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'Ringing Out' monitors
Old 7th July 2009
  #1
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audiothings's Avatar
 

Question 'Ringing Out' monitors

Relative noob at live sound...

when using condensers on stage (not the beta 87 close vocal types), be it for instruments, or on the podium, or hanging from the ceiling grid, or used as head worns, i find that i am eq'ing out too many frequencies to keep feedback at bay... i don't even seem to have one second to figure out what the first feedback frequency is before a couple more have sprung up... and everybody is hollering at me while this is happening... it ain't no pleasant sound as everybody knows

anybody care to give me some tips on how to move minimum eq bands and get maximum feedback rejection?

thanks,
Old 7th July 2009
  #2
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Roland's Avatar
Feedback occurs because the sound from the monitors comes back to the diaphragm of the mic louder than the original thus giving you the "ringing" or "howling" sound we are all familiar with. So to prevent that you need to make sure this isn't happening.

You mentioned that these are condenser microphones, however you don't say which models you are using. General rule is that mic's not specifically designed for stage use will have a less tightly tailored pattern and therefore give you less GBF (gain before feedback). When it comes to monitor speakers you can "ring out" the speaker by increasing the gain till it just starts to feedback then looking at the frequency on a RTA analyzer and then reduce that on a graphic feeding that monitor. I personally don't do that unless we are getting problems. If you are getting a good quality, even sound monitors can go plenty loud enough without feedback. This brings us to the second issue. The biggest cause of feedback problems with monitors IMHO are bands playing too loud or out of balance on stage. There is absolutely no need for this and usually displays a lack of professionalism from the players and/or monitor engineer. Monitors are there to let a musician hear himself in balance with the other players on stage so that he/she can deliver his/her performance.

The finer points of monitor engineering can be discussed at length, it's a very broad subject and a complete area of audio engineering on it's own, but the best place to start is an understanding of how polar patterns on mics effect feedback susceptibility and an understanding of what you are trying to achieve with onstage monitoring being the most useful places to start.

If you can give specific details about what mic's you are using and the particular application I can possibly offer some more detailed advice.

Regards


Roland
Old 7th July 2009
  #3
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Given your other post I am assuming this is involving your musical theatre work. You're using Countryman E6's and lav mics, correct? These are typically omnidirectional mics so you're really not going to get the monitors screaming loud. Make sure the "talent" knows that they are not going to hear their voice at 100 dB in the monitors. Actually, they shouldn't need to hear themselves in foldback at all. They should learn to project as if they weren't wearing a mic at all. Having them loud in the monitors will only cause them to talk more softly, causing you all kinds of problems. Monitors in theatre should be for cueing purposes (tracks, instruments if necessary, SFX, etc.), not for indulging your own ego trip (that's what rock band monitors are for).
Old 7th July 2009
  #4
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Tuning monitors correctly, especially for headworn mics and lavs, takes lots of practice. If you are finding that you are cutting every frequency, all you've really done is turned the gain down, defeating the purpose of making the monitors louder. Don't be afraid to take deep cuts of problematic frequencies, but at the same time remember to put frequencies back if its not doing what you need it to do. Also keep in mind that most problem frequencies don't occur at just one frequency. They usually occur in a range of frequencies that will result in you needing to take, say 6 dbs out at 500, and 2 dbs out at 400 and 630 (for example). Smoothing out the correct frequency ranges can also affect how other nearby frequencies react. So in the previous example, if those cuts worked for you, you may be able to put back some 315 or 800 to beef it back up (if you had taken those freqs out before).

I will say that proper gain structure is of utmost importance. Keep your amps as low as possible and send a hotter signal to them from the console. If you send a weak, anemic signal to a cranked power amp, you're just amplifying a bad signal and it will never sound right. Sending a strong, healthy signal to a properly gained amp will result in a better, louder sound that is easier to EQ. Trust me on that one.

Don't forget about monitor positioning. If the wedge is blowing into the performer's knees, you're fighting a losing battle.
Old 7th July 2009
  #5
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Quote:
Originally Posted by PoorGlory View Post
Don't forget about monitor positioning. If the wedge is blowing into the performer's knees, you're fighting a losing battle.
This seems so obvious but look at the Clair 12AM. It's such an industry standard but completely the wrong angle for up close monitoring. A couple of wood shims can take care of it, but why should I have to carry 2x4's to get the monitors pointed at my face?
Old 7th July 2009
  #6
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Quote:
Given your other post I am assuming this is involving your musical theatre work.
somewhat correct. the most recent situation. i had a six month gig as house engineer at a concert hall until early this year. We had similar problems with the SDC mics we used there, under various circumstances. something is lacking in my technique and i am trying to find what exactly it is...
Quote:
You're using Countryman E6's and lav mics, correct?
In this case, correct, but as above...

Quote:
Make sure the "talent" knows that they are not going to hear their voice at 100 dB in the monitors. Actually, they shouldn't need to hear themselves in foldback at all. They should learn to project as if they weren't wearing a mic at all. Having them loud in the monitors will only cause them to talk more softly, causing you all kinds of problems. Monitors in theatre should be for cueing purposes (tracks, instruments if necessary, SFX, etc.), not for indulging your own ego trip (that's what rock band monitors are for).
been there, done that exactly! for dialog, i have automated the scenes so that the monitors don't come on at all... for music (we are playing minus one tracks for the most part) i have to keep the monitors on, only so that the singers can stay in pitch and time, no more volume on the monitors than necessary...
Quote:
say 6 dbs out at 500, and 2 dbs out at 400 and 630 (for example). Smoothing out the correct frequency ranges can also affect how other nearby frequencies react. So in the previous example, if those cuts worked for you, you may be able to put back some 315 or 800 to beef it back up (if you had taken those freqs out before).
sure you are right...
Quote:
increasing the gain till it just starts to feedback then looking at the frequency on a RTA analyzer and then reduce that on a graphic feeding that monitor.
blimey! why on earth did not think of using the RTA? we had one on board! (actually i know why... at the concert hall, the systems engineer told me to "use your ears, RTA is for wusses")...

will report back by the end of the month (we have 3 more shows at other venues...) after using the RTA to tune the monitors and the PA. Hopefully it should help me isolate the real problem frequencies...

keep 'em coming...
Old 7th July 2009
  #7
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Quote:
Originally Posted by bishopthomas View Post
This seems so obvious but look at the Clair 12AM. It's such an industry standard but completely the wrong angle for up close monitoring. A couple of wood shims can take care of it, but why should I have to carry 2x4's to get the monitors pointed at my face?
Those shouldn't be right at the artists feet, they should be a few feet in front of them. Having monitors right at the performer's feet shooting straight up is putting the monitor mix further on axis with vocal mics (assuming standard cardioid vocal mics a la the SM58), so there's more potential for feedback right there.

I know that doesn't always play out that way in cramped stage conditions, but that's what it is.
Old 7th July 2009
  #8
I am sure this goes without saying, but the mic's need to be close to whatever is being ampified. Running a "distant" condenser mic through stage monitors is asking for trouble.

Also, whenever possible, the monitor should be in the null of whatever mic you are using. So if you are using a super cardioid mic, but placing the monitor in the 180-degree position as you would for a cardioid, you will probably have feedback issues.

If you find yourself cutting more than a couple of frequencies on the graphic, then something is wrong somewhere else in the chain - mic position, gain structure, or just pushing the system further than it can go.

If the system is being pushed beyond what it can do, adding speakers and/or reducing the number of open mic's can help.
Old 7th July 2009
  #9
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Roland's Avatar
Quote:
Originally Posted by audiothings View Post
somewhat correct. the most recent situation. i had a six month gig as house engineer at a concert hall until early this year. We had similar problems with the SDC mics we used there, under various circumstances. something is lacking in my technique and i am trying to find what exactly it is... ...

I suspect you are trying to provide monitors for things that don't need monitors. For example your vocalist on E6's, just pump enough of the track through the monitors to give them enough to tune and time too.



Quote:
been there, done that exactly! for dialog, i have automated the scenes so that the monitors don't come on at all... for music (we are playing minus one tracks for the most part) i have to keep the monitors on, only so that the singers can stay in pitch and time, no more volume on the monitors than necessary...
This they don't need their own sound in the monitors for.




Quote:
blimey! why on earth did not think of using the RTA? we had one on board! (actually i know why... at the concert hall, the systems engineer told me to "use your ears, RTA is for wusses")...
And that makes him the amateur. Sure you should know your frequencies, however, if something is 100 or 80 hz can be a big difference in terms of tunning the rig/monitors right, but difficult to spot cold. RTA is a sure fire way of seeing what is going on, FFT systems like Smaart are really useful too, lots of useful information can be garnered from them.



Quote:
will report back by the end of the month (we have 3 more shows at other venues...) after using the RTA to tune the monitors and the PA. Hopefully it should help me isolate the real problem frequencies...
The above pointers should get you started, but always ask yourself the questions first, "What is it that I am trying to achieve? What do I need to do to achieve this?" If you approach all your sound work like this, you will gain a reputation as a problem solver.

Good luck!

Regards


Roland
Old 7th July 2009
  #10
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Using the RTA will make everything sound better and more intelligible too. Because of that you'll need less level.
Old 8th July 2009
  #11
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I find that with a really well tuned monitor system, feedback isn't a huge issue. When I'm tuning the system, I go for flat. Not just gain before feedback. I'll actually use a parametric EQ to get the few nasty frequencies and then a graphic for the couple problematic ones. With many of the graphics out there, a huge cut will really adversely affect the sound of the speaker from phase shift.

I've had some screaming monitors with condenser mics and not had them feedback with this formula.

Now- nothing will change the fact that you still need some degree of mic technique. If you have singers that cup vocal mics (most often in hip hop shows), you change the polar pattern and make more of a chance of feedback. Also, if you point a mic towards the monitor, you can have issues as well.

As mentioned earlier, headset mics and lavs are another issue. Being that they are usually omni mics, careful EQ of the microphone is a necessity. This just requires practice. You aren't likely to have monitors quite as loud in this situation, but you should still be able to do pretty well.

Lastly- as mentioned earlier. Make sure your monitors are actually aiming towards the performer. To have it aiming overhead or to the performer's knees don't do anybody any good. Have a couple blocks (or heck- rolls of 2" tape) to prop it up.

--Ben
Old 8th July 2009
  #12
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i still belive using an RTA to tune monitors is cheating yourself. its the same as a DJ using BPM counters.... your not taking the time to train your ears.

a 31 band graphic, and the parametric is all it takes to sort out wedges. even with lapel mic, even at a decent volume. its all about your technique and your skill. and unfortunatly its a case of practice makes perfect

the biggest factor of getting monitors right is gain structure, and heres another little trick, avoid long release times on any compressors
Old 8th July 2009
  #13
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Roland's Avatar
Quote:
Originally Posted by jude View Post
i still belive using an RTA to tune monitors is cheating yourself. its the same as a DJ using BPM counters.... your not taking the time to train your ears.
Every engineer should train their ears and I'd ve the first to say "know your frequencies", but knowing there is a problem around 6-8k is one thing, the RTA will show you very accurately exactly where the problem lies and you can see other problems that maybe you can't quite hear. I can and have teched out more rigs than I can mention without rta or smaart, however, these tools are like a tape measure, it helps to be as accurate as possible.

Quote:
a 31 band graphic, and the parametric is all it takes to sort out wedges. even with lapel mic, even at a decent volume. its all about your technique and your skill. and unfortunatly its a case of practice makes perfect
Of course, but there are applications where you don't need to be putting stuff through the monitors and knowing when not too is also a trick.

Quote:
the biggest factor of getting monitors right is gain structure, and heres another little trick, avoid long release times on any compressors
Absolutely! There are no easy fixes. It's the right fix for the right application.

Regards



Roland
Old 8th July 2009
  #14
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Problem with an RTA is that it isn't going to help you when the vocalist's wedge is on edge during a show and you need to identify and fix a problem. It also isn't going to help you if the speakers are not placed correctly.

I tune by music that I know well. I play music through the system (mains or monitors) and EQ as I hear and see fit (Hence the parametric). If time permits, I'll throw a few mics out on stage to make stuff feed back so that I know where my problem spots will be.

--Ben
Old 8th July 2009
  #15
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Quote:
I suspect you are trying to provide monitors for things that don't need monitors. For example your vocalist on E6's, just pump enough of the track through the monitors to give them enough to tune and time too.
thank you roland, but are you sure of this?

vocalists don't need to hear their own voices over the monitors to stay in tune? many of the vocalists i work with are asking for reverb on their voices, in the monitors!!! you are a lucky man if you have such understanding singers who will agree to have their voices bypassed for the minitor mixes!
Old 8th July 2009
  #16
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Roland's Avatar
Quote:
Originally Posted by audiothings View Post
thank you roland, but are you sure of this?

vocalists don't need to hear their own voices over the monitors to stay in tune? many of the vocalists i work with are asking for reverb on their voices, in the monitors!!! you are a lucky man if you have such understanding singers who will agree to have their voices bypassed for the minitor mixes!

People have been singing in tune for centuries, long before we had monitors, in fact prior to the Sixties I think you will find monitors for stage probably didn't exist. Wanting verb in monitors is a particularly amateurish trait amongst performers. That will lead to feedback problems. If there is verb on the FOH and the reflections from the auditorium that should be plenty. I had this discussion with a well seasoned session guitarist, working a show with a couple of vocalists that wanted verb in the monitors. His attitude was that they were obviously amateurs as anyone knows it's asking for problems. In ear monitor systems are of course different.

Regards



Roland
Old 8th July 2009
  #17
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Quote:
Originally Posted by fifthcircle View Post
Problem with an RTA is that it isn't going to help you when the vocalist's wedge is on edge during a show and you need to identify and fix a problem. It also isn't going to help you if the speakers are not placed correctly.
Actually it will, you can see it spike on the display at the problem frequency, straight to a graphic or parametric and notch it out.

Quote:
I tune by music that I know well. I play music through the system (mains or monitors) and EQ as I hear and see fit (Hence the parametric). If time permits, I'll throw a few mics out on stage to make stuff feed back so that I know where my problem spots will be.

--Ben
Tunning rigs by ear often works, but it can be difficult to spot particular problems, Smaart and alike will often show them up straight away. Of course having used a system tunning tool it goes without saying you should then listen to material you are very familiar with and make adjustments to taste.


Regards


Roland
Old 10th July 2009
  #18
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As Roland said, feedback occurs when the signal comes back into the mic.

Aiming mics away from monitors helps a lot, but there is another important thing and that is when you're eq-ing.

People eq-ing for feedback, kill the monitor in a way. You take out the freq that feeds back, turn the level up, point the mic in the wedge, pick out the next freq and so on. That way you take out all frequencys nescecery for the musician to hear themselves. So they want it really loud and even louder and then the wedge is so loud it feeds back and you'll have to eq more and turn it up and feedback blah...



If you eq the monitor for the sound of the monitor itself so it sounds good and got over problems like standing waves in the room, you can put much more level level without pushing too much. If you don't need it too loud, you won't have feedback problems!
Old 10th July 2009
  #19
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Quote:
Originally Posted by trompetfreak View Post
As Roland said, feedback occurs when the signal comes back into the mic.

Aiming mics away from monitors helps a lot, but there is another important thing and that is when you're eq-ing.

People eq-ing for feedback, kill the monitor in a way. You take out the freq that feeds back, turn the level up, point the mic in the wedge, pick out the next freq and so on. That way you take out all frequencys nescecery for the musician to hear themselves. So they want it really loud and even louder and then the wedge is so loud it feeds back and you'll have to eq more and turn it up and feedback blah...



If you eq the monitor for the sound of the monitor itself so it sounds good and got over problems like standing waves in the room, you can put much more level level without pushing too much. If you don't need it too loud, you won't have feedback problems!

As Philip says above "ringing out" monitors can lead to it's own problems, getting a monitor to sound good, often means that you need less.

Many times I've worked with monitor engineers who have rung out the monitor system, however, this leads to monitors that a) don't sound that good and need to be louder for the artist to hear, b) are pushing back a lot of poor quality stage mush that is throwing out the balance of the sound on stage with poor quality stage wash, which in turn effects the quality of the sound FOH.

IMHO the first thing woth stage monitors is to get the band to play as much in balance on the stage as possible (turn that f*@king guitar amp down!) . Secondly to find out what the artist wants to hear, then give them what (this is where the real skill comes in) they NEED!

Also consider what frequencies are wanted in the monitors, for starters you often don't need much low end as frequently this will wash back from FOH. It's all a balancing act.

Many times I also see monitor engineers pushing faders up and down like a yoyo, again this can be detrimental as the artist is always receiving an artificial balance. Give them a good balance, then let them work the balance with their own dynamics, i.e. aguitarist comes to play a solo, he plays up a little, because the balance (hopefully) is good he gets a little more back in the monitor and pushes against that. Now you have a musician who is able to get a real feel for what they are doing and can interract with his fellow band members in the most musical way, letting them get a real "vibe" going.

This is my personal view, of course YMMV.

Regards


Roland
Old 10th July 2009
  #20
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nice we agree, Roland!

gr. ph.
Old 10th July 2009
  #21
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Quote:
Originally Posted by mixedupsteve View Post
Using the RTA will make everything sound better and more intelligible too. Because of that you'll need less level.
I find most systems setup with RTAs tend to be over EQed. Use your ears and learn to identify resonances and frequencies. You'll be better off.
Old 10th July 2009
  #22
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Roland's Avatar
Quote:
Originally Posted by TinderArts View Post
I find most systems setup with RTAs tend to be over EQed. Use your ears and learn to identify resonances and frequencies. You'll be better off.

This is, I am afraid, misinformed. What can be done with modern speaker management is to say the least impressive.

I've heard of demo's where one of a stereo pair of speakers was turned round to face the wall and the speaker management system was able to compensate enough to generate a passable stereo image. this is not just frequency balance, but phase response as well. Fortunately the systems can't mix the band for us or we would be all out of a job, but they can take measurements much more accurately and faster than we can ever hope to.

Simply put, given the choice between a system properly teched out with Simm or Smaart then give the once over by me or a system purely teched out by "ear" using my favorite tracks it's a no brainier. Every major music festival and serious tour/show is teched this way, whatever people might think, live sound is better today than it has ever been.

Regards


Roland
Old 11th July 2009
  #23
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Quote:
Originally Posted by TinderArts View Post
I find most systems setup with RTAs tend to be over EQed. Use your ears and learn to identify resonances and frequencies. You'll be better off.
I'm pretty good at using my ears and don't use the RTA often actually. But I've found it works great in problem rooms and when there's not much time it's a blessing. I don't totally rely on it. Just because someone uses a new tool doesn't mean they don't know how to use any others.
BTW, where are you in Bowie? I lived there until 3 years ago.
Steve
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