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Auction Sound in Gymnasium

Discussion in 'Sound, Music, and Intercom' started by videogreg, May 8, 2008.

  1. videogreg

    videogreg Member

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    I found myself in an acoustical nightmare recently, and would love any suggestions. Picture a large high-school gymnasium, filled with 40 or so large round tables for a formal dinner, in the center a large elevated runway on which a live auction is held. Now add 300 or so adults (who have been drinking for a couple hours at this point) and have no interest in listening to the auction. They continue to talk, as the sound level of the auction is increased in an attempt to allow the 3 or 4 people in the room who do want to hear the auctioneer to hear, the crowd just gets louder. Ultimately sound is bouncing everywhere in a disastrous cacophony and the complaints begin to roll in that "no body can hear the auctioneer". UUGGGHHH!

    While nobody was satisfied, and everyone complained, now I'm hearing that it was "better than last year." and "What can we do to make this work next year?"

    IMHO, other than getting the crowd to shut up, this is an acoustical impossibility .. any suggestions?
  2. Dustincoc

    Dustincoc Active Member

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    Madrid, New York
    Maybe throw up some acoustical panels to soak up the excess sound?
  3. soundop

    soundop Active Member

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    acoustic shields
  4. avkid

    avkid Not a New User Fight Leukemia

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    Stageline Operator/Staging Supervisor
    Howell, NJ
    Get the horns up way over the heads of the crowd.
    Or just hire someone with a whole of bunch of PA and some towers.
  5. museav

    museav CBMod CB Mods Departed Member

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    Acoustical, audio and audiovisual consultant
    Marietta, GA
    We could likely be of more help if you could tell us more about the situation. What were you using for the system? Where were the speakers? Is it just the auctioneer or do you also have to deal with music? How big is the room and what are the room finishes? Does the room have any acoustical treatments? Were there curtains or anything used to help make the room look nicer or to create a backdrop?
    Last edited: May 11, 2008
  6. Peter

    Peter Well-Known Member

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    MA, USA
    Ya, more info would certainly be useful.

    If you have a buch of speakers that you can spread out across the room, so each of the fires at a lower volume that could be ideal. if this is not an option, as was mentioned, getting the speakers above people's heads is a good idea. Taking this a step farther and getting the speakers high above people and shooting them down at them may help with some of the reflections depending on how the tables are setup / how dense the people are.

    Another thing to look at is your EQ. If you're lucky, you can push up some of the vocal clairty frequencies (1k-5k depending on the person) without introducing feedback or even more echos.

    Otherwise there is today's answer to everything 'just hang a line array and tune it to a very tight pattern!' ::sarcastic::
  7. videogreg

    videogreg Member

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    Thanks for everyone's advice.

    I'll have to get back to the forum on the dimensions of the room.
    The walls are concrete block, floor is hardwood. One "wall" is really a set of pull out hard plastic bleachers with a gallery hallway above it. Ceiling is untreated (no sound treatment) steel on steel. They do not hang any drape, just plastic decorative around the room. So 5 of the 6 surfaces are "hard" isn't exactly absorbent. If you picture a rectangle, the stage/runway is centered on one long wall and juts out into the room about 1/3. The bleacher/balcony wall is across from the stage.

    They have for year "tried everything" to the point where they were just adding more and more speakers each year (on stands) around the room pointing towards the center. Their solution this year was going to be to "add more speakers" aka, "Some didn't work, more was worse, so we'll add some more ...???"

    What I attempted this year was basically two sets of Kustom Profile Two Speakers in a "flown cluster" about 80% down the runway aimed down and out. This was supplemented by 2 delayed speakers further out into the room and delayed to the time with the main cluster. When the ambient noise level was at something below a roar, we were able to achieve good reinforcement and intelligibility. It was only when I had to push the system "up and over" the noise floor that the bounce began to significantly reduce intelligibility, especially the nearer you got to the end walls (the shorter sides of the rectangle).

    Based on suggestions received so far, I'm going to recommend hanging curtains on the two shorter walls. I was resistant to the more is better mentality with the speakers, but after having survived this (what doesn't kill us makes us stronger ... and also lets others see if we're stupid enough to try it again ....) and taking the "get 'em up high and firing down" concept into account, I can picture it. I guess I'll just have to experiment a little with what we need in regard to getting coverage right without creating too much intermodulation ...

    Is there any software out there that a relative layperson could use to help model this, or do I need to suggest a consultation with a good acoustician?
  8. BillESC

    BillESC Well-Known Member Premium Member

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    Kilmarnock, VA
    You haven't listed where your from but Rose Brand rents curtains and has quite an inventory of sizes. It will help tremendously.
  9. mixmaster

    mixmaster Active Member

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    I recently finished doing our graduation in the gym. Gyms are acoustic nightmares even on the best of days, witch it sounds like you didn't have. Lacking ant details from you post, I can only address generalities.

    Speaker location. If you have the ability, try re-aiming the speakers so they point directly at the audience. Often times, I have seen speakers aimed poorly, either because of lack of knowledge or lack of care, and the sound is pointed at a back wall or the bleachers or something. The result is sound that just bounces around to no great effect. Another common problem is that speakers used to announce games tend to be pointed at the bleachers but all the action is happening on the floor for this event. The only thing that the audience hears is the fourth fifth and sixth reflection or whatever. If the speakers aren't aimed at the audience, the audience will never hear "good" sound.

    Absent any control over the way the speakers are aimed, one could get creative with the decorating committee. Perhaps the decorator could find some curtains to hang on the walls, or some carpet to temporarily roll out on the floor. They get a better looking venue for the night and this would soften the reflective surfaces and absorb some of the extra noise that is bouncing around and make your life better.

    If you have access to an eq, don't be afraid to use it. Dump as much of the low end out as you can get away with. Bass tends to build up fast and mask the high end. By EQing out the low end, you remove the bass and allow the system to work more efficiently with the frequencies you need.

    At some point it may just be necessary to put your foot down and decide that it's loud enough. If pushing the system louder is going to sound worse, there is no benefit to cranking things up. You just get louder crap. This is going to be one of those situations where less is more.

    If the audience is too loud, another thought is to provide another space for the people who aren't interested to go to. Put the bar in the another room, or the back of the room, and move the tables somewhere that you can control the sound better.

    My .02
    Good Luck
  10. dedmeetnky8r

    dedmeetnky8r Member

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    Hi all! This is my first post, so be gentle.

    Yes, gymnasiums and similar rooms are difficult environs to work in. I have done two rooms in the last year that were giant echo boxes and were quite challenging. One was a 9,000sqft room with hard wood floors, reflective side walls, and little acoustic treatment. The other was a smaller 3,500sqft room with high ceilings and concrete walls.

    First off, a big +1 to the advice above. Ok, now for my $0.02.

    The trick to good sound in an reverberant environment is great pattern control. This allows you to put the sound where it is needed and not onto reflective surfaces. One approach is to use very directional cabs, carefully aimed and aligned, to project sound very tightly on the subjects. Make sure you are not aiming the speakers so that reflected sound off walls is coming back directly to the listening area.

    A little volume goes a long way. Once a reverberant room gets above a certain threshold, the echoes build up and simply bury the original sound. Another approach for reverberant spaces is to use multiple smaller cabs distributed and delayed accordingly so that they can provide good coverage at lower volumes. This requires careful setup and planning but can be very effective.

    One more issue - Kustom Profile Two speakers are, well, sorry to be blunt - junk. Furthermore, they are not designed to be flown. Please tell me you did not rig these things into some sort of cluster over actual live people! I can only imagine the comb filtering from these cabs being bunched up together, not to mention the risk of speaker cabs falling on the listeners.

    Do you have any pictures from the event? I would love to see how you set things up and others may find it easier to provide input.

    Have a great day!
    Last edited: Jun 23, 2008

    SHARYNF Well-Known Member

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    I have had to do this sort of gig and even a full concert in gyms so here are some suggestions:

    Get drapes, commando or the likes and you need to hang them around the room above the audience covering at least 1/3 of each wall or more. Hang the drapes AWAY from the wall a few feet, this dramatically increases the effectiveness, since as the sound passes thru the drape, hits the surface behind and then passes thru the drape again.

    Don't forget to drape BEHIND the stage

    Get the speakers up high, you can use scaffolding etc, aim them down at the audience and away from the walls, you are trying to focus the sound on the audience and NO on the offending walls.

    For a concert I use a three way setup with NO low end (under 100 hz) on the upper speaker, and use a sub on the floor for the bass.

    typically you will have a dead spot near the front close to the stage, speakers placed in the front down low will help this area.

    Depending on the distance and coverage I usually add side speakers high up aiming down or a center hung row of speakers aiming down

    You need to use a delay system to allign all of this, since the speakers will all be presenting different delays to the audience and this will muddy the sound.
    I use a BSS mini drive, but you can even use an effects delay processor and carefully listen and match the various sources one at a time back to the front speakers.

    For concerts I have actually made up curved hanging panels that are suspended over the audience to reflect the sound back down but cut down on the flat surfaces

    Since it is mainly voice as mentioned by others, pattern control, proper alignment with different source speaker placement and draping are the key.


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