Phase cancellation via Acoustic Guitar

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halftank
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Joined: Thu Dec 05, 2013 5:44 pm

Phase cancellation via Acoustic Guitar

#1 Post by halftank »

Got a dum question, my lead singer plays acoustic rhythm guitar with a pre amp, we put the acoustic through the mixer and out to the mains and monitors. He sets his on board eq so that there is a lot of bottom end in his acoustic. Just wondering if so much bottom end coming through the acoustic stage monitor is causing phase cancellation with my bass? Some song my bass goes muddy, especially the songs that the rhythm is bassy in! I am running a jack light with a delta 2512. I have tried bringing up my mids but then it get thin and string noise is more noticeable.

Sorry if I am of my rocker here. just can't figure out what I am doing wrong.

Wayne

Bruce Weldy
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Re: Phase cancellation via Acoustic Guitar

#2 Post by Bruce Weldy »

You aren't doing anything wrong....well probably.

He definitely should NOT add low end to an acoustic. You should engage the hi pass filter on the mixer channel to help keep the low end out. Anytime you have low end added to guitars, they will be competing with the frequencies that the bass should have all for its own. It can certainly cause you to have a hard time finding the bass in the mix. And it's not just on stage, it's happening out front too.

Now, that said - do you have your bass cab up against the back wall? If not, you could be getting cancellations at certain frequencies by being out from the wall.

Put your cab against the wall and remind the acoustic player that there is a bass in the band and he shouldn't be trying to handle that end of the frequency spectrum too. Not only does it muddy up your tone, but it muddies up his too.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Bill Fitzmaurice
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Re: Phase cancellation via Acoustic Guitar

#3 Post by Bill Fitzmaurice »

Bruce Weldy wrote:remind the acoustic player that there is a bass in the band and he shouldn't be trying to handle that end of the frequency spectrum too. Not only does it muddy up your tone, but it muddies up his too.
+1.

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Tom Smit
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Re: Phase cancellation via Acoustic Guitar

#4 Post by Tom Smit »

halftank wrote:Got a dum question<snip>......
Wayne
I had a similar situation with a baby grand piano that was going through the monitors whilst I was playing bass. My cabs were against the wall. I asked the board engineer to please hi-pass the monitors at 100 hz.
TomS

Bruce Weldy
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Re: Phase cancellation via Acoustic Guitar

#5 Post by Bruce Weldy »

Tom Smit wrote:
halftank wrote:Got a dum question<snip>......
Wayne
I had a similar situation with a baby grand piano that was going through the monitors whilst I was playing bass. My cabs were against the wall. I asked the board engineer to please hi-pass the monitors at 100 hz.
Which would solve your monitor problem......but not out front. That's something the FOH engineer should have fixed before the gig ever started.

It's become almost second nature for me now to set a high pass on each channel before we even start a sound check. I have a variable filter on my board, so I pass the cymbals and hat at around 4-500 just to take any stand rumble out. Even the floor tom get high-passed if there is too much low end in it. Our systems today have the ability to create so much bottom that there are all kind of things leaking in down there that need to be kept out.

While I don't use aux fed subs, I do pretty much keep them handling only bass and kick. They still get some content from guitars, keys, and vocals - but it's been rolled off pretty good before it gets there.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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dswpro
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Re: Phase cancellation via Acoustic Guitar

#6 Post by dswpro »

+1 on HPF on inputs. I would rather have a variable HPF on every channel than a three band EQ.
Fortunately I use an X32 and have a HPF and parametric.

It is common to portion low end out to the bass + kick and remove too much low end from guitars, keys and other instruments. One of the problem spots in small rooms is the low end on acoustic guitars. Not so much with monitors for me as with feeding back in the mains. I recommend Planet Waves Screeching Halt Acoustic Soundhole Cover, a rubber disc that sits in the sound hole and keeps the acoustic from feeding back on the low end so much. Five dollars on Amazon and worth every penny.

halftank
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Re: Phase cancellation via Acoustic Guitar

#7 Post by halftank »

Hello fellow bassists, So we had the acoustic taken out of the low end and placed my cab behind me closer to the back wall. Must say big difference. I even had to dial it down a few notches. The bass is more fuller and defined.

Thanks

Wayne

Bruce Weldy
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Re: Phase cancellation via Acoustic Guitar

#8 Post by Bruce Weldy »

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6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Tom Smit
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Location: Sarnia, Ont. Canada

Re: Phase cancellation via Acoustic Guitar

#9 Post by Tom Smit »

:hyper: :clap:
TomS

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