Speaker placement...why does this work???

Discussion in 'Live Sound [BG]' started by tonynoriega, Jan 13, 2013.


  1. tonynoriega

    tonynoriega Supporting Member

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    Many years ago while casually researching sound reinforcement just so I'd know a little more than I did, I learned that speakers should never be placed behind mics for fear of feedback.

    Presently the 3-piece I sometimes play with has me setting up the PA and I'm using 12 JBL's on stands, set up against the back stage wall and facing forward. The band leader had me do this to use the speakers as both mains and monitors since the sound projects right past our ears, and in an attempt to reduce our volume in smaller venues. The method has achieved the desired result and we're all content with the sound and volume (and not having to set up separate monitors is an improvement too).

    It somehow works and I never get feedback! Never! But I don't know why.

    Can anyone tell me how and why this works?!?

    Many thanks....Tony Noriega in Tampa
     
  2. Got2SadowskyNYC

    Got2SadowskyNYC

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    The speakers my be far enough off center that they are in the blind spot of the mic pickup pattern. This is part of the reason side fills don't feed back.

    The mic is pointed up just enough to do the same.

    You're standing in front of the mic blocking it from directly pointing at the speaker.

    You're just lucky.

    Everything is a guess because I've never actually seen how you are set up.

    The Bose L series are designed to do just this and you have to stick the mic right in the speakers grill to get it to feed back.
     
  3. walterw

    walterw Supportive Fender Gold Supporting Member

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    i would guess that you're just running at a lower volume. if you tried to get that setup as loud as you could with the speakers placed "correctly" you'd be in feedback hell.
     
  4. ddnidd1

    ddnidd1 Supporting Member

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    +1
     
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  6. tonynoriega

    tonynoriega Supporting Member

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    The setup is very simple. Picture a 20-foot wide stage with drums in the center and on either side is a 12" speaker on a stand at the back wall flanking the drum kit. That would make the actual speaker spacing about 15 ft from one another I suppose. There are two vocal mics at the front of the stage (which is only about 12 ft deep) and they are definitely in the cone of coverage of the speakers. I get no feedback regardless of whether or not there's a vocalist in front of the mic.

    The master level is set at 12 o'clock or so - in other words at about half volume - and the channel's volume is only at 7 or 8 o'clock. This is in a club with about 100 people. No monitors are used because we're hearing the sound waves as they eminate from the mains behind us. With the drummer's ears being quite a bit lower, we're thinking about adding a side monitor for him.

    Still a mystery and theories and opinions are more than welcome.
     

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