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annoying buzz

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Anonymous
December 22, 2004 1:59:44 PM

Archived from groups: rec.audio.pro (More info?)

our youth group is equipped with a Carvin CDX-something mixer, two JBL
something speakers, two Yamaha something speakers, an Ashly 900w power
amp for the mains and a Carvin EQ amp for the monitors. This is a youth
group band, so things get pretty noisy, i'd say around 85-95db, and for
some reason, we're getting a steady and very annoying buzz sound from
the right speaker stack, and ONLY the right hand speaker stack. It's
very irritating when the music is over and someone is talking. Here's
what i know:
The smaller JBL sits on top of the larger Yamaha, and the right-hand
stack is about 30 feet from the amp.
We run the power cable across the stage alongside the mic and
instrument cables.
The room was just painted, so everything got moved around. The problem
started Before the painters came in, though.
The other sound guy, Kenny, is complaining about a "bad ground lifter."
and plans to buy another one or remove it completely, i'm not sure
which.

I think it's interference from being too close to other cables. Kenny
thinks it's the grounder. Anybody got any bright ideas before he goes
and buys another amp?

Also, the room is poorly equipped acoustically. We get hammered with
echo at around 400hz. and 4000hz. I want to install some acoustic foam
behind the band. Any feedback? no pun intended
All comments are much obliged and appreciated. Thanks.

-dano

More about : annoying buzz

Anonymous
December 22, 2004 10:10:59 PM

Archived from groups: rec.audio.pro (More info?)

LagMastah2000@hotmail.com wrote:
> our youth group is equipped with a Carvin CDX-something mixer, two JBL
> something speakers, two Yamaha something speakers, an Ashly 900w power
> amp for the mains and a Carvin EQ amp for the monitors. This is a youth
> group band, so things get pretty noisy, i'd say around 85-95db, and for
> some reason, we're getting a steady and very annoying buzz sound from
> the right speaker stack, and ONLY the right hand speaker stack. It's
> very irritating when the music is over and someone is talking. Here's
> what i know:
> The smaller JBL sits on top of the larger Yamaha, and the right-hand
> stack is about 30 feet from the amp.
> We run the power cable across the stage alongside the mic and
> instrument cables.
> The room was just painted, so everything got moved around. The problem
> started Before the painters came in, though.
> The other sound guy, Kenny, is complaining about a "bad ground lifter."
> and plans to buy another one or remove it completely, i'm not sure
> which.
>
> I think it's interference from being too close to other cables. Kenny
> thinks it's the grounder. Anybody got any bright ideas before he goes
> and buys another amp?
>
> Also, the room is poorly equipped acoustically. We get hammered with
> echo at around 400hz. and 4000hz. I want to install some acoustic foam
> behind the band. Any feedback? no pun intended
> All comments are much obliged and appreciated. Thanks.
>
> -dano
>


All i can say is I doubt your "sound guy" has a clue
rushing to conclude the amp is at fault without proper troubleshoot is a
way to piss away lots of money
I would suspect a cable has failed
start at the speakers
unplugged sitting all alone do the buzz(of course not but I am taking
this to extremes)
now put a cable on one speaker(but not to the amp) still not buzzing
good so far
now connect it to the amp(unplugged) still no buzz
great we are about 1/4 of the way done

plug the amp in and turn it on(no mixer attached) is it buzzing?
if so you only have 4 things to check again
speaker
wire
amp
ac power

if not add wire that eventually will go to mixer , work backwards until
you can solidly determine a point where the buzz is introduced

check these by substituting know buzz free units

check the ac with a VOM look for voltage between neutral and ground

I am sure with a few clicks you can google up
"basic sound system troubleshooting"
Please do so before buying another amp
George
Anonymous
December 22, 2004 10:13:20 PM

Archived from groups: rec.audio.pro (More info?)

George Gleason wrote:
> LagMastah2000@hotmail.com wrote:
>
>> our youth group is equipped with a Carvin CDX-something mixer, two JBL
>> something speakers, two Yamaha something speakers, an Ashly 900w power
>> amp for the mains and a Carvin EQ amp for the monitors. This is a youth
>> group band, so things get pretty noisy, i'd say around 85-95db, and for
>> some reason, we're getting a steady and very annoying buzz sound from
>> the right speaker stack, and ONLY the right hand speaker stack. It's
>> very irritating when the music is over and someone is talking. Here's
>> what i know:
>> The smaller JBL sits on top of the larger Yamaha, and the right-hand
>> stack is about 30 feet from the amp.
>> We run the power cable across the stage alongside the mic and
>> instrument cables.
>> The room was just painted, so everything got moved around. The problem
>> started Before the painters came in, though.
>> The other sound guy, Kenny, is complaining about a "bad ground lifter."
>> and plans to buy another one or remove it completely, i'm not sure
>> which.
>>
>> I think it's interference from being too close to other cables. Kenny
>> thinks it's the grounder. Anybody got any bright ideas before he goes
>> and buys another amp?
>>
>> Also, the room is poorly equipped acoustically. We get hammered with
>> echo at around 400hz. and 4000hz. I want to install some acoustic foam
>> behind the band. Any feedback? no pun intended
>> All comments are much obliged and appreciated. Thanks.
>>
>> -dano
>>
>
Also look for noise sources
look for lighting dimmers not fully on or off
or rheostat type fan/heater controls not all the way on or off
George
Related resources
Anonymous
December 22, 2004 10:36:58 PM

Archived from groups: rec.audio.pro (More info?)

<LagMastah2000@hotmail.com> wrote in message
news:1103741984.046715.298660@c13g2000cwb.googlegroups.com...
> our youth group is equipped with a Carvin CDX-something mixer, two JBL
> something speakers, two Yamaha something speakers, an Ashly 900w power
> amp for the mains and a Carvin EQ amp for the monitors. This is a youth
> group band, so things get pretty noisy, i'd say around 85-95db, and for
> some reason, we're getting a steady and very annoying buzz sound from
> the right speaker stack, and ONLY the right hand speaker stack. It's
> very irritating when the music is over and someone is talking. Here's
> what i know:
> The smaller JBL sits on top of the larger Yamaha, and the right-hand
> stack is about 30 feet from the amp.
> We run the power cable across the stage alongside the mic and
> instrument cables.
[snip]
> I think it's interference from being too close to other cables. Kenny
> thinks it's the grounder. Anybody got any bright ideas before he goes
> and buys another amp?

First, do some detective work. I assume each stack is plugged into one
channel of the Ashly? Okay, turn off the amp and swap them -- plug the cable
that was plugged into the Ashly's L channel into the R channel, and vice
versa. Turn on. Is the buzz now coming from the left stack instead of the
right? Good; the problem's in the amp or something upstream from it. (If the
buzz stayed in the right stack, you have an unusual situation. Move the
power cable and see if that fixes it.)

Turn it off again, and put the speaker cables back into their regular Ashly
channels. Now swap the Ashly's inputs, right and left. Turn back on. Is the
buzz still in the right stack? Then the problem's in the amp itself; get it
fixed. Did it jump to the left stack? Then the problem's upstream. Turn off,
and swap the *other* end of the cable from the mixer to the Ashly. Turn on.
Where's the buzz? If it's back in the right stack, the problem's almost
certainly in the mixer, and you need to get it fixed. If it's still in the
left stack, it's the cable that's now in the left stack. Replace it.

By the way, you *should* be able to run this system without ground lifters.
Is the mixer plugged into the same power strip as the power amps? It should
be; run an extension cord if necessary.

Peace,
Paul
Anonymous
December 23, 2004 4:01:53 AM

Archived from groups: rec.audio.pro (More info?)

> I think it's interference from being too close to other cables. Kenny
> thinks it's the grounder. Anybody got any bright ideas before he goes
> and buys another amp?

Great troubleshooting advice already. Always suspect a cable or where the
cable plugs in first. If then, it really looks like an amp, just borrow or
rent another to see if that is the problem-if so, then talk about buying
another, or get the offending unit repaired.
>
> Also, the room is poorly equipped acoustically. We get hammered with
> echo at around 400hz. and 4000hz. I want to install some acoustic foam
> behind the band. Any feedback? no pun intended
At 400 and 4k possibly indicates that 400 is really the main problem
frequency. What's wrong with just using equalizers at this point? I'll
agree, if you can tame the problem acoustically you'd be better off. You
might calm things down with acoustic foam, but it better be the thicker
stuff, say 2" or better. Perhaps some combination absorbing/diffusing
material such as this:
http://www.auralex.com/acoustic_foam_trutrap/acoustic_f...
http://www.auralex.com/acoustic_studiofoam_3w/acoustic_...
http://www.auralex.com/acoustic_foam_sunburst/acoustic_...
Anyone who visited the Servodrive/SPL booth at NSCA last year saw some gobos
I made using the Sunburst product. This type of set up may give you enough
help on stage. I made a tri-fold set up with a 24" middle section using one
gender, and two outside wings 12" each with one piece of the opposite gender
foam. The flexibility to optimize their position on stage could be very
useful.

Best regards,

John
Anonymous
December 23, 2004 7:41:08 AM

Archived from groups: rec.audio.pro (More info?)

When I was in college, some friends of mine got hold of some stuff that was,
apparantly, a batch of Extascy that went bad somewhere along the
"manufacturing" process. The "designer" call it "Mad Dogs From Hell" because
it was supposedly like having mad dogs running around in your head. They took
it anyway. Now THAT sounds like an annoying buzz!

-jeff
Anonymous
December 26, 2004 2:31:24 PM

Archived from groups: rec.audio.pro (More info?)

John Halliburton wrote:
> > I think it's interference from being too close to other cables.
Kenny
> > thinks it's the grounder. Anybody got any bright ideas before he
goes
> > and buys another amp?
>
> Great troubleshooting advice already. Always suspect a cable or
where the
> cable plugs in first. If then, it really looks like an amp, just
borrow or
> rent another to see if that is the problem-if so, then talk about
buying
> another, or get the offending unit repaired.
> >
> > Also, the room is poorly equipped acoustically. We get hammered
with
> > echo at around 400hz. and 4000hz. I want to install some acoustic
foam
> > behind the band. Any feedback? no pun intended
> At 400 and 4k possibly indicates that 400 is really the main problem
> frequency. What's wrong with just using equalizers at this point?
I'll
> agree, if you can tame the problem acoustically you'd be better off.
You
> might calm things down with acoustic foam, but it better be the
thicker
> stuff, say 2" or better. Perhaps some combination
absorbing/diffusing
> material such as this:
>
http://www.auralex.com/acoustic_foam_trutrap/acoustic_f...
>
http://www.auralex.com/acoustic_studiofoam_3w/acoustic_...
>
http://www.auralex.com/acoustic_foam_sunburst/acoustic_...
> Anyone who visited the Servodrive/SPL booth at NSCA last year saw
some gobos
> I made using the Sunburst product. This type of set up may give you
enough
> help on stage. I made a tri-fold set up with a 24" middle section
using one
> gender, and two outside wings 12" each with one piece of the opposite
gender
> foam. The flexibility to optimize their position on stage could be
very
> useful.
>
> Best regards,
>
> John
!