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Sam Spoons
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Loc: Manchester UK
Re: Stopping feedback from the monitors - how??? new [Re: Ronnie Wibbley]
      #1020937 - 26/11/12 07:14 PM
Arondite, first go and read this thread from the beginning. You'll probably find this site usefull too http://www.astralsound.com/basics.htm he speaks a lot of sense.

In the live music world 'monitor' and 'foldback' are used to describe the same thing, but 'monitor' also means studio control room speakers which may be leading to confusion (your 'monitor' send may be a separately controlled mix output intended for studio monitors which is no use for foldback). If your desk is like most you should be sending to your monitor/foldback speakers from a pre-fade 'aux' send.

Let us know what your system is, desk, mics, FOH amps/speakers and foldback (monitor) amps/speakers. I assume you are not milking drums, guitar amps etc but tell us what backline is in use.

Finally (for now)..... 40 x 15 year olds playing and singing metal together, that sounds like an impossible task for a sound engineer


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zenguitarModerator
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Re: Stopping feedback from the monitors - how??? new [Re: Sam Spoons]
      #1020944 - 26/11/12 08:23 PM
Quote Sam Spoons:


Finally (for now)..... 40 x 15 year olds playing and singing metal together, that sounds like an impossible task for a sound engineer




Up there with 15 x 40 year olds jamming blues at an open mic night

Andy

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Sam Spoons
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Re: Stopping feedback from the monitors - how??? new [Re: zenguitar]
      #1020947 - 26/11/12 08:35 PM
Yup


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Guy Johnson



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Re: Stopping feedback from the monitors - how??? [Re: Ronnie Wibbley]
      #1021031 - 27/11/12 11:44 AM
EEK!!!!

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Zan Man



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Re: Stopping feedback from the monitors - how??? new [Re: Ronnie Wibbley]
      #1021923 - 02/12/12 06:47 PM
Do you get a chance to soundcheck, or is it - as most pub bands - walk in, dump stuff into relative positions, plug in and play? Is it definately "monitor induced" feedback? Have you tried turning the front of house off, and have the band play with just their backline and what they would hear in their monitors? I have had the "low end howl" as you stated in the original post on more than one occasion and when the F.O.H. is muted it has dissapered. A quick play with a F.O.H. graphic can solve this, sometimes room acoustics will induce a howl from mics via F.O.H. then to monitors. What is the singer(s) mic technique? Can they get closer to the mic? This should give you more "juice", so you can back the gain off.
Also if its just vocals in the monitors, press in the low pass filter on the channel strip (I believe someone has already mentioned this). If still persistant, mute each channel at a time until you find the culprit. Hopefully you can EQ it out.

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IvanSC



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Re: Stopping feedback from the monitors - how??? new [Re: Ronnie Wibbley]
      #1024143 - 13/12/12 04:56 PM
Is it just me, or have we all become a trifle spoilt?

Monitors of any sort in the average pub gig would have been unheard of back in the day.

Never had them at the Hope and Anchor, etc.

And since they are apparently causing feedback, dare I suggest that w are all plying too loud for the room?


nah - thought not....

Level is never a substitute for powerful playing (NOT loud playing, to labour the point here)

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Sam Spoons
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Re: Stopping feedback from the monitors - how??? new [Re: Ronnie Wibbley]
      #1024197 - 13/12/12 10:32 PM
+1, it's about the music, we did manage without foldback once upon a time and coped fine, maybe we didn't sound as polished as we do now but it was (and is) live music and the performance Is what counts. The tech should support the art not the other way around.

OTOH, with both my SE and guitarist hats on when the tech works it's brill


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byacey



Joined: 08/03/13
Posts: 5
Re: Stopping feedback from the monitors - how??? new [Re: IvanSC]
      #1047055 - 08/05/13 03:52 AM
Quote IvanSC:



No - sounds to me like you are working with really inexperienced people with little or no stagecraft, but who imagine they are going to get the equivalent of their home hifi right in their ears onstage.



Many amateur musicians think they have to be playing flat-out to be effective. The truth be known, if they could arrive at a good sounding mix playing acoustically on the stage without any sound reinforcement, they would be way ahead of the game. Experienced musicians can do this, and it makes life easy for the sound man - throw the faders up and let them go; the band mixes themselves. Big bands do this all the time, and the individual musicians listen to how they relate volume-wise to the others around them. In the old days, all that was needed was a single microphone for the vocalist, and it also picked up and reinforced the acoustic stage mix just fine.

Unfortunately it's more common for everyone to be fighting for the top of the volume heap because they don't know their place and function in the mix.

Edited by byacey (08/05/13 03:53 AM)


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Mike Stranks
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Re: Stopping feedback from the monitors - how??? new [Re: byacey]
      #1047084 - 08/05/13 09:41 AM
Quote byacey:

Quote IvanSC:



No - sounds to me like you are working with really inexperienced people with little or no stagecraft, but who imagine they are going to get the equivalent of their home hifi right in their ears onstage.



Many amateur musicians think they have to be playing flat-out to be effective. The truth be known, if they could arrive at a good sounding mix playing acoustically on the stage without any sound reinforcement, they would be way ahead of the game. Experienced musicians can do this, and it makes life easy for the sound man - throw the faders up and let them go; the band mixes themselves. Big bands do this all the time, and the individual musicians listen to how they relate volume-wise to the others around them. In the old days, all that was needed was a single microphone for the vocalist, and it also picked up and reinforced the acoustic stage mix just fine.

Unfortunately it's more common for everyone to be fighting for the top of the volume heap because they don't know their place and function in the mix.



As someone whose clientele are a high percentage of amateurs I think it's somewhat more nuanced than just the issue of "playing flat-out". Although that is often the problem it can also be an unfamilarity of playing on a band/group and lack of confidence in their own abilities.

One of the key differences that I notice when working with very experienced musos is the relative speed with which the monitor mixes are created. A quick, no-nonsense, "I want this, this and this and nothing else", followed by a few initial tweaks and then a final adjustment when the the full band/group is playing ensemble - that's job done.

Contrast that with the less-experienced who will agonise and fret over the monitor mix, constantly wanting to revist it and almost invariably get into louder and louder and louder unless I tactfully try and restore some order. The big problem is that because they've got used to working this way it ends up as the ONLY way they feel they can work.


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Hugh RobjohnsAdministrator
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Re: Stopping feedback from the monitors - how??? new [Re: Arondite]
      #1047096 - 08/05/13 10:57 AM
Quote Arondite:

My condenser mic is about 50cm away from my monitor, with the mic tilted upwards and the head facing away from the monitors.




Why only 50cm? You'll certainly get the system to how-round more easily if the mic is close to the monitor wedges, but it's not very practical. Probably easier and more representative if the mics are where they would normally be for the vocalists etc... unless you're expecting to work with very short vocalists!

Quote:

I use my computer's DAW Presonus Studio One to record the feeding sound, then run it through a Spectrum analyzer, also in the DAW, to locate the frequencies that are ringing.




This kind of technique is okay as a learning aid but, again, not very practical in the grand scheme of things. It is worthwhile training your ear to recognise different pitches of how-round instinctively, rather than relying entirely on an off-line process which takes far too long in the heat of a real gig. It takes a while, but it is a skill well worth mastering.

Quote:

I then tune down the frequencies, but the mic still seems to feed at about the same gain and fader settings as before.




Then you're not doing what you think you're doing, or you're using the wrong tools!

Are you sending the mic output to just one monitor or all of them at the same time?

What kind of equaliser are you using to turn down the first howl-round frequency?

Where is it connected in the signal path?

Most people would use a 31-band graphic on the aux output feeding the monitor -- but are you using one EQ for all the monitors, or does each monitor (or group of monitors) have it's own?

In general, as you use the appropriate filter band on the graphic to reduce the system gain at out the first howl-round frequency, you should then find you can increase the mic gain slightly until a second how-round starts, normally at a different frequency. You can then use the relevant filter band to reduce that problem frequency and increase the gain again until a third starts... The amount of attenuation at each how-round frequency should be sufficient to control it, but no more, and be aware that adjacent filter bands will interact to some extent. Usually, after dealing with the dominant first three howl-round frequencies you will then have a pretty stable system with 6-10dB more gain than was initially available before howl-rounds, and hopefully it wont sound too coloured.

H

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Hugh RobjohnsAdministrator
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Re: Stopping feedback from the monitors - how??? new [Re: Arondite]
      #1047098 - 08/05/13 11:08 AM
Quote Arondite:

With regards to the music involved, it is metal, with 40 15 year old's singing/playing instruments, with a drum at the back. Since I can only spare 3 condensers and a couple of dynamic mics for the show, the condensers are placed further away from the singers than usual to capture the sound more uniformly. Thus, the likelyhood of a feedback is high (I get about 3-4 feeds on good days).




Do you really need monitors when there are 40 kids on stage all hitting things? And even if you do, (so they can hear a backing track, perhaps), do you really need to feed them with the outputs of what are, essentially, ambient mics?

The likelihood of feedback is directly depending on the overall gain from mic, through the monitors, through the air and back into the mic again. You need to minimise that 'loop gain' which you can do by: 1. minimising the mic gain (perhaps by moving mics closer to the source), 2. minimising the monitor level (turn down the monitor amps and/or move the monitos closer to the people that need them!, or 3. minimising the amount of sound getting from the monitors to the mics by careful positioning of both and choice of polar patterns of both.

Quote:

As for the 50 cm thing, it is the distance between the monitor and the condenser, when I am trying to ring out the frequencies (not the actual placements).




The important thing is how the system howls-round when the mics and monitors are in their working positions, with their working gains... not some artificially contrived arrangement that bears no relationship to the working conditions!

Quote:

My mixer has a port called "monitor output", and my monitors are plugged through it.




This could well be your major 'oops' moment. In most cases, the 'monitor outputs' of a desk are designed for control-room monitor speakers, not stage foldback wedges! Understanding the signal path of your mixer is fundamental to using it effectively... But we've covered that ground several times before, haven't we?

In most cases, stage foldback monitor wedges should be driven from the desk's pre-fader aux sends, and the front-of-house PA speakers from the desk's main stereo mix output. In a PA application, the desk's monitor section main outputs wouldn't be used, and instead the monitor section would simply be used to select sources to check on headphones -- eg, channel PFLs etc.

H

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Mike Stranks
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Re: Stopping feedback from the monitors - how??? new [Re: Ronnie Wibbley]
      #1047180 - 08/05/13 03:30 PM
Hugh: as always your advice is on the money and will be useful to all who read it.

But I just wanted to observe that Arondite's last post in the thread was almost 6 months ago; from this and other threads it appears that he's now left the building.


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Hugh RobjohnsAdministrator
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Re: Stopping feedback from the monitors - how??? new [Re: Mike Stranks]
      #1047185 - 08/05/13 03:43 PM
Quote Mike Stranks:

But I just wanted to observe that Arondite's last post in the thread was almost 6 months ago; from this and other threads it appears that he's now left the building.




Good spot! Perhaps he's graduated from school now...

Hugh

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OneEng



Joined: 28/04/13
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Re: Stopping feedback from the monitors - how??? new [Re: Ronnie Wibbley]
      #1047196 - 08/05/13 06:01 PM
Start by moving to IEM's ..... and super-gluing them to the guitar players ears so he can't take them out.

Once everyone can hear the monitor mix, then you can start getting them to turn down their instruments to get the stage volume lower and get rid of the mush coming out of the FOH from all the stage noise getting picked up by the vocal mics.

Furman makes a fairly in-expensive IEM system that uses CAT5 cable. Two people can share a single receiver and you need a single send unit. This will give you multiple mixes that the band members can control. Sell off the wedges and the amps to pay for the Furman system.


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Mike Stranks
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Re: Stopping feedback from the monitors - how??? new [Re: OneEng]
      #1047197 - 08/05/13 06:31 PM
Quote OneEng:

Start by moving to IEM's ..... and super-gluing them to the guitar players ears so he can't take them out.

Once everyone can hear the monitor mix, then you can start getting them to turn down their instruments to get the stage volume lower and get rid of the mush coming out of the FOH from all the stage noise getting picked up by the vocal mics.

Furman makes a fairly in-expensive IEM system that uses CAT5 cable. Two people can share a single receiver and you need a single send unit. This will give you multiple mixes that the band members can control. Sell off the wedges and the amps to pay for the Furman system.



In theory, yes...

... but some people either take a very long time to get used to IEMs or never do...

And if you're a jobbing sound-man (like me) working with all sorts of different people and groups and varying levels of expertise and experience you can't simple give them an IEM pack and say "That's your monitors". Well you could, but if they've never used them before then the gig would probably be very rough indeed and they wouldn't work with you again!

At the shallow-end where I mostly work, IEMs are a totally alien concept and are viewed as only used by 'names'. And very few amateur bands would contemplate paying for their own system - decent ones cost. They 'hire' me - using the word in it's loosest sense - to provide the complete solution - often assuming that even the mains extension cables needed for their set-up will be available.


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