Ringing Out The Room – Channel or Overall PEQ?

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This topic contains 170 replies, has 21 voices, and was last updated by Profile photo of zzzzzzris zzzzzzris 5 years, 6 months ago.

Viewing 15 posts - 106 through 120 (of 171 total)
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  • #47623
    Profile photo of [XAP]Bob
    [XAP]Bob
    Participant

    An Internet forum getting off topic – that would never happen 😉

    #47641
    Profile photo of coffee_king
    coffee_king
    Participant

    So, I’m still toying with this an I have my tops set up on speaker stands in my small dinning room.

    I start making the system feedback while trying to adjust on the PEQ.
    Each time I try for as tight a notch as possible and drop it -3db to start with

    These are the frequencies I encountered in order.

    4667
    328
    398
    5188 – So here I’m out of PEQ adjustments already
    328 (Back again so I reduced DB to -4.3)

    At this point the system sometimes rings out one, sometimes another different one.
    I can hear two or three at once as well.

    3158
    3161
    2982
    3700

    and onwards and onwards and onwards.

    I try making a fatter notch to try and catch two or more with one PEQ, but I’m still running out of PEQs.

    I assume I’m reaching maximum gain before feedback?

    I stop trying to make it feedback and listen how the mic channel sounds.
    It has a lot of bottom end resonance when I talk through the microphone. This is never appearing when I try to make the system feedback, but I manage to get rid of it by PEQing its channel.

    If anyone has any further thoughts it would be much appreciated.
    Please bare in mind that I’m still learning here.

    #47642
    Profile photo of Andreas
    Andreas
    Moderator

    Setup PA in dining room? Guess its rather easy to get feedback at any frequency you want, just by moving the mic a little.

    How large is your room to accomplish setting up the mic behind the PA?

    I assume I’m reaching maximum gain before feedback?

    yes.

    And -3db is nothing to handle resonances but something cosmetic to the sound. If you have a real room resonance (the ones you observe below 400Hz), try to notch out at least -6dB or even further (thats why you want a rather high-q/steep notch filter).

    A resonance accumulates same sound coming back in phase at one spot (your mic). Assuming a single reflective wall you’ll see an amplification of +6dB at the resonant frequency. To counteract that one with some EQ you have to drop by at least -6dB. If sound accumulates from multiple sources, more reduction may be necessary.

    #47699
    Profile photo of coffee_king
    coffee_king
    Participant

    Im setting up for a gig right now. Its in a social club with a decent proper stage in a good sized room with nice and high ceilings.

    A)Ive given up trying to make the room feedback as I just seem to keep going and going. Each time I get rid o a frequency another occurs.
    Any advise?
    B) There are two vocal mics on stage. The singer is talking/singing through it. If I mute one a lot of the ringing disappears, but then the second I add in a second mic ringing occurs. Same the other way round.
    Any advise?

    #47701
    Profile photo of GCumbee
    GCumbee
    Participant

    I think it keeps coming back to what we have suggested. Feedback is going to happen. You have to accept that. What you do to minimize it is the thing. You should only try to ring a few freqs as we have said. When you get to the point that you hear multiple freqs it’s time to quit. You have got to change mics, move the speakers or just lower overall gain. If the vocals are still not loud enough then the band has to back off. It is all common sense and physics. If you want to hear the vocals the band has to player lower. Plain and simple. Or put NO band through the speakers. I do shows all the time and have for over 40 years. I have never had the issues you seem to have. I don’t know what else we can do to help.

    #47703
    Profile photo of Andreas
    Andreas
    Moderator

    I do shows all the time and have for over 40 years. I have never had the issues you seem to have.

    Same for me (ok, only three decades), and we didn’t had IEMs but bad wedges and selfmade PA stuff within the early years.

    Maybe its simply an operational issue between your singers and their mics. Maybe they’re singing way to far away from the mics or are just not singing loud enough. Turning down the vocal sends to the IEMs may help (this is your control to get the vocalists sing louder).

    #47704
    Profile photo of dpdan
    dpdan
    Participant

    replace your dynamic mics with AKG C535EB mics,
    yes, the AKG 535 mics can feed back too, but the difference in useability and sound quality is outrageously beneficial.

    let’s say this again,,,,
    when “ringing out” only dip three different “offending” frequencies,,, then quit. NO MORE!

    Quite possibly the very best results will be experienced when you get rid of the idea that every job has to be “rung out”

    An equalizer is a tool, but you never use it unless you know exactly how to “fix’ the problem of bad tone quality or excessive feedback. A carpenter never uses every tool in the workshop just because it’s there. If you do not know the pitch of problematic frequencies when you hear them, you will almost never gain any kind of improvement by just twideling and sweeping around.

    Get yourself at least one AKG C535EB mic and try it.
    You will NOT be dissapointed, you will discover just how much difference there is compared to the dynamic mics, especially SM57 and SM58 mics. The tone quality and volume consistency of the vocalist moving around the 535 is massively consistent compared to any dynamic microphone.

    #47705
    Profile photo of Dick Rees
    Dick Rees
    Participant

    CK…

    It’s difficult if not impossible to do Internet sound triage without a whole host of pertinent information Sometimes the needed info is not presented because the poster is unaware of a particular issue or somehow believes that it doesn’t matter. Not saying that you’re doing this, just observing a general trend which makes things difficult. That said…

    It appears to me that you’re trying to use EQ to solve a problem which is not amenable to using EQ as a solution. No matter what we tell you and what you try, you’re apparently having the same problem over and over. This in itself should tell you that perhaps you should be looking somewhere other than EQ. A medical analogy would be complaining that a bandage just won’t stop the bleeding no matter how it is applied when the proper solution is to sew up the gaping wound with stitches. IOW, work as far “upstream” as possible.

    Here’s a quick check list:

    1. Check your mains speakers for any variations in response, either some “hot bumps” or some response dips. You can do a cursory evaluation using pink noise and the built in RTA. Do your testing outdoors in free space. Set your test mic half way between the speakers and as far out from them as they are apart.

    2. Disengage all compression, EQ, gating, reverb…ANYTHING processing or affecting the signal. Do this before running any testing or evaluation.

    3. Check your microphones to make sure that their patterns are as they should be. Mics can “go omni”. In your case, I’d be very suspicious of the off-brand mic the other vocalist is using until it is proven to have a solid polar pattern and reasonable frequency response, lo to hi. You can check the mics by playing any sound source, then listening to the mic in your headphones and rotating it through 360 degrees to evaluate the polar pattern by ear. Listen in particular for the null spot(s) where the maximum rejection of the sound source is located.

    4. No matter how it offends your aesthetic sense, get your mains off the stage. Get them up at least 7′ to the bottom of the cabinet if you can and aim both speakers at the mid-point of the rear wall. This is just a general rule. Some exceptions may apply in oddly shaped or very deep rooms. When using the “boost to identify” method with the mic in the middle of the room, do not attempt to deal with anything over 350hz. Neither should you set more than 4 PEQ filters. You’re dealing SOLELY with room resonances/standing waves…nothing more…no “feedback”…NOTHING.

    5. When mixing, use dynamic processing only for a specific reason, not just because it’s available or someone else does it for some unknown reason. Until you can set up your system properly from step one, NEVER put compression on the mains bus. NEVER.
    You’ll hear people talk about using mains bus compression to “glue the mix together”. This is studio stuff in the main and has no place for someone trying to simply set up their system for maximum response and stability.

    Again: find the wound, stitch it up and stop trying to apply EQ “band-aids”. That’s not the way this works.

    Sincerely offered with best wishes.

    DR

    #47706
    Profile photo of coffee_king
    coffee_king
    Participant

    Hi all
    Ok. So maybe I’m going to far here with is possible.
    So when tuning the the room which feedbacks am I supposed to rid of? The first three I come to?
    Moving on from this I maybe getting the word feedback mixed up with another word (Possibly resonance)?
    For instance:
    Vocals mics on, drummers drums mics are on. Drummer hits kick drum pedal. Resonance frequecies come through the vocal mics.
    Just to check I mute the vocal mics and theres no resonance frequencies to be heard?
    Advise on that issue?

    #47707
    Profile photo of GCumbee
    GCumbee
    Participant

    Open mics are going to pickup a certain amount of room ambience or drums no matter what you do unless you want to tightly gate the mics which won’t give natural results. If it is low resonance try engaging you high pass filters on the vocal mics and start around 80-90 and go up till the resonance boominess lessens but doesn’t make the mic sound too thin. Try that.

    #47708
    Profile photo of Dick Rees
    Dick Rees
    Participant

    Hi all
    Ok. So maybe I’m going to far here with is possible.
    So when tuning the the room which feedbacks am I supposed to rid of? The first three I come to?
    Moving on from this I maybe getting the word feedback mixed up with another word (Possibly resonance)?
    For instance:
    Vocals mics on, drummers drums mics are on. Drummer hits kick drum pedal. Resonance frequecies come through the vocal mics.
    Just to check I mute the vocal mics and theres no resonance frequencies to be heard?
    Advise on that issue?

    What part of “you can’t fix it with EQ” do you not understand???

    You need to start at the beginning and deploy your system so it doesn’t feed back. EQ has nothing to do with this other than addressing 3or4 room resonances below 300hz.

    Everything else depends on knowing how to set up your speakers in the right place and to choose mics that give you the best chance to max out your system gain.

    EQ HAS NOTHING TO DO WITH IT (caps for emphasis, not yelling).

    George…

    I think the “gate the mic” thing has been debunked earlier in the thread and actually causing some of his problems (“mics feed back upon drummers first hits”). He has no optical gates…

    #47709
    Profile photo of Dick Rees
    Dick Rees
    Participant

    For instance:
    Vocals mics on, drummers drums mics are on. Drummer hits kick drum pedal. Resonance frequecies come through the vocal mics.
    Just to check I mute the vocal mics and theres no resonance frequencies to be heard?
    Advise on that issue?

    You very likely have a combination of too high a setting on the mic input gain coupled with poor drum tuning and/or a very resonant, hollow stage. Most of this can be alleviated by using the HPF on the vocal mics.

    There’s also a chance that it is the sum total of ALL the mics on stage interacting, not just the vox mics. Deducting two…any two…may well give you the same result depending on the exact circumstances.

    #47710
    Profile photo of GCumbee
    GCumbee
    Participant

    Dick. My point was not my choice but an extreme example.

    #47774
    Profile photo of coffee_king
    coffee_king
    Participant

    I once again thank everyone for their responses.
    I have included some images from the evening so you can see what the set up was like.

    As you say, maybe I have too much gain on my mics?
    But I was always shown/read to have as much gain as possible on mics with the clip light only just occasionally flashing?

    Again I stress that I think I’m getting confused with the words “Feedback” and “Resonance”/Ringing” somewhat.

    I’m not singing into a microphone and its screaming feedback back at me, more when I stop singing (Sometimes when Im still up against the mic, sometimes I can be standing somewhere else on stage) feedback will eventually start to slowly come in, or a ringing/resonance sound will occur and then disappear after I stop singing, so kind of like a “Hello…..rrrrrring”. Its there, then its gone.

    I swopped the two vocal mics (AKG D5 and Sontronics STC-80) for 2xSM58 mics and things did improve a bit with the AFTER ringing/resonance disappearing somewhat.
    But again maybe this is due to the fact that SM58s have a much lower volume than my other two mics.

    As suggested I will try to lower the gain on the mics next time.
    Also as suggested I will use more of the high pass filter on the vocal mics to try to eleviate this resonance boomness after noise.

    Note: On Saturday I turned down/off ALL effects as there was enough reverb in the room.

    If you do not know the pitch of problematic frequencies when you hear them, you will almost never gain any kind of improvement by just twideling and sweeping around.

    I have been finding the pitch using an app called FFT Plot

    suspicious of the off-brand mic the other vocalist is using

    Sontronics? Off brand? Hardly.

    4. No matter how it offends your aesthetic sense, get your mains off the stage. Get them up at least 7′ to the bottom of the cabinet if you can and aim both speakers at the mid-point of the rear wall.

    I always do have my mains “Off stage”. It is interesting what you say about speaker height though. I have gone from about this 7′ rule to lower (just about ear/top of head hight) recently to try to get more volume to guests ears. But I will try this 7’ next time.

    Once again, I thank you all for your tips.

    http://thiscarbonfootprint.co.uk/qu-16/Cons-Club-May-2015-2.jpg

    http://thiscarbonfootprint.co.uk/qu-16/Cons-Club-May-2015-1.jpg

    #47778
    Profile photo of Andreas
    Andreas
    Moderator

    With the pictures in front I’m even more irritated. If you observe feedback above 1kHz I’d really check the pattern of the PA or overall volume. Not sure how loud you expect your music has to be, but comparing room dimensions with PA size I can imagine you’ll have to run your PA rather high to get some serious amount of volume in the back of the room.
    For this type of conventional speakers you’ll obtain highest air pressure around the PA (= near the stage). If the mids are not directional (into the audience only) I start to understand your problem…

    Regarding the Mic Gain: Its not the gain of the mic channels its the overall gain from microphone up to the speakers. Reducing Mic Gain and raising master volume to obtain same loudness changes nothing regarding feedback.

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