Author Topic: Advice needed on PA EQ & Feedback  (Read 291 times)

David Houck

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Advice needed on PA EQ & Feedback
« on: August 29, 2017, 03:26:52 PM »
Here's my situation.  I provide sound and recording for a question and answer event a couple of times a month.  The primary person speaking is seated and I have a boom mic on her.  There are maybe 18 for so folks seated in the audience, and a mic is passed around to them.  The room is not much larger than comfortably accommodating that number of folks.  Currently I'm using a simple powered head with no individual tone controls for the channels and only bass, mid, treble overall.

For our regular room, I am able to get by with this setup okay.  However, we were recently in a different location, a larger more "live" room.  I could not get the "ringing" out of the system satisfactorily.  As the mic was passed around, I was moving the direction the speaker was pointed to try to eliminate the ringing, while EQing as I went.  In both situations, I aim the speaker at walls so that it's not directly in the line of the mic.

I have a bunch of old PA stuff, and I'm considering putting my old 16 track analog mixing board back in its rack, get a light weight power amp, and something like this ...

https://www.sweetwater.com/store/detail/HQ231

I am not a sound person, and at my age and with my bad hearing, I won't be.  I don't get compensated for this, but I do want to try to provide good quality sound for this group.  I also want to keep setup and teardown as simple, quick, lightweight, and easy as possible.

I've been considering powered heads, feedback elimanators, etc, but I'm leaning toward the ART EQ linked above and my old board with a new lightweight power amp.  The reviews of the ART appear to be good, and I think it will do want I want.  It's more money than I want to spend, but at the moment there's a used one on Reverb and Ebay that I'm ready to move on.

What do you think?

[added]  The mics are currently both 58's.  I tried a 57 for the audience mic, but its hard to get people to hold the mic correctly, and the 58 just works better in that situation.
« Last Edit: August 29, 2017, 03:32:28 PM by David Houck »

the_home

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Re: Advice needed on PA EQ & Feedback
« Reply #1 on: August 29, 2017, 04:53:00 PM »
In a 'live' room, pointing the speakers at the wall probably doesn't help matters, as you'll have to deal with the reflection. Also, using SM58s rather that SM57 may be leading people to think 'side address' on the microphone works fine. Under the ball, a 58 is the same element as a 57. The look of the SM57 may make people actually use it more appropriately. Lastly, if your 'simple powered head' has an effects loop you can put the eq in the loop and forego the expense of new gear. Unless, you kinda don't mind 'needing' to get some new gear...
Essence 5; Spoiler 5(BigRedBass); Essence 4; Spoiler Exploiter 4; what's next?

David Houck

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Re: Advice needed on PA EQ & Feedback
« Reply #2 on: August 29, 2017, 05:03:34 PM »
Yes, I've been considering trying the 57 again; but these aren't singers, they're just ordinary people focused on what they're saying.  And even with reminders, some tend to let their arms drop while their talking and they forget they even have a mic in their hand.

And yes, that's a good idea about trying the ART in the effects loop of the powered mixer I'm currently using.

Thanks!
« Last Edit: August 29, 2017, 05:05:19 PM by David Houck »

cozmik_cowboy

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Re: Advice needed on PA EQ & Feedback
« Reply #3 on: August 29, 2017, 05:43:55 PM »
1) The most important piece of any system (besides the operator) is a graphic EQ.  This the soundman's basic tool; everything else is frosting.
In your case, a parametric might serve in a pinch; narrow notch, large cut, sweep the freqs until you find the nasty.

2) Having built the system for the local UU church & trained it's operators (and purchased mics of the basic type I was used to, unfortunately- cardioid handhelds), I can say that the biggest challenge going from singers to speakers was television; everybody thinks all mics work like the ones Ed used to carry into the seats so people could ask johnny stuff.  End-address is a tough concept to sell to people thus conditioned.
"Don't take life so serious; it ain't no ways permanent"

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David Houck

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Re: Advice needed on PA EQ & Feedback
« Reply #4 on: August 29, 2017, 05:55:38 PM »
... sweep the freqs until you find the nasty.

Supposedly, this ART unit indicates which slider to pull down when feedback occurs.  Similarly, when setting up, it should indicate which sliders show frequencies that will be prone to ringing and feeding back, so they can be pulled down ahead of time.  Some of the reviewers wrote that it did indeed do this.

This is what I'm wondering, if it really does this effectively.  Again, I'm not a pro sound person, and trying to figure out which slider to pull down on a traditional graphic EQ is not something I want to be doing while these folks are having their focused discussions.  If the ART can quickly show me which slider to pull down and that takes care of the problem, that's what I would like to have happen.

elwoodblue

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Re: Advice needed on PA EQ & Feedback
« Reply #5 on: August 29, 2017, 08:31:12 PM »
 
In my short stint doing local sound, I was surprised at how well the Sennheiser 835's(and 935's) worked at rejecting feedback. Nice sound too.
 


David Houck

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Re: Advice needed on PA EQ & Feedback
« Reply #6 on: August 29, 2017, 08:42:33 PM »
Hmmm ... I hadn't considered new mics.

elwoodblue

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Re: Advice needed on PA EQ & Feedback
« Reply #7 on: August 29, 2017, 09:03:24 PM »
A new mic might be 'frosting' as Peter points out.
  The Sennheisers really did solve some live problems, even with a floor monitor at the front of the stage.
 Those little jobs can be challenging with all the variables.


That ART unit does look neat.




lbpesq

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Re: Advice needed on PA EQ & Feedback
« Reply #8 on: August 29, 2017, 10:34:58 PM »
Moder Dave, I have a few Sabine FBX solo individual mic feedback eliminators that I don't use or anticipate using in the foreseeable future.  They're not worth a lot, but they do the job.  If you think this could help, it is yours for the price of shipping.  Let me know if you are interested and I'll dig them out and let you know the specific model.

Bill, tgo

cozmik_cowboy

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Re: Advice needed on PA EQ & Feedback
« Reply #9 on: August 30, 2017, 04:11:08 AM »
I didn't read the info on the ART - built-in RTA?  Go for it!

Peter
"Don't take life so serious; it ain't no ways permanent"

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David Houck

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Re: Advice needed on PA EQ & Feedback
« Reply #10 on: August 30, 2017, 06:16:28 AM »
Peter, it does not have built-in RTA.  Apparently, when setting up, you raise the master gains until it starts to feedback; an LED will light on the fader representing the frequency band within which the feedback is occurring.

Bill, thanks for the kind offer!  I've glanced at those this morning.  I'm leaning towards the used ART unit, but if I'm still unsure later on, I may check back with you on the model numbers.

Elwood, I found some rather reasonable used prices for those mics; so that might be a consideration at some point.

keith_h

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Re: Advice needed on PA EQ & Feedback
« Reply #11 on: August 30, 2017, 08:29:14 AM »
For spoken word in the type of places you are dealing with I wouldn't bother with RTA. I'm not even sure I would worry about built-in feedback detection. I would just start with the EQ set to flat and walk the mic around the room to ring out the system. It shouldn't take much cut to eliminate the frequencies causing the feedback with just basic trial and error. I think you might even be able to get by with a 15-band unit as we aren't talking about a situation that needs hi-fidelity.  One thing to keep in mind is the way people hold and talk into the mic can affect feedback so be sure to use/hold it in different ways to account for this.

David Houck

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Re: Advice needed on PA EQ & Feedback
« Reply #12 on: August 30, 2017, 08:42:09 AM »
Thanks Keith; it's the "trial and error" I'm concerned about.  People arrive early while I'm still setting up, and my preference is to disturb them as little as possible.  That's why I find the built-in feedback detection so appealing - if it works as suggested.

I'll try the 57 for the audience mic again at the next meeting, and have someone give a reminder and mic holding demo before the session starts.

murray

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Re: Advice needed on PA EQ & Feedback
« Reply #13 on: August 30, 2017, 08:48:01 AM »
All above points are valid.  I do the PA (mine) for one of the bands (folk) I play for and the perpetual problems are:-
1)   Getting them to do a sound check.
2)   If they do, then getting them to use the mic as they would when performing.  They whisper on the sound check then bellow on performance.
3)   Getting them to understand that the mic is a handheld bit of kit that if brought nearer to the mouth acts as your own volume control.  If they hold it at waist height then it is not surprising that nobody can hear.
4)   Finally, I play bass at the the same time and they look round to ask for adjustments whilst we are performing.  This involves multiple acrobatics and a lot of use of one hand on open strings.

That said, it is worth it when we get it right.
Glynn

David Houck

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Re: Advice needed on PA EQ & Feedback
« Reply #14 on: August 30, 2017, 08:59:24 AM »
Nice comment, Glynn; made me smile.

Just now purchased the used ART unit off Reverb.