from the next town).

    Hopefully I have got their attention about doing things differently this time.

    The dealer coming in did some PEQ last time but when we do the acoustics and ring the room out then we will do PEQ using mikes and a pc program to get it right. At least more righter:)

    I appreciate your insights and your not being as nasty as one eye is with his replies.

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