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Need Advise on Feedback / Feedback Eliminators



 
 
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  #1  
Old June 22nd 04, 01:08 AM
Marshall
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Default Need Advise on Feedback / Feedback Eliminators

I am having a very frustating time getting the volume we disire out of
my sound system w/o excessive feedback. I play in a bluegrass band (
www.whitepinehollow.com ) and attemtping to get a clean, amplified
acoustic sound working a single condenser mike. Our system is: AKG C
3000 B mike, sometimes a AKG C 1000 on the acoustic bass at very low
gain, Mackie 1202 board, JBL EON G2 Powered speakers. It seem like
I'm in a tug - of - war between cutting gain (loosing the mike power
we need) and increasing volume. I've had tons of advise from "ditch
the powered speakers - they're for outdoors only", to "ditch the
condenser mikes, they'll only feed". I am tempted to try a feedback
eliminator but have been told they take out too much tone?

Any and all suggestions are welcomed!

Thanks,
Marshall
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  #2  
Old June 22nd 04, 02:01 AM
philicorda
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On Mon, 21 Jun 2004 17:08:40 -0700, Marshall wrote:

> I am having a very frustating time getting the volume we disire out of
> my sound system w/o excessive feedback. I play in a bluegrass band (
> www.whitepinehollow.com ) and attemtping to get a
> clean, amplified acoustic sound working a single condenser mike. Our
> system is: AKG C 3000 B mike, sometimes a AKG C 1000 on the acoustic
> bass at very low gain, Mackie 1202 board, JBL EON G2 Powered speakers.
> It seem like I'm in a tug - of - war between cutting gain (loosing the
> mike power we need) and increasing volume. I've had tons of advise from
> "ditch the powered speakers - they're for outdoors only", to "ditch the
> condenser mikes, they'll only feed". I am tempted to try a feedback
> eliminator but have been told they take out too much tone?
>
> Any and all suggestions are welcomed!


I'm afraid the only way to get volume is a few more mics, and closer
micing. Perhaps pickups on some instruments, combined with mics on those
that really need mics.

A feedback eliminator will probably get it a bit louder, but if you are on
the edge already it wont do much good. They are great for when a mic is
hand held, and you never know where it's going to be pointed next (usually
straight into a monitor), but not so good when they are hunting all
the time. The more the feedback eliminator is working, the weirder it'l
sound.

A big multiband graphic eq across the mains may help out if you really
don't want to change how you are micing, you can pull down the feedback
frequencies quite a lot before the sound changes too much.

Else, you could put the speakers a long way away, perhaps even at the back
of the hall facing towards you. I've never tried that, but it might work
ok!

>
> Thanks,
> Marshall


  #3  
Old June 22nd 04, 02:11 AM
Arny Krueger
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"Marshall" > wrote in message
m
> I am having a very frustating time getting the volume we desire out of
> my sound system w/o excessive feedback. I play in a bluegrass band (
> www.whitepinehollow.com ) and attempting to get a clean, amplified
> acoustic sound working a single condenser mike. Our system is: AKG C
> 3000 B mike, sometimes a AKG C 1000 on the acoustic bass at very low
> gain, Mackie 1202 board, JBL EON G2 Powered speakers. It seem like
> I'm in a tug - of - war between cutting gain (loosing the mike power
> we need) and increasing volume. I've had tons of advise from "ditch
> the powered speakers - they're for outdoors only", to "ditch the
> condenser mikes, they'll only feed". I am tempted to try a feedback
> eliminator but have been told they take out too much tone?
>
> Any and all suggestions are welcomed!


Check out these potentially helpful documents:

http://www.carvin.com/doctorsound/drsound03.php

http://www.shure.com/support/technotes/app-eq.html

http://www.prosoundweb.com/install/tfw/feedback.php

I think you'll find that they don't relate very strongly to any of the
issues you've raised. I've got a few concerns about a few items in these
documents, based on my own experiences. But, I think they will get you from
where you are, to where you need to be for additional discussion of the
matter.


  #4  
Old June 22nd 04, 02:36 AM
Hannibul Artese
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In article > ,
(Marshall) wrote:

> I am having a very frustating time getting the volume we disire out of
> my sound system w/o excessive feedback. I play in a bluegrass band (
>
www.whitepinehollow.com ) and attemtping to get a clean, amplified
> acoustic sound working a single condenser mike. Our system is: AKG C
> 3000 B mike, sometimes a AKG C 1000 on the acoustic bass at very low
> gain, Mackie 1202 board, JBL EON G2 Powered speakers. It seem like
> I'm in a tug - of - war between cutting gain (loosing the mike power
> we need) and increasing volume. I've had tons of advise from "ditch
> the powered speakers - they're for outdoors only", to "ditch the
> condenser mikes, they'll only feed". I am tempted to try a feedback
> eliminator but have been told they take out too much tone?



The problem is that acoustic gain is inversely proportional to the
distance between the microphone and sources. If you want to work further
from the microphone, then you need to move the speaker further from the
mic, or the audience closer to the speaker. With only a pair of powered
speakers, you probably can't do much about the relative distances between
speaker and mic, or speaker and audience.

So, if you want more gain, you need to close the distance between the
mic and the instruments.

I'd consider pickups or close micing on instruments as the next step.

And yes, the feedback eliminator is a bandaid. Avoid it if at all
possible.
  #5  
Old June 22nd 04, 03:54 AM
Tim Perry
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"Arny Krueger" > wrote in message
...
> "Marshall" > wrote in message
> m
> > I am having a very frustating time getting the volume we desire out of
> > my sound system w/o excessive feedback. I play in a bluegrass band (
> > www.whitepinehollow.com ) and attempting to get a clean, amplified
> > acoustic sound working a single condenser mike. Our system is: AKG C
> > 3000 B mike, sometimes a AKG C 1000 on the acoustic bass at very low
> > gain, Mackie 1202 board, JBL EON G2 Powered speakers. It seem like
> > I'm in a tug - of - war between cutting gain (loosing the mike power
> > we need) and increasing volume. I've had tons of advise from "ditch
> > the powered speakers - they're for outdoors only", to "ditch the
> > condenser mikes, they'll only feed". I am tempted to try a feedback
> > eliminator but have been told they take out too much tone?
> >
> > Any and all suggestions are welcomed!

>


first question: do you have someone running the sound for the entire show
or do you self mix from the stage?

second question: are the times that you have the worst problems when
available space dictates placing the speakers close to the performers?

third question: do you use a 1/3 octave graphic EQ on the mains?


FBX units work by activating a narrowband notch filter(s) of varying depths.
for a more detailed explanation visit http://www.sabine.com/ .

like any tool they have their pluses and minuses. i find that when a rock or
blues band demands really loud stage volume it gives me an extra few dB of
headroom before feedback.
using them on long, brain numbing conferences a sudden squeal (someone
cupping a mic or some goofy thing) is squelched before i can get my hand to
the board.


just using the info that you have posted my best guestimate would be that
you need to address your stage setup and techniques. you need to create a
situation where the microphone hears the instruments and not the sound from
the speakers. if you cannot achieve this you will need to close mic the
instruments and vocals.






  #6  
Old June 22nd 04, 06:19 PM
Raymond
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Marshall wrote
>Our
>> system is: AKG C 3000 B mike, sometimes a AKG C 1000 on the acoustic
>> bass at very low gain, Mackie 1202 board, JBL EON G2 Powered speakers.


Not the best microphones in the world you have there, those JBL EON's should
work fine. If your Mackie 1202 board has a sweep for the midrange try sweeping
to about 2300Htz and take out as much as you need. There are lot's of other bad
frequency's but that is one that will feedback quite a bit.
  #7  
Old June 22nd 04, 06:55 PM
Dan York
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Default

Hello!

I've played in a few bluegrass bands over the years and they are usually
quite interesting bands to setup mic's and p.a.'s for. Problems range
from mic-shy performers ( some fear about electrical-powered things ) to
trying to fit 4 or 5 people around one mic. Probably some of the best
sounding gigs were the ones where everyone had their own instrument mic
which minimized shuffling around on stage, but lacked that certain
down-home appeal of everyone close together for the vocal harmonies
around one mic. We also had our own vocal mics, too, since we usually
sang 3 or 4 part harmonies. This setup worked well on large outdoor
stages or settings. A big difference can be made by the individuals
stepping back slightly from the mic when they aren't taking a
break/solo....and this requires a little practice for most bluegrass
musicians. Also, monitors for the vocals really pay-off if you can
incorporate them.
I agree with the others about close mic'ing everything in the case of
getting some volume out, but I realize what you are trying to do with
just two mic's...and it is really difficult to pull off. Maybe just
make sure the pa main speakers are in front of the mic's a little, and
if you are all closeup around the A3000 mic you shouldn't need a monitor
then, Make sure your bass player is somewhat centerstage behind the
performers if possible. When you boost your volume level and things
start to feedback, either eq that squeel or howl out with a graphic
eq, and or turn down a wee bit at that point. One other thing...you
may want to make sure the mic's are somewhat isolated from the stage.
That foot tapping and stomping can telegraph right into the pa and sound
pretty bad. Same with the bass player. We used to use foam wrapped
around the mic and wedge it under the tailpiece, pointed up to the
bridge, and that would keep a lot of the mechanical/wood noise out of
the mic...and didn't sound half bad, either. We used a Shure 58 for
that, and I'm not too sure you'd want to do that to your AKG 1000. But
some sort of isolated mount could help.
I hope this helps some, and let me know if I can be of further
assistance.

Sincerely,
Dan


  #8  
Old June 23rd 04, 01:35 AM
Tim Padrick
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I prefer to have a 1/3 octave AND a feedback gadget (Sabine 3102 in my
case). Let the Sabine take care of the feedback that comes up as you raise
the gain. When you are done fiddling, lock the filters (I don't run any
floating filters). Then use the 1/3 octave for those freqs that are "loose"
but not feeding back. (When you ring out with the FBX, turn the amp inputs
down and run the board hot, so you are hitting the FBX with plenty of signal
so the detector will work faster. When done, then turn the amps back up.)


"Dan York" > wrote in message
...
> Hello!
>
> I've played in a few bluegrass bands over the years and they are usually
> quite interesting bands to setup mic's and p.a.'s for. Problems range
> from mic-shy performers ( some fear about electrical-powered things ) to
> trying to fit 4 or 5 people around one mic. Probably some of the best
> sounding gigs were the ones where everyone had their own instrument mic
> which minimized shuffling around on stage, but lacked that certain
> down-home appeal of everyone close together for the vocal harmonies
> around one mic. We also had our own vocal mics, too, since we usually
> sang 3 or 4 part harmonies. This setup worked well on large outdoor
> stages or settings. A big difference can be made by the individuals
> stepping back slightly from the mic when they aren't taking a
> break/solo....and this requires a little practice for most bluegrass
> musicians. Also, monitors for the vocals really pay-off if you can
> incorporate them.
> I agree with the others about close mic'ing everything in the case of
> getting some volume out, but I realize what you are trying to do with
> just two mic's...and it is really difficult to pull off. Maybe just
> make sure the pa main speakers are in front of the mic's a little, and
> if you are all closeup around the A3000 mic you shouldn't need a monitor
> then, Make sure your bass player is somewhat centerstage behind the
> performers if possible. When you boost your volume level and things
> start to feedback, either eq that squeel or howl out with a graphic
> eq, and or turn down a wee bit at that point. One other thing...you
> may want to make sure the mic's are somewhat isolated from the stage.
> That foot tapping and stomping can telegraph right into the pa and sound
> pretty bad. Same with the bass player. We used to use foam wrapped
> around the mic and wedge it under the tailpiece, pointed up to the
> bridge, and that would keep a lot of the mechanical/wood noise out of
> the mic...and didn't sound half bad, either. We used a Shure 58 for
> that, and I'm not too sure you'd want to do that to your AKG 1000. But
> some sort of isolated mount could help.
> I hope this helps some, and let me know if I can be of further
> assistance.
>
> Sincerely,
> Dan
>
>



  #9  
Old June 23rd 04, 02:12 PM
Richard Kuschel
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Default

>
>Else, you could put the speakers a long way away, perhaps even at the back
>of the hall facing towards you. I've never tried that, but it might work
>ok!


No! that won't work. The sound will be so disjointed that you will have timing
issues.
Richard H. Kuschel
"I canna change the law of physics."-----Scotty
  #10  
Old June 23rd 04, 02:12 PM
Richard Kuschel
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>
>Else, you could put the speakers a long way away, perhaps even at the back
>of the hall facing towards you. I've never tried that, but it might work
>ok!


No! that won't work. The sound will be so disjointed that you will have timing
issues.
Richard H. Kuschel
"I canna change the law of physics."-----Scotty
 




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