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Title: Problem removing frequency in monitor
Post by: Greg Bartusch on December 12, 2012, 01:07:31 AM
Last weekend I was mixing a band in a bar. The stage is small 15'W x 8'deep. Ceiling is low 7' tall.
I use 4 monitor mixes from FOH on a A&H Mix Wizard. I have 4 EQ's for each monitor. (Center mix uses 2 monitors) Monitors are Yamaha MSR 400's. Mains are PRX series (if that's needed).
Just a heads up since the stage is so small I have to pull out almost all the frequencies out for the monitors or they will feedback. I've never found a solution for this. (Maybe a feedback eliminator)?
The lead singer the other night would talk in his beta 58 and I would get a 250Hz that I could not remove from the monitors because all the frequencies on the monitor EQ's are totally pulled out. Why would I still get 250Hz coming through the monitors when he talked or sang? Really the only way to remove this is to turn down his monitor channel. Then he can't hear himself.
Should I put the monitors on milk crates to bring them closer to the singer? Should I get better monitor EQ's.?The current ones are dual 15 band (forgot the brand)but not great ones. I haven't had this issue with other singers in the past, just this one guy. Was it just his voice? I want to fix this because the same band will be back in the future. If I left anything out, let me know. Thank you for any info.
Title: Re: Problem removing frequency in monitor
Post by: Nathan Salt on December 12, 2012, 02:38:44 AM
What do you mean by all the frequencies are pulled out? As in all the faders on the graphic are turned down? Because all that does is turn the whole level down and completely mess with the phase of the signal and give you way more problems.
Title: Re: Problem removing frequency in monitor
Post by: Dave Bigelow on December 12, 2012, 02:41:36 AM
If you're pulling out that many frequencies then you're doing something wrong.

Flatten out the EQ, turn the sends down a bit and start over.
Title: Re: Problem removing frequency in monitor
Post by: Mark McFarlane on December 12, 2012, 04:45:59 AM
If you're pulling out that many frequencies then you're doing something wrong.

Flatten out the EQ, turn the sends down a bit and start over.

+1

Also, minimizing feedback with a 15 band EQ is like nailing tacks with a sledge hammer.  You might drive the tack but you're gonna damage everything around it.
Title: Re: Problem removing frequency in monitor
Post by: Douglas R. Allen on December 12, 2012, 05:48:34 AM
If you're pulling out that many frequencies then you're doing something wrong.

Flatten out the EQ, turn the sends down a bit and start over.

+1

Also, minimizing feedback with a 15 band EQ is like nailing tacks with a sledge hammer.  You might drive the tack but you're gonna damage everything around it.
*****************************************
These two above. Also any chance there was something wrong with his microphone? Swap that out next time as well and see it the problem gets better. Of course check the monitors themselves.  Blown horns?

I'm guessing you have a Bata 58A and the lead singer is center stage. This mic has a supercardioid pick up pattern. If your using the 2 monitors on one mix for the lead singer make sure they are placed around 40 degrees Left and right of the singer. Down load this link
http://www.shure.com/uploads/specification_sheet/upload/123/us_pro_beta58_specsheet.pdf.pdf
and look at the polar plots. Imagine your singer being at the
 -20 db area. Place your monitors in front of the singer around the 120 to 150 degree area. Keep the microphone Level, not pointed down at the monitors as well.
Last if this a very small stage sometimes its worth trying side fills. Have 2 speakers on tripods L/R and maybe just 1 floor monitor properly placed in the center. Gives better overall sound without that 250 hz on the floor mud that you may be hearing.
Douglas R. Allen
Title: Re: Problem removing frequency in monitor
Post by: Ivan Beaver on December 12, 2012, 07:20:40 AM
In this case-more IS NOT better.

As others have said, you are doing it wrong and not understanding the purpose of the eq.

Once you have "rung out" a couple of "hot spots' you need to STOP!  It is not going to get any better-or louder.

Only start to sound worse.
Title: Re: Problem removing frequency in monitor
Post by: Nicolas Poisson on December 12, 2012, 07:49:34 AM
Maybe the folks on stage are too loud. It is always a good thing to have low level on stage, and this is even more true as the stage is small. Appart from feedback problems, it also helps having a good sound in the FOH (less bleeding). I know this is hard to explain musicians to play at a lower level (there is the groove you know, etc.). Not beeing able to hear oneself is a relative question of monitor too low or stage sound too hot. Technically, lowering the second parameter is more efficient.

My stage is only 8'x10', and I never had any problem of feedback with any voice mic, including SM58, Beta58, Beta87, SM86, Audix OM3, Beta57, KMS105... I even never had to play with the EQ to eliminate feedback on voice mics. However:
- the FOH is made of coaxial speakers, and there is at least 3 feet between the "FoH plane" and any microphones
- monitors are good coax as well
- I have 31 bands + parametric on every outputs (digital board)
- I put 4 inches rigid rockwhool on stage left and rear wall

I have more problems miking the upright piano with Beta98. I cannot raise the volume as loud as I would like sometimes, because this starts feeding back with the FoH (no monitors - do not even think about it);

So, a few tips :
- lower stage volume if possible
- good placement of monitors with respect to microphones, taking directivity into account
- maybe less instruments in the monitors
- check the remainging feedbacks are not due to the FoH
- then, if it does not help, maybe you'll have to invest.
Title: Re: Problem removing frequency in monitor
Post by: g'bye, Dick Rees on December 12, 2012, 08:54:37 AM
Last weekend I was mixing a band in a bar. The stage is small 15'W x 8'deep. Ceiling is low 7' tall.
I use 4 monitor mixes from FOH on a A&H Mix Wizard. I have 4 EQ's for each monitor. (Center mix uses 2 monitors) Monitors are Yamaha MSR 400's. Mains are PRX series (if that's needed).
Just a heads up since the stage is so small I have to pull out almost all the frequencies out for the monitors or they will feedback. I've never found a solution for this. (Maybe a feedback eliminator)?
The lead singer the other night would talk in his beta 58 and I would get a 250Hz that I could not remove from the monitors because all the frequencies on the monitor EQ's are totally pulled out. Why would I still get 250Hz coming through the monitors when he talked or sang? Really the only way to remove this is to turn down his monitor channel. Then he can't hear himself.
Should I put the monitors on milk crates to bring them closer to the singer? Should I get better monitor EQ's.?The current ones are dual 15 band (forgot the brand)but not great ones. I haven't had this issue with other singers in the past, just this one guy. Was it just his voice? I want to fix this because the same band will be back in the future. If I left anything out, let me know. Thank you for any info.

Greg...

If you cut all the frequencies on the EQ (or any EQ), you have in effect created a "flat line" across the entire frequency range with no boosts or cuts, just "X"dB lower in level. When you apply make-up gain somewhere (anywhere) you're back to square one with a "flat" EQ.

See?

Si.
Title: Re: Problem removing frequency in monitor
Post by: John Halliburton on December 12, 2012, 09:13:03 AM
Last weekend I was mixing a band in a bar. The stage is small 15'W x 8'deep. Ceiling is low 7' tall.
I use 4 monitor mixes from FOH on a A&H Mix Wizard. I have 4 EQ's for each monitor. (Center mix uses 2 monitors) Monitors are Yamaha MSR 400's. Mains are PRX series (if that's needed).
Just a heads up since the stage is so small I have to pull out almost all the frequencies out for the monitors or they will feedback. I've never found a solution for this. (Maybe a feedback eliminator)?
The lead singer the other night would talk in his beta 58 and I would get a 250Hz that I could not remove from the monitors because all the frequencies on the monitor EQ's are totally pulled out. Why would I still get 250Hz coming through the monitors when he talked or sang? Really the only way to remove this is to turn down his monitor channel. Then he can't hear himself.
Should I put the monitors on milk crates to bring them closer to the singer? Should I get better monitor EQ's.?The current ones are dual 15 band (forgot the brand)but not great ones. I haven't had this issue with other singers in the past, just this one guy. Was it just his voice? I want to fix this because the same band will be back in the future. If I left anything out, let me know. Thank you for any info.

Along with the other suggestions, I'll add this-since it is a small stage, also check to make sure the feedback isn't in the house speakers.  Do you have eq's on the house sends?

As others have said, and it bears repeating, slamming all the faders down on an eq does more harm than good.  Look through the "Study Hall" here and read Chuck McGregor's paper on gain structure through the sound system and how to set it up correctly.

Best regards,

John
Title: Re: Problem removing frequency in monitor
Post by: Mark McFarlane on December 12, 2012, 10:31:16 AM
...

Once you have "rung out" a couple of "hot spots' you need to STOP!  It is not going to get any better-or louder.

Only start to sound worse.

+1. The max number of bands I'll cut on a 31 band EQ is 4-6.  That means after you pull down 2 or 3 faders on your 15 band EQ then STOP.  Any more adjustments and you are trashing the sound and causing other problems.

I'd put a 31 band EQ on my wish list for Santa Claus.
Title: Re: Problem removing frequency in monitor
Post by: John Roberts {JR} on December 12, 2012, 11:04:40 AM
Back when I was pimping FLS I spent many hours demoing 1/3rd octave EQ while managing feedback. When you have a system well rung out, turning up the gain higher will cause a growling sound as all three or four dominant modes start trying to break out simultaneously (corrective EQ makes them all have the same likelihood to feedback).

Do a search for past discussions explaining why there are only a handful of specific feedback modes. Short answer= it's the gain "at" a those frequency modes as defined by path length- transit time/wavelength.

JR
Title: Re: Problem removing frequency in monitor
Post by: Roland Clarke on December 12, 2012, 11:28:58 AM
Back when I was pimping FLS I spent many hours demoing 1/3rd octave EQ while managing feedback. When you have a system well rung out, turning up the gain higher will cause a growling sound as all three or four dominant modes start trying to break out simultaneously (corrective EQ makes them all have the same likelihood to feedback).

Do a search for past discussions explaining why there are only a handful of specific feedback modes. Short answer= it's the gain "at" a those frequency modes as defined by path length- transit time/wavelength.

JR

Well I'm not going to repeat what has already been said here, however, I wouls suggest you look at the amount of gain and stage volume, also, in situations like this, you might be better off running the monitors as side fills rather than stuck on the floor.  If you have a couple of pole mount stands (assuming that the monitors are also equiped with the hat sockets) it can be a good way to get clarity and monitor level without feedback.  Just a suggestion.
Title: Re: Problem removing frequency in monitor
Post by: Robert Weston on December 12, 2012, 12:50:39 PM
Last weekend I was mixing a band in a bar. The stage is small 15'W x 8'deep. Ceiling is low 7' tall.
I use 4 monitor mixes from FOH on a A&H Mix Wizard. I have 4 EQ's for each monitor. (Center mix uses 2 monitors) Monitors are Yamaha MSR 400's. Mains are PRX series (if that's needed).
Just a heads up since the stage is so small I have to pull out almost all the frequencies out for the monitors or they will feedback. I've never found a solution for this. (Maybe a feedback eliminator)?
The lead singer the other night would talk in his beta 58 and I would get a 250Hz that I could not remove from the monitors because all the frequencies on the monitor EQ's are totally pulled out. Why would I still get 250Hz coming through the monitors when he talked or sang? Really the only way to remove this is to turn down his monitor channel. Then he can't hear himself.
Should I put the monitors on milk crates to bring them closer to the singer? Should I get better monitor EQ's.?The current ones are dual 15 band (forgot the brand)but not great ones. I haven't had this issue with other singers in the past, just this one guy. Was it just his voice? I want to fix this because the same band will be back in the future. If I left anything out, let me know. Thank you for any info.

Try trimming down the mic gain on the singer (and possibly any other open mic you have).  The mic may be too hot.  All things being relative, with lower mic gain, you can usually get a louder stage.
Title: Re: Problem removing frequency in monitor
Post by: Mac Kerr on December 12, 2012, 12:51:49 PM
Try trimming down the mic gain on the singer (and possibly any other open mic you have).  The mic may be too hot.  All things being relative, with lower mic gain, you can usually get a louder stage.

Please explain what you mean or how this works.

Mac
Title: Re: Problem removing frequency in monitor
Post by: Robert Weston on December 12, 2012, 01:04:39 PM
Please explain what you mean or how this works.

Mac

If the mic is too hot, it will be overly sensitive to sound.  So, reduce the input gain on the mic channel.  When the gain is lowered, the monitor speakers (for his monitor) can be turned up so he can hear himself.

Ringing out the monitors for his channel would still be needed.  But adding the process lowering his mic gain should be considered part of (or at least as a candidate) for a solution.

Title: Re: Problem removing frequency in monitor
Post by: g'bye, Dick Rees on December 12, 2012, 01:18:33 PM
If the mic is too hot, it will be overly sensitive to sound.  So, reduce the input gain on the mic channel.  When the gain is lowered, the monitor speakers (for his monitor) can be turned up so he can hear himself.

Ringing out the monitors for his channel would still be needed.  But adding the process lowering his mic gain should be considered part of (or at least as a candidate) for a solution.

Robert....

When I first came on the PSW forums, I made the same assertion.  That was several years ago and the bruises have healed.


No matter how "hot" you have the mic, the laws of physics declare that "the loudest sound at the mic wins".  The actual fact is that a strong singer working a tight pattern mic very close combined with the monitor properly positioned "in the null" will allow you to run the input gain lower.

You're looking at it backwards.







 
Title: Re: Problem removing frequency in monitor
Post by: Patrick Tracy on December 12, 2012, 01:18:47 PM
If the mic is too hot, it will be overly sensitive to sound.  So, reduce the input gain on the mic channel.  When the gain is lowered, the monitor speakers (for his monitor) can be turned up so he can hear himself.

Ringing out the monitors for his channel would still be needed.  But adding the process lowering his mic gain should be considered part of (or at least as a candidate) for a solution.

Nope. Gain is gain; 3dB down at the pre and 3dB up at the amp yields no change in the overall gain or the susceptibility to feedback. The only way that can make a difference is if there's some other factor like distortion or dynamics processing in the chain.

Title: Re: Problem removing frequency in monitor
Post by: Samuel Rees on December 12, 2012, 01:43:33 PM
When I first came on the PSW forums, I made the same assertion.  That was several years ago and the bruises have healed.

I had the same misconception, corrected not long after I started coming around here. Seems to be a soundman-myth that sticks around.
Title: Re: Problem removing frequency in monitor
Post by: Tim McCulloch on December 12, 2012, 02:09:55 PM
If the mic is too hot, it will be overly sensitive to sound.  So, reduce the input gain on the mic channel.  When the gain is lowered, the monitor speakers (for his monitor) can be turned up so he can hear himself.

Ringing out the monitors for his channel would still be needed.  But adding the process lowering his mic gain should be considered part of (or at least as a candidate) for a solution.

Explain how lowering the level at one end of the equation and raising it an equal amount at the other end results in a lower level.
Title: Re: Problem removing frequency in monitor
Post by: Robert Weston on December 12, 2012, 02:13:54 PM
I agree with what everyone has said.  And yes, 3db down on one item and 3db up on another is no change. 

Dick - your explanation of a tight mic pattern is dead on.  I'm lucky to work with bands who perform like this... rarely any mic issues.

The "hot" input gain I'm referencing is from past experience working with other bands whom turn the input pots full clockwise to get "the best sound out of the mic".  And they always had problems with feedback across many frequencies.  When I started working with the bands, I trimmed every mic'd input down to manageable levels and notched where I could - this fixed their feedback issues and they were able to keep their monitor speakers (wattage) where they liked it (loud).

The point I'm making is, I don't know how hot the OP runs the inputs, but from his explanation of the issues (especially with a Beta58), it sounded very similar to my past experiences... which was resolved by first trimming all the mic'd inputs.
Title: Problem removing frequency in monitor
Post by: Samuel Rees on December 12, 2012, 02:36:22 PM
I agree with what everyone has said.  And yes, 3db down on one item and 3db up on another is no change. 

Dick - your explanation of a tight mic pattern is dead on.  I'm lucky to work with bands who perform like this... rarely any mic issues.

The "hot" input gain I'm referencing is from past experience working with other bands whom turn the input pots full clockwise to get "the best sound out of the mic".  And they always had problems with feedback across many frequencies.  When I started working with the bands, I trimmed every mic'd input down to manageable levels and notched where I could - this fixed their feedback issues and they were able to keep their monitor speakers (wattage) where they liked it (loud).

The point I'm making is, I don't know how hot the OP runs the inputs, but from his explanation of the issues (especially with a Beta58), it sounded very similar to my past experiences... which was resolved by first trimming all the mic'd inputs.

I still don't think that makes sense. If a preamp is set to 40 db of gain ('too hot'-ish for a 58), and you reduce that to 25 db of gain, then turn your fader up 15 db, everything is exactly the same. If I understand you correctly, the only way what you are saying makes any sense is if whatever combination of fader position and preamp gain you configured resulted in a net reduction of volume from the previous configuration... which is of course, the same as turning it down via any means.

I think what you are saying is that it is possible to have the same output volume, but a different vulnerability to feedback, depending on how you configure your preamp gain and fader. This is not how it works though!
Title: Re: Problem removing frequency in monitor
Post by: Jordan Wolf on December 12, 2012, 03:28:17 PM
The "hot" input gain I'm referencing is from past experience working with other bands whom turn the input pots full clockwise to get "the best sound out of the mic"…

The point I'm making is, I don't know how hot the OP runs the inputs, but from his explanation of the issues (especially with a Beta58), it sounded very similar to my past experiences... which was resolved by first trimming all the mic'd inputs.
It seems that some of the bands you've worked with might have enjoyed that analog distortion that slamming a mic pre and impart to the signal.  That could account for certain frequencies (harmonics) standing out, thus causing a higher chance of feedback.

What seemed to fix the issue, however, was proper gain structure management.
Title: Re: Problem removing frequency in monitor
Post by: Robert Weston on December 12, 2012, 03:45:56 PM
I still don't think that makes sense. If a preamp is set to 40 db of gain ('too hot'-ish for a 58), and you reduce that to 25 db of gain, then turn your fader up 15 db, everything is exactly the same. If I understand you correctly, the only way what you are saying makes any sense is if whatever combination of fader position and preamp gain you configured resulted in a net reduction of volume from the previous configuration... which is of course, the same as turning it down via any means.

I think what you are saying is that it is possible to have the same output volume, but a different vulnerability to feedback, depending on how you configure your preamp gain and fader. This is not how it works though!

I think we are talking about the same concept.

Using your example, the 25db gain on the Beta (established from the trim) would be the "starting point" (not the 40db - hopefully no one would start it that hot) with the slider or aux-send turned all the way down... with the channel PFL showing (i.e) +3db with a vocal input.  Then more db is added to the signal as it's passed through the aux-send or fader.  Maybe another way of saying it, the 25db level at the input is (do I dare say) less sensitive than 40db. 

It just sounds like the OP may have an input level too hot for the offending freq. if they are unable to notch it out.  At lease rule out a "hot" input.



 
Title: Re: Problem removing frequency in monitor
Post by: Robert Weston on December 12, 2012, 03:47:06 PM
It seems that some of the bands you've worked with might have enjoyed that analog distortion that slamming a mic pre and impart to the signal.  That could account for certain frequencies (harmonics) standing out, thus causing a higher chance of feedback.

What seemed to fix the issue, however, was proper gain structure management.

Exactly.
Title: Re: Problem removing frequency in monitor
Post by: g'bye, Dick Rees on December 12, 2012, 03:50:31 PM
I think we are talking about the same concept.

Using your example, the 25db gain on the Beta (established from the trim) would be the "starting point" (not the 40db - hopefully no one would start it that hot) with the slider or aux-send turned all the way down... with the channel PFL showing (i.e) +3db with a vocal input.  Then more db is added to the signal as it's passed through the aux-send or fader.  Maybe another way of saying it, the 25db level at the input is (do I dare say) less sensitive than 40db. 

It just sounds like the OP may have an input level too hot for the offending freq. if they are unable to notch it out.  At lease rule out a "hot" input.

My money is on the fact that the OP has really cheap, unsuitable EQ's and doesn't know how to use them.  Combine that with clueless musicians onstage carrying bags and bags of bad habits they justify with "we've always done it this way" or "dude, it's my SOUND" and you can see the problem.......

Forget about the "hot input" scenario.  It has long ago been debunked.  Think OE....
Title: Re: Problem removing frequency in monitor
Post by: Bob Leonard on December 12, 2012, 05:52:41 PM
And why so many monitors and mixes for a stage that size. Why is it that newbs always have to mic everything, have way too many monitors and can't manage stage volume in a 50 square foot room. Once again sport fans, it's all bullshit for stages and rooms that size.
Title: Re: Problem removing frequency in monitor
Post by: Mac Kerr on December 12, 2012, 05:53:22 PM
If the mic is too hot, it will be overly sensitive to sound.  So, reduce the input gain on the mic channel.  When the gain is lowered, the monitor speakers (for his monitor) can be turned up so he can hear himself.

No. As was pointed out in a thread about guitar feedback, gain is gain. It does not matter whether it comes at the mic pre control, or the amp control, the feedback will occur at the same amount of total gain.

If the mic gain is too hot you may get clipping on the input of the console, but it does not make it "overly sensitive to sound".

Mac
Title: Re: Problem removing frequency in monitor
Post by: Bob Leonard on December 12, 2012, 06:04:23 PM
There is no way to change the sensitivity of the microphones element. What you can change is the channel gain which is the input level control for the channel strip. The mic will be no more or less able to pick up sound regardless of the channel strip gain control setting. Additionally the mic pattern will have an effect on the mics ability to reject side noise, back noise, or stage wash. With mics and monitors less is always more.
Title: Re: Problem removing frequency in monitor
Post by: Robert Weston on December 12, 2012, 08:30:56 PM
My money is on the fact that the OP has really cheap, unsuitable EQ's and doesn't know how to use them.  Combine that with clueless musicians onstage carrying bags and bags of bad habits they justify with "we've always done it this way" or "dude, it's my SOUND" and you can see the problem.......

Forget about the "hot input" scenario.  It has long ago been debunked.  Think OE....

Excellent!  And this seems to be normal for many bands.


No. As was pointed out in a thread about guitar feedback, gain is gain. It does not matter whether it comes at the mic pre control, or the amp control, the feedback will occur at the same amount of total gain.

If the mic gain is too hot you may get clipping on the input of the console, but it does not make it "overly sensitive to sound".

Mac

Correct.  I hesitated with the use of the word "sensitivity"; and yes, gain is gain.


And why so many monitors and mixes for a stage that size. Why is it that newbs always have to mic everything, have way too many monitors and can't manage stage volume in a 50 square foot room. Once again sport fans, it's all bullshit for stages and rooms that size.

hmmm... perhaps I can use your phrase when working with the younger highly informed bands (who are the greatest things that have ever appeared on this earth to grace our presence).
Title: Re: Problem removing frequency in monitor
Post by: Randall Hyde on December 12, 2012, 08:44:07 PM
I'd put a 31 band EQ on my wish list for Santa Claus.

Maybe even a parametric.

FWIW, I've never had to notch more than three frequencies out of a monitor mix to gain at least 3-6 dB additional gain before feedback in the monitors; even on some really weird stages. Usually, two frequencies suffice. However, I typically use a parametric EQ with a 0.1 octave bandwidth to avoid wiping out everything around the offending frequency.
cheers,
Randy Hyde
Title: Problem removing frequency in monitor
Post by: Samuel Rees on December 13, 2012, 04:41:18 AM
I think we are talking about the same concept.

Using your example, the 25db gain on the Beta (established from the trim) would be the "starting point" (not the 40db - hopefully no one would start it that hot) with the slider or aux-send turned all the way down... with the channel PFL showing (i.e) +3db with a vocal input.  Then more db is added to the signal as it's passed through the aux-send or fader.  Maybe another way of saying it, the 25db level at the input is (do I dare say) less sensitive than 40db. 

It just sounds like the OP may have an input level too hot for the offending freq. if they are unable to notch it out.  At lease rule out a "hot" input.
If the preamp is actually clipping, sure it could make feedback happen more easily, but assuming there is no clipping, it doesn't matter if you run the preamp a little hotter and the fader a little lower or fader a little higher and the preamp a little lower. Sorry if I'm beating a dead horse but you keep saying that we're on the same page, then saying something which makes it seem like we're not :)

Channel gain  = preamp gain +\- fader level. So 20 db of preamp gain and fader at zero/unity is 20 db of channel gain. 25 db of preamp gain and fader at -5 is the same thing. 10 db of preamp gain and fader at +10 is also the same thing. 3 different preamp gains - no change in 'sensitivity' to feedback or output level of any kind. Seems to me that you are suggesting that the 25/-5 combo is most susceptible to feedback than the other two because of a "hotter" trim, but this is not true.
Title: Re: Problem removing frequency in monitor
Post by: Robert Weston on December 13, 2012, 07:45:38 AM
If the preamp is actually clipping, sure it could make feedback happen more easily, but assuming there is no clipping, it doesn't matter if you run the preamp a little hotter and the fader a little lower or fader a little higher and the preamp a little lower. Sorry if I'm beating a dead horse but you keep saying that we're on the same page, then saying something which makes it seem like we're not :)

Channel gain  = preamp gain +\- fader level. So 20 db of preamp gain and fader at zero/unity is 20 db of channel gain. 25 db of preamp gain and fader at -5 is the same thing. 10 db of preamp gain and fader at +10 is also the same thing. 3 different preamp gains - no change in 'sensitivity' to feedback or output level of any kind. Seems to me that you are suggesting that the 25/-5 combo is most susceptible to feedback than the other two because of a "hotter" trim, but this is not true.

No, I was not suggesting the 25/-5 would introduce the most feedback (sorry if it came across that way); I was using it as an example.  What I was saying (referencing some bands), was not to use the preamps as a fader for their inputs, as many sometimes do; but, to keep the preamps down to a manageable level and use the sliders for +/- gain.
Title: Problem removing frequency in monitor
Post by: Samuel Rees on December 13, 2012, 11:17:17 AM
Haha ok, glad we're on the same page. Sorry to bog down the thread. Carry on.
Title: Re: Problem removing frequency in monitor
Post by: Tim McCulloch on December 13, 2012, 11:51:35 AM
No, I was not suggesting the 25/-5 would introduce the most feedback (sorry if it came across that way); I was using it as an example.  What I was saying (referencing some bands), was not to use the preamps as a fader for their inputs, as many sometimes do; but, to keep the preamps down to a manageable level and use the sliders for +/- gain.

Hi Robert-

Another way of describing this phenomena is "top knob mixing."
Title: Re: Problem removing frequency in monitor
Post by: Greg Bartusch on December 13, 2012, 06:30:03 PM
What do you mean by all the frequencies are pulled out? As in all the faders on the graphic are turned down? Because all that does is turn the whole level down and completely mess with the phase of the signal and give you way more problems.
Yes. All the frequencies are pulled down to the bottom of the EQ's
Title: Re: Problem removing frequency in monitor
Post by: Steve Garris on December 13, 2012, 06:45:20 PM
Yes. All the frequencies are pulled down to the bottom of the EQ's

When you do this it completely destroys the sound of that speaker. You need to start by setting all of the sliders at the indent, in the middle, and then carefully ring the system out by finding the offending frequencies, and cutting those frequencies only. Too much cutting of too many frequencies will not work, and the EQ is not designed to be used like that.

Better quality equipment (EQ's, Speakers) will give you less trouble. In some situations, you may never get the speaker to be loud enough without feedback. Sometimes the solution is mic placement and speaker placement. Get yourself a nice DBX 31 band graphic EQ - I'm sure you'll notice a difference.
Title: Re: Problem removing frequency in monitor
Post by: Ivan Beaver on December 13, 2012, 06:59:38 PM
Yes. All the frequencies are pulled down to the bottom of the EQ's
Well that's one way to destroy a system.  And a good indication of "not a clue".

Not only is the eq dropping the level in the system, it is also adding a lot of ripples in the response-where the filters overlap.

In this case the system would be MUCH MUCH  better WITHOUT the EQ!!!!!!!!!!!!!!

Title: Re: Problem removing frequency in monitor
Post by: Jay Barracato on December 13, 2012, 07:26:14 PM
Well that's one way to destroy a system.  And a good indication of "not a clue".

Not only is the eq dropping the level in the system, it is also adding a lot of ripples in the response-where the filters overlap.

In this case the system would be MUCH MUCH  better WITHOUT the EQ!!!!!!!!!!!!!!

I walked into a venue down near Atlanta and found the eq's on the mains set like that, the eq's on each channel set like that, AND a 15 band eq inserted on each channel set like that.

And found we had the third string house guy as a system engineer who was afraid to touch any of the boss's settings.
Title: Re: Problem removing frequency in monitor
Post by: Patrick Tracy on December 13, 2012, 08:06:21 PM
I walked into a venue down near Atlanta and found the eq's on the mains set like that, the eq's on each channel set like that, AND a 15 band eq inserted on each channel set like that.

And found we had the third string house guy as a system engineer who was afraid to touch any of the boss's settings.

I've been in this situation. The bypass button is usually my solution. Leave the stupid setting while getting better sound with no graphic eq at all.
Title: Re: Problem removing frequency in monitor
Post by: AllenDeneau on December 13, 2012, 08:36:24 PM
Explain how lowering the level at one end of the equation and raising it an equal amount at the other end results in a lower level.

Only on a system with a non centered fulcrum = see-saw with a much longer end on one side than the other ;)

I too was going to suggest a parametric eq BUT as was stated maybe running without an eq and limiting the input channels and mixes would be a better exercise for the op first?

IMO if he's not sure how to effectively work a graphic eq, won't a parametric just make things more difficult for him? I believe so.
Title: Re: Problem removing frequency in monitor
Post by: Ivan Beaver on December 13, 2012, 09:01:01 PM


IMO if he's not sure how to effectively work a graphic eq, won't a parametric just make things more difficult for him? I believe so.
At least (when in the habit of turning down) the Q control gets to be very narrow.  At least when the gain is turned down, the affected range of freq would be very narrow.  And then there would only be a couple of notches in the response-instead of screwing up the whole mix.

But again-unless it is used properly-the sound would be better WITHOUT it.

It is a common misconception that simply placing a piece of gear in a system will "somehow" make it better. NOT
Title: Re: Problem removing frequency in monitor
Post by: Steve Kas on December 14, 2012, 03:22:45 AM
I'm surprised y'all took this post serious. I doubt anybody, on this board, would turn ALL frequencies down on a graph. And, how does this guy "hear" 250 Hz? He must have some narrow band hearing that is extraordinary! Even the best parametrics cannot isolate 250Hz. A better post would had been:

"I am getting some low frequency feedback in my monitors. I tried "notching out" frequencies on my monitor graph, but the feedback still remained. Help!"

There are 100's of things that could be causing his "low frequency" feedback. A better reply would had been:

"Dude, consult a local professional audio engineer."

Done!   
Title: Re: Re: Problem removing frequency in monitor
Post by: Jay Barracato on December 14, 2012, 06:01:24 AM
I've been in this situation. The bypass button is usually my solution. Leave the stupid setting while getting better sound with no graphic eq at all.

My solution also.
Title: Re: Problem removing frequency in monitor
Post by: Ivan Beaver on December 14, 2012, 07:27:09 AM
I'm surprised y'all took this post serious. I doubt anybody, on this board, would turn ALL frequencies down on a graph.
Here is the problem.  Many of us have ACTUALLY SEEN this happen!!!!!!!!!!!!

It is NOT make believe.  It does happen.

And even if not ALL of them are turned down, once you get to a certain point-you need to flatten out and start over.

There are all kinds of photos floating around of really screwed up eq settings.  And "SOMEHOW" the person "in charge" of the system "thinks" this is fine or OK.

Just like many other audio "stupid things", this is just one of them.
Title: Re: Problem removing frequency in monitor
Post by: g'bye, Dick Rees on December 14, 2012, 08:47:43 AM
I'm surprised y'all took this post serious. I doubt anybody, on this board, would turn ALL frequencies down on a graph. And, how does this guy "hear" 250 Hz? He must have some narrow band hearing that is extraordinary! Even the best parametrics cannot isolate 250Hz. A better post would had been:

"I am getting some low frequency feedback in my monitors. I tried "notching out" frequencies on my monitor graph, but the feedback still remained. Help!"

There are 100's of things that could be causing his "low frequency" feedback. A better reply would had been:

"Dude, consult a local professional audio engineer."

Done!

I take it as seriously as I take yours.

Done.
Title: Re: Problem removing frequency in monitor
Post by: John Roberts {JR} on December 14, 2012, 09:34:13 AM
Perhaps automatic feedback killers are not such a bad idea for many people, and they will only get better over time.  As computers get cheaper and more powerful it is a natural progressing to offload tasks where the decision making can be programmed to follow simple rules.

It is human nature to think we are are all irreplaceable, but over time we all get replaced. Some by technology, some by younger meat puppets.

JR
Title: Re: Problem removing frequency in monitor
Post by: Tim Perry on December 14, 2012, 10:05:43 AM
Here is the problem.  Many of us have ACTUALLY SEEN this happen!!!!!!!!!!!!

It is NOT make believe.  It does happen.



Sometimes DJ's turn all of then all the way up.... gotta make it louder right?
Title: Re: Problem removing frequency in monitor
Post by: Curtis H List (Too Tall) on December 14, 2012, 12:12:15 PM
+1. The max number of bands I'll cut on a 31 band EQ is 4-6.  That means after you pull down 2 or 3 faders on your 15 band EQ then STOP.  Any more adjustments and you are trashing the sound and causing other problems.

I'd put a 31 band EQ on my wish list for Santa Claus.

Another reason you may find that you are pulling more frequencies then you should is the gain in the crossover for one or all drivers is wrong.

Imagine the speaker is active and bi-amped. On the crossover or the gain knob on the power amp you can change the gain of each driver.
You ring out the PA and find you are dropping every EQ fader from 1kHz to about 6kHz.
What this would tell me that the horn was too loud, not that it had a bunch of peaks in the highs. So push all the faders back to zero and turn down the highs on the crossover.
If you get it right you should have some faders above and some below with a few hotter peaks thrown in.

Beyond this if the speaker has a passive crossover and you have the same problems this again points to the crossover, but you cannot get at the crossover.

20 years ago this often was the problem. Using generic crossovers that only protected the drivers and did not fix any of their problems.
In this day and age you should not have this problem as long as you use speakers made in the last 10 years and had decent reputations.

As for the EQ you are using you are killing yourself with no improvement.

IF you buy expensive monitors that are supposed to be flat out of the box and you use an expensive vocal mic that does not need EQ out of the box you should not need much of an EQ on the monitor speaker.

Another way to approach this is at the FOH vocal mic channel.

Typical setup when running monitors from your FOH board is to set the routing for Pre-EQ so when you did something at the FOH it did not screw with the monitors. In this case I suggest you do not have the correct EQ (1/3rd Oct) so we need to take a chance.

Either set the vocal channels monitor for post-EQ or shift the monitors to an effects AUX that is already Post-EQ.
Try this and be careful.
I know people that do this all the time, but their monitor’s speakers are very good.

If the EQ on the vocal channels is limited and sounds like crap the only thing left is to look for and buy a vocal mic that needs no EQ from 100Hz to 6kHz.
Above and below that you can use your 15-band.

In the end this is what I did. I bought Beyer Ribbon M-500 mics for primary vocals and Beyer 400 dynamic for backup vocals for a bar band like yours.
Though it may look too expensive a solution, it solves a bunch of problems while using the Live Sound Maxim “Fix it at the source”.
In the end you will most likely need to buy 1/3rd Oct EQ.

Something to keep in mind with all graphic EQs.
The graphic EQs are supposed to “draw you a picture” of what the EQ is doing.
This is TOTALLY WRONG! They are lying to you.
Use a RTA. There are several free ones around that run on laptops.
Try this one-
www.libinst.com

Download the program Praxis and install the free demo version.
Unhook the EQ from the rest of the system.
Praxis in the free demo version will generate pink noise and it will measure with its RTA.

One thing you must remember is that when you feed the signal back into the laptop it goes into a soundcard.
This is set up to take microphone level or home audio (-20dB) and you are going to feed it line level (+4dB). This may be dangerous.

The totally safe thing is to put a high value (10k ohms) resistor on the hot wire going from the output of the EQ back into the laptop sound card IN.

Other than that you can cut down the gain on the EQ, IF it has a master gain adjustment.
I like the resistor.

The whole reason for this is for you to see what happens when you cut two EQ faders that are next to each other. See what kind of hole it digs compared to the picture you see on the front of your “graphic” EQ.
You will be shocked how badly it chops things up along with how much gain you have lost. Since we are using an RTA that can not measure Phase you can not see how bad that is screwed around, though the result does show up as gain loss when two faders are cut near or next to each other.

I strongly suggest you do this test so you can see how bad things get with a minor cut of EQ, never mind pulling all the faders down near the bottom.

Make up some y-cords so you can monitor the EQ during setup and during the show.

Have a Merry Christmas,
Too Tall

Title: Re: Problem removing frequency in monitor
Post by: Patrick Tracy on December 14, 2012, 12:22:25 PM
The whole reason for this is for you to see what happens when you cut two EQ faders that are next to each other.

Not pairs of sliders, but there are some "Death to 100" curves here: http://bouldersoundguy.com/fr-curves.01.html
Title: Re: Problem removing frequency in monitor
Post by: Greg Bartusch on December 17, 2012, 04:54:37 PM
I'm surprised y'all took this post serious. I doubt anybody, on this board, would turn ALL frequencies down on a graph. And, how does this guy "hear" 250 Hz? He must have some narrow band hearing that is extraordinary! Even the best parametrics cannot isolate 250Hz. A better post would had been:

"I am getting some low frequency feedback in my monitors. I tried "notching out" frequencies on my monitor graph, but the feedback still remained. Help!"

There are 100's of things that could be causing his "low frequency" feedback. A better reply would had been:

"Dude, consult a local professional audio engineer."

Done!

You are right. Your subject is correct. I do know how to ring out pa systems. Here's my thing. I've been getting suggestions to ring out the monitors. I can do this when there is no band on stage, but once a band is playing, it's a whole different ballgame. The stage is small, with the drums and guitars bleeding through the mics, that's when the feedback starts. Then I start pulling out frequencies. I've got bands this weekend and I'm going to ring out the monitors beforehand.
Title: Re: Problem removing frequency in monitor
Post by: g'bye, Dick Rees on December 17, 2012, 05:20:00 PM
I've got bands this weekend and I'm going to ring out the monitors beforehand.

Using what?  Have you gotten something that will actually work or are you going to continue with the 15 band stuff?
Title: Re: Problem removing frequency in monitor
Post by: Steve Kas on December 19, 2012, 02:45:19 AM
First, respectfully reply to exactly what I posted in respect to this thread.

1. Turning down ALL frequencies on a graph is not prudent. That's why there is gain and the concept of signal structure.

2. There is not an EQ that can isolate 250 HZ without affecting 251, 249, 250.3 Hz etc.. Hence, an exact "250 HZ feedback" couldn't be fixed even if an individual had super-human hearing.

Now, the question of feedback resolution.

"Ringing" monitors cannot fix most variables that can cause unpleasant feedback on stage. Some engineers will "mix" to avoid feedback rather than providing the artist with optimal monitoring of the performance. I've seen soundmen pull 1K, etc.. out of a wedge's mix because it was "feeding back"! Great! No more feedback- but now the singer is going to want more volume because his voice is less intelligible! So, the sound guy turns up the send. Now, low mid and high frequencies start ringing! So, what does  he do? Pulls those down too! Finally, he ends up with an EQ that looks like many of you have seem in the past Nightmare! And, after all that work, the monitor mix still sounds like a**!

So, what should you do? This advice applies to vocals only.

1. Make sure all your wedges on the deck are the same as your reference wedge in monitor world or at the house.

2. Run some nicely mixed pre-recorded music through your reference wedge and EQ to your taste.

3. EQ their channel to your taste in a good pair of reference headphones before listening to it in your reference wedge.

4. Listen to their channel through your reference wedge and make minor adjustments in EQ that suit your taste. I strongly suggest having the artist play a song while you do this. I tell them that they will not hear anything in their mix during this time. Most are ok with this provided you can EQ your reference wedge quickly!

5. Slowly bring up the mix in their wedge. They will give you a "thumbs up" or a head nod, etc..

6. Ask anybody on stage to either get off stage or cover their ears. Go on stage and face the mic directly at the wedges speakers while standing. If no feedback, cool!! If feedback,turn mix send down. Try again. Then, hold mic to your mouth like you were singing and kneel down in front of wedges (cover 1 ear!!). If no feedback, cool! If feedback, lower mix send. DO NOT CUT FREQUENCIES at this point. Trust your ears.

7. Ask artist to play again. If the artist says, "I can't hear myself." Tell them to turn down their stage volume to a level that he/she can hear and begin thinking about where you can get some money to buy better gear! These guys will probably never hire you again. But, atleast you got the best from the gear you have. If the artist says, "Yeah! Sounds good!" Expect future biz!

Like I said before, there are too many variables that can affect a monitor mix and cause feedback to possibly post on this board. They are unique to any situation. However, I hope my 7 point advice might give you a good starting point. Cheers.   

 
Title: Re: Problem removing frequency in monitor
Post by: Roland Clarke on December 19, 2012, 05:37:48 AM
First, respectfully reply to exactly what I posted in respect to this thread.

1. Turning down ALL frequencies on a graph is not prudent. That's why there is gain and the concept of signal structure.

2. There is not an EQ that can isolate 250 HZ without affecting 251, 249, 250.3 Hz etc.. Hence, an exact "250 HZ feedback" couldn't be fixed even if an individual had super-human hearing.

Now, the question of feedback resolution.

"Ringing" monitors cannot fix most variables that can cause unpleasant feedback on stage. Some engineers will "mix" to avoid feedback rather than providing the artist with optimal monitoring of the performance. I've seen soundmen pull 1K, etc.. out of a wedge's mix because it was "feeding back"! Great! No more feedback- but now the singer is going to want more volume because his voice is less intelligible! So, the sound guy turns up the send. Now, low mid and high frequencies start ringing! So, what does  he do? Pulls those down too! Finally, he ends up with an EQ that looks like many of you have seem in the past Nightmare! And, after all that work, the monitor mix still sounds like a**!

So, what should you do? This advice applies to vocals only.

1. Make sure all your wedges on the deck are the same as your reference wedge in monitor world or at the house.

2. Run some nicely mixed pre-recorded music through your reference wedge and EQ to your taste.

3. EQ their channel to your taste in a good pair of reference headphones before listening to it in your reference wedge.

4. Listen to their channel through your reference wedge and make minor adjustments in EQ that suit your taste. I strongly suggest having the artist play a song while you do this. I tell them that they will not hear anything in their mix during this time. Most are ok with this provided you can EQ your reference wedge quickly!

5. Slowly bring up the mix in their wedge. They will give you a "thumbs up" or a head nod, etc..

6. Ask anybody on stage to either get off stage or cover their ears. Go on stage and face the mic directly at the wedges speakers while standing. If no feedback, cool!! If feedback,turn mix send down. Try again. Then, hold mic to your mouth like you were singing and kneel down in front of wedges (cover 1 ear!!). If no feedback, cool! If feedback, lower mix send. DO NOT CUT FREQUENCIES at this point. Trust your ears.

7. Ask artist to play again. If the artist says, "I can't hear myself." Tell them to turn down their stage volume to a level that he/she can hear and begin thinking about where you can get some money to buy better gear! These guys will probably never hire you again. But, atleast you got the best from the gear you have. If the artist says, "Yeah! Sounds good!" Expect future biz!

Like I said before, there are too many variables that can affect a monitor mix and cause feedback to possibly post on this board. They are unique to any situation. However, I hope my 7 point advice might give you a good starting point. Cheers.

And this is it, in a nutshell!

"Ringing out" monitors is like taking a sledge hammer to a nut.  Good smooth monitor sound shouldn't feed back given, reasonably sensible monitor levels, sensible positioning of monitors with due defference to the microphones polar patern and a decent mix.

The only time I "ring out" monitors, is to discover problem frequencies that are down to stage resonances from things like standing waves, that's not to say that I leave them pulled out, I still look for solutions such as repositioning or a subtle adjustment of monitor eq, though nothing that drastic.

As pointed out, particularly on smaller stages, other issues such as the monitor angle can effect the way that musicians hear themselves.  Often musicians will stand so close to the monitor the sound is firing at their belly and not even close to their ears, hence my suggestion for sidefills as an option for dealing with this.  Obviously YMMV as may others.
Title: Re: Problem removing frequency in monitor
Post by: Curtis H List (Too Tall) on December 20, 2012, 08:57:01 PM
And this is it, in a nutshell!

"Ringing out" monitors is like taking a sledge hammer to a nut.  Good smooth monitor sound shouldn't feed back given, reasonably sensible monitor levels, sensible positioning of monitors with due defference to the microphones polar patern and a decent mix.

The only time I "ring out" monitors, is to discover problem frequencies that are down to stage resonances from things like standing waves, that's not to say that I leave them pulled out, I still look for solutions such as repositioning or a subtle adjustment of monitor eq, though nothing that drastic.

As pointed out, particularly on smaller stages, other issues such as the monitor angle can effect the way that musicians hear themselves.  Often musicians will stand so close to the monitor the sound is firing at their belly and not even close to their ears, hence my suggestion for sidefills as an option for dealing with this.  Obviously YMMV as may others.

Good points.
If you have to use active xovers with controls people can get at ring out becomes a necessity to see if the xover is still set to the settings it should be.
This is used because they don't have Smaart.
If you are outdoors or in a building with at least a 30ft ceiling anyone should be able to get enough gain before feedback.

Recall we are in the "LAB Lounge".
If you are on a bar stage with the ceiling is less then 7 feet it becomes an intractable problem. Especially if the band is loud.
Also you seldom have high quality wedges and mics. Even a 1/3rd Oct EQ is often a luxury.

On pulling down the EQ faders more than you should. If you have 5 nights in the same place and the weather changes you keep chopping away at the main EQ till the average line goes further down every night.
How many here have found themselves moving the whole curve up above zero and starting from scratch on the third night?


Title: Re: Problem removing frequency in monitor
Post by: John Roberts {JR} on December 21, 2012, 09:43:34 AM
One piece of misinformation that has crept in, is that correcting feedback cuts holes in the frequency response. Properly done, corrective EQ flattens out peaks or bumps in the response, for a flatter result.

Of course using an axe (2/3rd octave) to trim your toe nails, could lead to loss of toes. :-(

JR
Title: Re: Problem removing frequency in monitor
Post by: Ivan Beaver on December 21, 2012, 11:07:16 AM
One piece of misinformation that has crept in, is that correcting feedback cuts holes in the frequency response. Properly done, corrective EQ flattens out peaks or bumps in the response, for a flatter result.

Of course using an axe (2/3rd octave) to trim your toe nails, could lead to loss of toes. :-(

JR
Of course there are actually 2 basic sources of "peaks" in the response that need to be flattened out.

The loudspeaker is one (and yes a flat response is the best place to start (and usually works just fine).

The second is the peaks in the response of the open mic.  So when you add the two  together you could end up with some nasty stuff.  Or not-depending on the response of each.

It is also a misconception that you HAVE to ring out the mics.  If the system gets loud enough for use without ringing out the system (and also sounds fine), then there is no real reason to "ring it out".

As always- just because it CAN be done-does not mean it HAS to be done.
Title: Re: Problem removing frequency in monitor
Post by: John Roberts {JR} on December 21, 2012, 11:52:00 AM
Of course there are actually 2 basic sources of "peaks" in the response that need to be flattened out.

The loudspeaker is one (and yes a flat response is the best place to start (and usually works just fine).

The second is the peaks in the response of the open mic.  So when you add the two  together you could end up with some nasty stuff.  Or not-depending on the response of each.

It is also a misconception that you HAVE to ring out the mics.  If the system gets loud enough for use without ringing out the system (and also sounds fine), then there is no real reason to "ring it out".

As always- just because it CAN be done-does not mean it HAS to be done.

There is a third source of frequency response bump(s) caused by the signal repeating and constructively (and destructively) summing with itself (at frequencies related to path transit time and signal wavelength).

From whatever source, reducing feedback generally flattens the system. Of course significantly non-flat off-axis response in the vector between mic and speaker can reduce normal path system flatness at extremes of GBF tweaking. 

This is either engineered(?) or has been discovered empirically with mic/monitor speakers that play nice together. Feedback is the product of these path response phenomenon "and" system response, so a perfectly flat system can still feedback, and a non-flat system might work OK depending on where it is not flat.

All things equal, flat is a good initial condition.

JR
Title: Re: Problem removing frequency in monitor
Post by: Patrick Tracy on December 21, 2012, 01:21:33 PM
I've found that if you start off with wedges that measure flat they will sound louder right off the bat because nothing is missing. With a bumpy response you can turn up to the point that it's feeding back at a response peak but the musician still needs more to hear what's in the troughs.

If you do get the speakers flat but you have to turn up to the point of feedback then the frequencies you're cutting are either mic or room issues. I consider that the boundary between reasonable stage volume and high stage volume.