Parametric Eq and notching frequency

[SOUND PROOF]

I did a gig around Christmas with a double bass player and a flute and me on guitar and vocals. Me and the bass player ran into a woofy issue, it seemed that when I started to play middle A on my guitar (7th fret 4th string) or (D 5th fret 5th string) and the bass player was playing either one of these notes, we got a woofy resonance that got out of control. We were playing outside in front of a garage about 20 feet from a carport and 30 feet from the corner of the house. I am assuming that this issue had something to do with the mathematics of the architecture and the frequency of the tone. A friend told me that a parametric eq, he said it would solve this problem, I would simply take out the frequency that was in question. If you have any discussion on this please discuss away. I am sure I am just starting to scratch the surface on understanding the math of frequency.

[agedhorse]

Taking a little bit out will certainly mask the problem if not "correct" it. The problem may be due to the physical layout between the speakers, the instruments and summing similar frequency signals that may be in and out of phase.

 

So the answer is "it depends".

[Dogoth]

I have a similar setup going with my monitor system. The stage I work on has a standing wave at 212 hz. I have a very narrow notch (-6db) setup on the output parametric of each mix as part of my starting template. It helps but to eliminate the ring totaly I must notch around -16db or more. This makes everything sound unnatural and thin so I have found the tradeoff point. Over all it's a great sounding stage and there are times where a performer wants more "body" in their mix and I put some or all of it back. The only way to really fix acoustic problems is through Room design, acoustic treatment & placment. Electronics is the quick fix (and IMO not really a very good one).

[Shaster]

Last Thursday, on my New year's Eve gig, C# was ringing in the monitors (I wasn't running sound). I had played that particular club hundreds of times spanning over twenty years, and never had that problem.

 

So even if that resonant frequency was inherent to the room and/or system, all the previous techs had no problem dialing it out. The tech in question was new to the room and had changed something somewhere.

 

So... a parametric or graphic equalizer could help with your "woofy" problem but you might be able to solve it by other means. And as noted, just watch that you don't radically change the timbre of any particular instrument or voice, when you start chopping or notching frequencies.

 

Just curious, was your PA fairly decent (mics, speakers, mixer...), and were you running subs? Was the bass miced or using a bridge pick-up? Were you using an electric or acoustic guitar?

 

BTW I'm NOT suggesting you run subs with your set-up, just curious.

[SOUND PROOF]

 

Last Thursday, on my New year's Eve gig, C# was ringing in the monitors (I wasn't running sound). I had played that particular club hundreds of times spanning over twenty years, and never had that problem. So even if that resonant frequency was inherent to the room and/or system, all the previous techs had no problem dialing it out. The tech in question was new to the room and had changed something somewhere. So... a parametric or graphic equalizer could help with your "woofy" problem but you might be able to solve it by other means. And as noted, just watch that you don't radically change the timbre of any particular instrument or voice, when you start chopping or notching frequencies. Just curious, was your PA fairly decent (mics, speakers, mixer...), and were you running subs? Was the bass miced or using a bridge pick-up? Were you using an electric or acoustic guitar? BTW I'm NOT suggesting you run subs with your set-up, just curious.

 

Actually I kind of skimped my sound out that night usually I run JBL PRX 15'S (mains) and EON's (as my monitors). This night I just brought the EON'S, I won't do that again. I have a taylor expression system in my guitar and the mic I was using was a shure 55. The other guys were running lines straight in to the board. Double bass had a fishman bass blender between him and the board, flute was using some type of mic on his flute not sure what.

[agedhorse]

The Shure 55 may have contributed to your problem. Was it an original or repro?

[dboomer]

 

The stage I work on has a standing wave at ...

 

 

I think you mean to say a "resonance". If it were indeed a standing wave it would come and go anytime you moved your ear in any direction by 1 foot.

[Dogoth]

 

I think you mean to say a "resonance". If it were indeed a standing wave it would come and go anytime you moved your ear in any direction by 1 foot.

 

 

Thanks for the correction. Yes a standing wave varies at different points in the room making nodes of increased and/or decreased amplitude at different positions (in or out of phase reflections (if I'm correct these occur at many different frequencies as well, including & up to 2Khz). This 212hz is a resonance of the S/L & S/R walls (there's another much lesser one somewhere around 80hz between the U/S and back of house walls (although it could be how the FOH guy runs his subs :>)).

[SOUND PROOF]

 

The Shure 55 may have contributed to your problem. Was it an original or repro?

 

I believe its a repro.....

[agedhorse]

 

I believe its a repro.....

 

 

That's better than the original by a big margin too. If it was the original, I would have expected more problems.

[SOUND PROOF]

 

I did a gig around Christmas with a double bass player and a flute and me on guitar and vocals. Me and the bass player ran into a woofy issue, it seemed that when I started to play middle A on my guitar (7th fret 4th string) or (D 5th fret 5th string) and the bass player was playing either one of these notes, we got a woofy resonance that got out of control. We were playing outside in front of a garage about 20 feet from a carport and 30 feet from the corner of the house. I am assuming that this issue had something to do with the mathematics of the architecture and the frequency of the tone. A friend told me that a parametric eq, he said it would solve this problem, I would simply take out the frequency that was in question. If you have any discussion on this please discuss away. I am sure I am just starting to scratch the surface on understanding the math of frequency.

 

 

Ok I did another out door gig with the persistence of yet another woofy issue. I think I need a parametric eq, that tells me where each note lives and the frequency that it occupiSomething that tells me where each note lives and the frequency that it occupies. When I ran sound for another band yesterday I had to completely notch the whole eq to get the sound under control (so there was no woofy feedback on stage). This was the set up. 2 PRX-15'S as my mains, 2 JBL-EON 10'S as my monitors, a Mackie-DFX-12 as my mixer and a dbx 1066 as my compressor. I ran my mains into the dbx then out into the prx15's, below my xlr mains on my mixer I ran my 1/4 inch mains into my monitor speakers which ment I had no compression in my monitors. There were 4 mics on (2 vox, 1 sax, one percussion). The guitar player had his own amp, and the bass player ran directly in. Even when I ran solo singer song writers with just one mic and a line in guitar I ran into the same issue. If any body knows of a good online chart that would list the note frequencies and knows of a GOOD parametric eq please post.

[tlbonehead]

I did a gig around Christmas with a double bass player and a flute and me on guitar and vocals. Me and the bass player ran into a woofy issue, it seemed that when I started to play middle A on my guitar (7th fret 4th string) or (D 5th fret 5th string) and the bass player was playing either one of these notes, we got a woofy resonance that got out of control. We were playing outside in front of a garage about 20 feet from a carport and 30 feet from the corner of the house. I am assuming that this issue had something to do with the mathematics of the architecture and the frequency of the tone. A friend told me that a parametric eq, he said it would solve this problem, I would simply take out the frequency that was in question. If you have any discussion on this please discuss away. I am sure I am just starting to scratch the surface on understanding the math of frequency.

sure, they are very handy. Set some cut and then sweep the frequency area that the problem is in and try and find the center of it. Then you can make the cut as wide or narrow as it needs to be to help the problem.

[tlbonehead]

Ok I did another out door gig with the persistence of yet another woofy issue. I think I need a parametric eq, that tells me where each note lives and the frequency that it occupiSomething that tells me where each note lives and the frequency that it occupies. When I ran sound for another band yesterday I had to completely notch the whole eq to get the sound under control (so there was no woofy feedback on stage). This was the set up. 2 PRX-15'S as my mains, 2 JBL-EON 10'S as my monitors, a Mackie-DFX-12 as my mixer and a dbx 1066 as my compressor. I ran my mains into the dbx then out into the prx15's, below my xlr mains on my mixer I ran my 1/4 inch mains into my monitor speakers which ment I had no compression in my monitors. There were 4 mics on (2 vox, 1 sax, one percussion). The guitar player had his own amp, and the bass player ran directly in. Even when I ran solo singer song writers with just one mic and a line in guitar I ran into the same issue. If any body knows of a good online chart that would list the note frequencies and knows of a GOOD parametric eq please post.

unless you have some poor setup/dialing-in issues outdoors doesn't seem to be a place where you would have major issues. Why would you want comp in your monitors? Lastly, what do you mean by note frequencies? The fundamental of the note? That wouldn't do you much good since tones/sounds are full of overtones, not just the fundamental.

[banddad]

Are you running the compressor on the whole mix? I got a little confused on the description of your setup. I generally use the compressor on only a single input at a time, never on the whole mix. Try simplifying to see it it gets better.

 

As for what occupies what, google "instrument frequencies" for some nice charts of what instruments produce what frequencies.

 

What frequencies are you notching out?

 

I like the Ashly parametric equalizers, but they don't show what frequencies are doing what. There are a couple of 31 band graphic eq's with lights on each channel showing the dominant frequencies. ART HQ-231 is one, Peavey also makes one. Graphics are usually easier to use for live sound, though parametrics can be more precise - with training.

 

Are you using separate eq's for FOH and for stage monitors? Each has their own needs. Often, monitors get eq to notch out feedback frequencies, FOH gets EQ to deal with room eq, and shortcomings in main speakers (though your PRX515's should be fine).

 

Cheers!

[agedhorse]

First, get rid of the comps (any of them) and flatten out all of your eq. Try it again this way first. I suspect that you are creating your own problems here.

[Shaster]

 

This was the set up. 2 PRX-15'S as my mains, 2 JBL-EON 10'S as my monitors, a Mackie-DFX-12 as my mixer and a dbx 1066 as my compressor. I ran my mains into the dbx then out into the prx15's, below my xlr mains on my mixer I ran my 1/4 inch mains into my monitor speakers which ment I had no compression in my monitors. There were 4 mics on (2 vox, 1 sax, one percussion). The guitar player had his own amp, and the bass player ran directly in. Even when I ran solo singer song writers with just one mic and a line in guitar I ran into the same issue. If any body knows of a good online chart that would list the note frequencies and knows of a GOOD parametric eq please post.

 

 

YMMV. I'm starting with that because I want to make that clear.

 

Secondly apologies to any DFX users. I used a DFX years ago, first generation ( for close to a month). I almost had a nervous breakdown. Finally replaced it with a thirty year old Traynor mixer (I needed cheap gear, it was a bad area of town).

 

Second tale.... Six months ago I was in a rehearsal studio and tried for five or ten minutes to get a decent (read pleasant) sound out of a DFX, SM58 and two Yorkville E160P's. I was unsuccesful.

 

Agedhorse and many others will tell you (correctly) that a mixer shouldn't make much difference to your sound, at this lower end of the food chain anyway.

 

I personally feel however that Mackie has done the impossible (maybe more than once). They've made a mixer that sounds bad all on it's own. Is that the root of your problem? No of course not. Is that mixer helping you solve your problem, IMO no it isn't. YMMV.

 

BTW I used to love the Mackie stuff, and still own some of the original goods.

 

Frequency chart. I was going to get cranky and say doesn't anybody read the guide to goobers, but life is short, and do unto others and all that jazz.

 

There's a frequency chart in this forum's guide to goobers. a nice colour chart.

 

Best of luck.

 

Oh yes, +1 for getting rid of the comps. And try agedhorse's EQ suggestion. The DFX has fairly questionable EQ. Flat, and lowering volume could work.