"Auto-mute" a moment after switching phantom power

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This topic contains 17 replies, has 5 voices, and was last updated by Profile photo of GCumbee GCumbee 6 years, 6 months ago.

Viewing 15 posts - 1 through 15 (of 18 total)
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  • #40569
    Profile photo of DocDocDocDoc
    DocDocDocDoc
    Participant

    Would it be possible to silence each channel for a moment on which 48V PP status is changed? After all, the time it takes the 48V or 0V to become stable might be known. This would also work around the issue of preamp state changing loudly on scene recall. Furthermore, it would be yet another option that an analog desk couldn’t easily have.

    (This feature suggestion is a side-effect on other thoughts I posted here earlier today: http://community.allen-heath.com/forums/topic/gain-clicking-and-other-noise)

    #40572
    Profile photo of GCumbee
    GCumbee
    Participant

    While I agree that it would be nice to solve this problem I think the short term fix is to leave phantom on either all channels or ones with condenser mics and have all scenes set the same way. Then switching between scenes does not create the pops. I tried it and it seems to work. I have worked on many analog consoles with all phantom on all the time. Many consoles only have a master phantom switch snyway.

    Now purest will say not good to phantom dynamics mics. That is another argument. But if you have an aforementioned console with one switch you are doing that anyway. As for ribbons. We have all been taught not to phantom them. Most modern ribbons have transformers. I have had studio situations where we tried but occasionally one would get plugged into phantom. Never had one hurt yet. Even my precious RCA 77DX. There are arguments for miswiring or patch bay plugging that could damaged a ribbon. That is another discussion.

    #40578
    Profile photo of DocDocDocDoc
    DocDocDocDoc
    Participant

    Well, ribbons… they’re not so widely used and people using them should know what they’re doing. And the Qu-16 ist not primarily targeted for studio use anyways. You could also hook up a special mic preamp or another console via XLR and find that you just killed its outputs with 48V. Phantom power is always “think before you plug”!

    Having phantom power always on has one little issue: When unplugging mics on phantom power, all (!) channels create some noise. This noise even sneaks through to the output (perhaps via analog circuitry) when LR is muted. So while in general this might be a good idea for a single-band show, it is an issue if you have more than one act on stage and need to “re-wire” your setup in the middle. Which is a likely scenario, because this is what digital consoles with their total recall stuff actually are good at.

    #40585
    Profile photo of GCumbee
    GCumbee
    Participant

    I agree. My point was just that this same issue has been around a long time. I have been doing this since before phantom power was invented. I have seen it all. I did touring sound for many years as well as owning a commercial pro Nashville studio. It is just a matter of dealing with it. The scene change thing does create an issue but it is a workable one. We plugged and unplugged mics in studio and touring for years. We just muted the system. I still suggest turning on phantom on all scenes with condenser mics until a possible solution is found.

    #40638
    Profile photo of Nicola A&H
    Nicola A&H
    Keymaster

    V1.5 adds a 3s auto mute on Phantom Power change. Please note that this does not prevent phantom power noise when hot plugging microphones or toggling phantom power on off quickly.

    #41791
    Profile photo of MikeShand
    MikeShand
    Participant

    Any chance we could have this on the GLD? And if so would it apply on power up? The problem we have is that sometimes people shut the desk down in a hurry leaving a fader up un a channel with phantom enabled. Then when we turn it on again we get a thump as it finishes booting. We DO have a power sequencer, but unfortunately the delay is not long enough to accommodate the boot time. So the power comes on to the gld, then to the amps, THEN the gld finishes booting and… Pop.

    Obviously the solution is “don’t do that”‘ but inevitably people do!

    #41834
    Profile photo of GCumbee
    GCumbee
    Participant

    I am running into this now on a GLD 112 new install. After power up at final part of boot I get a big pop and feedback for a fee seconds then it settles down. A previous GLD install did not do this. Both have 1.4. I am trying to figure out the difference. Only thing I can solve it right now with is muting everything before shutdown and saving scene. I know that operators will forget that.

    Anyone else found a solution for this.

    #41835
    Profile photo of MikeShand
    MikeShand
    Participant

    I tried putting gates with pretty long attack times, but at the sort of times that are still viable for normal operation it doesn’t make a great deal of difference, presumably because the “signal” is so large. Strange that you didn’t have it before and now you do. I’m running 4.1. I’m looking at getting the power sequencer modified to bring the amps up after the GLD has booted, but that length of delay isn’t standard, so I’m not holding my breath.

    Sorry QU folks for hijacking your thread. Does the v1.5 fix on the QU fix the power up problem as well as the originally reported phantom status change issue on scene changes?

    #41836
    Profile photo of GCumbee
    GCumbee
    Participant

    I reinstalled 1.41 but no better. This is a bad problem. I have not seen it on previous installs but likely has to do with difference in where phantom mics are routed.

    Never had these issues on analog consoles. I don’t think the QU is doing this. Have not heard any complaints from customers.

    #41837
    Profile photo of MikeShand
    MikeShand
    Participant

    My phantom mics are all on the AR2412. Haven’t tried whether it happens on the surface inputs. I had assumed it would be the same, but you never know. Interesting you mention the feedback. I get that too, and had kind of assumed it was kicked off by the pulse of sound into the room, but I’m wondering now if the gain is actually changing as the thing comes on. Need some more experiments.

    #41838
    Profile photo of GCumbee
    GCumbee
    Participant

    I think the gain is coming up full after the phantom spike then settling down.

    I think my only hope now is saving their main scene with mains, all Auxes muted. That way on boot up this won’t happen. I am putting a DCA next to the mains on A layer then assigning it to all the Auxes on the B layer then adding it to the mutes saved so system boots up with all the outputs muted. Operator will see all those and unmute them.

    Hopefully AH can get a fix in for this on a firmware update.

    #41839
    Profile photo of MikeShand
    MikeShand
    Participant

    Hmmm. I wonder if putting the 20dB pad in and turning up the gain by 20dB would help mitigate it somewhat? Assuming there was still enough gain for the mics. I’ll give that a go next time I’m in church.

    #41840
    Profile photo of GCumbee
    GCumbee
    Participant

    I wonder how I missed this before. I guess the configurations I had did not create the same situation. Why hasn’t there been more said about it? Others have to be having this other than just us here. There has to be a way they can fire the phantom sooner so it settles before the console fully boots or have a mute all outputs till it settles. I think that is how the QU acts now. I had thought the GLD did the same…

    #41842
    Profile photo of MikeShand
    MikeShand
    Participant

    Tried the 20db pad trick this moning, and it may be a one off but it seemed better. Just a click and no feedback. I’ll see if it stays that way.

    #43420
    Profile photo of GCumbee
    GCumbee
    Participant

    This continues to be a serious problem that doesn’t seem to be getting much interest. This should not work the way it does. Seems like it could be an easy fix to change the way the phantom turns on.

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