How would YOU set up my church banquet?

[Moose Hatrack]

We hold our annual church benefit banquet in an 80' x 114' gym. The floor is packed with round tables seating
8 each. No music, only live speakers. Some of the speeches have to overcome the clinks and clanks of people finishing dinner. Here's the gym...
North wall (80' wide) cinderblock
West wall (114' wide) cinderblock
South wall (80' wide) 80% cinderblock and 20% glass
East wall (114' wide) broken up by a second floor mezzanine with various hard surface nook and cranny walls below.
This year the 16'x8' stage will be centered on the West wall. The stage will likely sport two lecterns with a mic on each. It's not a debate, it's host ("interviewer") at one lectern and guest ("interviewee") at the other.
Loudspeaker inventory (no budget for rentals):
2 x QSC KW153
2 x Mackie SRM450v2
6 x Mackie SRM350v2
I have stands for all ten loudspeakers. Flying is not possible.
Question: How would you place the inventory around the room?
History: I've done this for five years with the stage centered on the North (80') wall. I flanked the stage with the KW153's. I placed the two 450's about 15' apart centered on the south wall (facing the stage). I grouped three 350's at the center of the West wall and three 350's at the center of the East wall. It was as bright as you'd expect but nobody complained (except one year when a speaker had a thick German accent, I don't have a knob for accents). The staff at the community center that houses this gym tells you when you rent it, "Our sound system is no good" and they are correct!
Thank you!

 

[MikeJ]

Keep all of your speaker in one line, horizontal with the stage, all facing the audience from the same plane. Never place speaker on the other end facing the stage, the delay and cancellations cause havoc on your coverage.

I would Either evenly distribute your speakers, or place then in clusters of 2. It Os are the speakers all in the same horizontal plane as the front edge of the stage O............OO.............OO.....stage......OO.............OO...............O

You might not even need the speakers closest to the walls. And depending on the setup, they could be used as front fills on the stage, but it really just depends on how close the tables are to the stage and walls

Your other option would be to place one row of speakers about halfway into the Room, but only if you are able to delay them, Table placement might be a problem with this was well.
Do you have any gear that can delay the signal?

 

[Moose Hatrack]

Thank you MikeJ- I did experiment with delay using my Audia 12x4 in 2013. Delay didn't help because, now I see as you as you point it out, the speakers on the other end facing the stage were whacked with delay and cancellations. Rookie mistakes: I'm trying to eliminate them. I can tell you have been where I am because you mention table placement. Several tables will certainly be upstage of the front of the stage on both sides. Placing the stage on the long wall dictates that arrangement in the minds of those who plan table layout. What do you think of placing the speakers exactly as you propose- but at the back of house facing the stage. I have lots more wiggle room at the back of house... back there I'm 8 feet away from the various East walls and I can get a O............OO.............OO...........OO.............OO...............O straight line because I'm not competing with tables?

 

[epimetheus]

Placing the speakers on the opposite side of the room from the stage is not a good idea. Imagine what it would be like to be watching a person speaking at the lectern, but hearing them from behind you...

 

[FMEng]

There is a bigger problem with speakers on the opposite site. 80 feet of delay will make it very hard for the persons talking, as they hear their voice after a 70 millisecond trip across the room.

I like the concept of the speakers spaced along the west wall. I'm not wild about the idea of doubling speakers together. None of the speakers mentioned will array together without phase cancellation problems in their overlap, and nothing is gained by doing it.

This is a case where more in not better. Use just enough speakers to get the needed coverage through most of the room, but no more. I would try doing it with just the 6 SRM350's. Adding a pile of speakers to try to make every last seat good will only ensure that none of the seats are good.

The coverage pattern of the SRM350, with the 10" driver, is broader than the other speakers at all frequencies because bigger cones get narrower. Having all of the speakers the same will make EQing them easier and the results more uniform.

I would also tell the table layout people to get the tables away from the west wall, if they want those persons to hear. They have to compromise a little if they want a good event.

 

[MikeJ]

One speaker each rather than 2 might be better, but if it does not sound two "phasey" then pairs will give you wider coverage with fewer sources. Ideally you would cover an entire room from one point source, or two for stereo. This is generally not practical in a wide gym or ballroom. So distributing speakers is the compromise. Clustering 2 often works well to function as a single point source, but it depends on the speaker and especially the angle of the horn. Usually trying to cluster more speakers than that together makes the problem worse, because of the phase cancelation; the boxes cannot be placed close enough together for the drivers to act as a single source.

Give yourself some time and try a few configurations.

 

[Moose Hatrack]

"bigger cones get narrower" I won't pretend I knew that. Thank you.
"get the tables away from the west wall" I sent a rough sketch to the Potentate of Table layout. I threatened upside down Soundsphere centerpieces on each table as if I don't get my way. We'll see what he says.
"Give yourself some time and try a few configurations" I want to follow this advice but the set up time is limited so here's my plan:
...350...450...350...QSC....350..stage..350...QSC...350...450...350...
The 350's will be on the main out. The 450s and QSCs will be on Effects out (Mackie ProFX12). That should allow me to experiment before the show. I can imagine nudging in the 450s and QSCs when table busing peaks.
"Placing the speakers on the opposite side of the room from the stage is not a good idea" I get away with this in much smaller rooms, but it is easy to understand why it wouldn't work here with all that distance.

 

[lwinters630]

. I threatened upside down Soundsphere centerpieces on each table as if I don't get my way.

LOL

I have run the Mackie in a gym a lot. Then we brought in a Soundcraft Expression 3 SI, Amazing the difference it made all by it self. built in compressors and EX. IMHO this will CLEAR THE AIR a lot. I'd say beg, borrow, or Steel (ops scratch that). we also by passed the house's clipping system. and now can hear more than Yah, yah, yah.

 

[Moose Hatrack]

Good news... The table czar granted me all the real estate left and right of the stage. Hope that doesn't mean ticket sales are down. I've always run the EQ close to flat with no compression. The talent is tame. Since previous years have gotten good reviews, I figured if it ain't fix don't broke it on the preamp side. What would compression give me? Anything else I should try between the mics and the powered speakers?

 

[FMEng]

Stick to the basics and don't worry about compression and other bells and whistles. In your situation, where you probably will be fighting for gain before feedback, adding compression would only create feedback problems.

 

[Moose Hatrack]

"fighting for gain before feedback" Speaking of that, I've always used supercardioid condensor mics to improve gain before feedback. Of course those need phantom power, and that's never been a problem because I've always gone wired to the mixer. To save set up time (it's 200' from mic to mixer x2 mics with this year's arrangement), I'd like to go wireless. I often use SM58s with xlr adaptor cords to transmitter packs with great success. I'd like to use the condensor supercardioid instead of the SM58's but I would need a 48 volt injector for each mic. Is one phantom injector better than another? Or should I just go with dynamic SM58s because I know they work with adaptor cables?

 

[Moose Hatrack]

Conclusion...
I bought a Rolls PB223 to power the handheld mics and feed the beltpacks. Flawlessness. I set up the various speakers as follows...
South wall |-8'-|350|-8'-|450|-8'-|350|-8'-|QSC|-8'-|350|-3'-|16' stage| then the same thing in reverse on stage left.
The 350's alone seemed like more than enough until the crowd showed up. When the emcee started I had to bring in the 450s and QSCs to shout down the crowd. Intelligibility was still excellent and people all over were giving thumbs up to so I left them in. I had a bit of headroom and never climbed into feedback. My son did report some ringing, but i think that was when I couldn't hear over a chatty group at the coffee station behind me. Important note: When the caterer asks if he can set up the coffee station behind the desk, say no thanks.