Corporate Events Setup Suggestions for Reverberant Room

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STLRiverCityDJ

DJ Extraordinaire
Sep 6, 2016
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St. Louis
www.bestrivercitydj.com
I am setting up for a trivia fundraiser tomorrow night. The room is a "multi-use" room. In other words, a concrete box. I was in the room the other day and when empty it is an echo chamber.

The room measures 90' deep by 45' wide, the ceiling is 19'. There is a permanent carpeted stage at one end that is 24" high x 10' deep and goes the width of the room. The rest of the room is epoxy floor and concrete walls and ceiling. There is some acoustical treatment, but it doesn't do enough.

There are some parts of the trivia where there will be video and music. Other wise it is the normal person reading the questions and whatnot.

My plan is to put two SRX812P on sticks in the front and have them up as high as possible and tilted down and in towards the center. I will have two more further back on a delay. I will also have a SRX828SP at the front in the center of the stage. If I need it I will add a SRX818SP, but I'm not looking for rock concert sound here.

My question is; besides pointing the speakers down and in to keep them from reflecting off the ceiling and walls, what can I do to help out with the reverberations?

I have attached a picture of the room.
 

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Use multiple speakers at a lower volume. Put a delay set halfway down, 1 on each side, delayed by around 38ms.
 
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I think you already got some great suggestions on how to deal with it. However, I wouldn't concern yourself too deeply. Most people booking a DJ expect a competent professional, not a magician. If there is an echo in that room, and they're not paying for the treatments that would fix it... they should expect an echo. Most guests will barely notice, and I don't know that anyone would look unfavorably on a DJ because the room is causing an echo.

We have a popular wedding location here in DC that is a round room, all marble, towering ceilings, and stone pillars. This isn't my gig, but the photo will give you the idea:

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It's simply going to be a lively sound environment. We'll do everything we can to make sure it sounds the best possible, but I can't change the physics of the room.
 
Probably the most sonically challenging venue I ever had was at The Smithsonian in the round "elephant" room.

It was a high end corporate event and thankfully, I was only there to play band breaks.

There were so many guest it was hard to even walk around, but it was a great event!
 
Here's the setup. The reverberation has a decay of about 500ms if my "one thousand" count is right. So, it definitely isn't great.

I was mostly concerned about the intelligibility because this is a trivia night and most of the talking is being done be someone that doesn't have a lot of experience on a mic. I'm not sure how slow they will be able to talk.

I was hired to provide sound and projector. I'm not even DJing anything.

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Looks good .. If you have time, I'd toe in all the speakers a bit more to keep the sound off the side walls .. You'll have less left-to-right reverb time than front-to-back.
 
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Looks good .. If you have time, I'd toe in all the speakers a bit more to keep the sound off the side walls .. You'll have less left-to-right reverb time than front-to-back.

I had them toed in but the comb filtering was horrendous. So I decided to have a bit more reverberation and less comb filtering. Compromises are life in sound.

After it filled with people it wasn't too bad. I got lots of compliments from the organizers about how much better the sound and projection was over last year.
 
Use multiple speakers at a lower volume. Put a delay set halfway down, 1 on each side, delayed by around 38ms.

The delay should be 1ms per foot "forward" of the speakers on the stage. Aside from that, the advice is spot on.

Looks good .. If you have time, I'd toe in all the speakers a bit more to keep the sound off the side walls .. You'll have less left-to-right reverb time than front-to-back.

When doing a "toe in," aim the speakers no closer to a corner than 25ft or 1/3 of the rear wall length. Do NOT point the speakers directly into a corner.

Typical horns will roll off really aggressively above 16kHZ - so you are not losing as much as you think. If you have a low pass filter, start the low pass at 18kHz and pull it down until the slapback is under control. Do not be surprised if you are in the 8kHz range when you notice a significant improvement.
 
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The delay should be 1ms per foot "forward" of the speakers on the stage. Aside from that, the advice is spot on.

I do it by ear, sometimes the numbers just don't work out like they should. I made a hard click track to playback. I stand by the delay speaker and listen to it with my right ear and to the FOH speaker with my left. I keep adjusting on my iPad until it sounds like it is coming to both ears at the same time. Then I adjust the volume until I don't notice a drop in volume when I walk the room from front to back.

When doing a "toe in," aim the speakers no closer to a corner than 25ft or 1/3 of the rear wall length. Do NOT point the speakers directly into a corner.

Typical horns will roll off really aggressively above 16kHZ - so you are not losing as much as you thing. If you have a low pass filter, start the low pass at 18kHz and pull it down until the slapback is under control. Do not be surprised if you are in the 8kHz range when you notice a significant improvement.

Good advice, I'll try that next time. All my audio runs through an X32 so I have almost all the control I would want.

I've done a sine-wave sweep on the system and I did notice it dropped off a lot starting around 14kHz and got to nothing around 18kHz. I thought maybe it was my ears.