Loudspeaker selection and placement in gymnasium

Hi, I am working to advise my school on a loudspeaker upgrade in a large school gymnatorium. The space is used for both athletic events, PE class, and concerts / graduations. Holds approximately 1,000 people. Room dimensions: approx/ 104 feet wide (the stage wall) and 84 feet deep. height from loudspeaker in ceiling to heads of audience members seated: approx. 20 feet. The back wall, with bleachers ,actually has many gaps in the cinder blocks with rock wool to absorb some sound, so acoustically, while certainly a live space, reverberation is manageable, particularly with an audience of 500 or more people.
See photos, current system is 4 Community r5 loudspeakers mounted in ceiling, 2 fire down to audience, 2 to the bleachers. the 2 other speakers (in the middle) are actually subwoofers, but the low end they are producing is not that great. The current system sounds ok to those in bleachers and those directly on-axis. However intelligibility falls away fairly rapidly when off axis. Localization is not that great when the action is on stage. Not sure what the coverage angles are on the speakers themselves. Administration is willing to upgrade, ideally using the existing 6 channels of amplification.
In the past, for events such as graduations, I would set up 2 speakers on sticks (JBL eon), roughly on the vertical maroon cinderblock lines (60' apart), with a center fill speaker below and in front of the stage, completely bypassing the ceiling speaker system. Intelligibility was greatly improved but we're looking to install something rather than have to set that up and tear down for every event.

I have a few ideas.
-Keep the 2 loudspeakers that are aimed at bleachers, but use them as delay fill.
-Replace the other 4, hang the new speakers from ceiling a few feet in front of the proscenium, possibly as follows: 2 in the center (1 as a down fill, 1 angled more into the mid/back of the room, get the tweeters as close to each other geographically as possible). 2 as side fills, hung roughly in line with those vertical maroon stripes.

possible loudspeakers:
-yamaha czr12 for center 2 speakers, (rotate the horn so it is 90 degree horizontal, 60 degree vertical 1 as a down fill, 1 angled more into the mid/back of room), czr 10 as side fills (again, rotate so 90 degree is the horizontal coverage). Angle side fills down at appropriate angle to get maximum coverage for audience.
-EV sx300 for all 4 speakers. (published as 65 degree h x v, but excellent coverage to 90 degrees )
-QSC e112 for all 4 speakers, or maybe 2 e112 for center, 2 e110 for side fills published as 85 degree conical.
-or other models to consider in similar price range?

Would probably be using the u bracket matched to each speaker, secured to the girders for any of these speakers, rather than suspending. Girders are about 5' apart.

Any thoughts / suggestions on speaker placement, speaker model?

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FMEng

Well-Known Member
Fight Leukemia
It doesn't sound like you have the budget to do proper engineering and installation, and it's a challenging room. Unless you have the training, licensing and bonding to hang heavy things over people's heads, don't do it. What you are describing to build is a central, directional array. Many have been used in gyms, some good and many bad. Building a cluster from the Sweetwater catalog is likely to be a failure because of poor directional control over the full range of frequencies, and comb filtering where speakers overlap in coverage. A professional designer would use computer modeling to get predictable results, rather than possibly wasting money.

I strongly suspect that the two center speakers are not subs. A sane and reputable installer would not space the full range speakers that far apart in front of a stage, even when doing a tight budget system. The two centers are full range speakers with blown mid and high drivers or damaged crossovers, which is why coverage and intelligibility are suffering. (In gyms, reverb decay time tends to go way up as the frequency drops, and so extended bass harms intelligibility. That may have been a design consideration, purposely not including subs, balancing the system for speech intelligibility during noisy sports events.)

Put your money into pulling down the blown speakers and repairing them. (I think Biamp still supports the Community products.) Repairing the existing system is likely to give better results than throwing random speakers in there. Add some protection limiting to help avoid blowing up more speakers.

For more intimate stage events with floor seating, speakers on stands, with center fill, are probably a good solution because the basketball targets can be put away when they aren't used.
 

TimMc

Well-Known Member
Premium Member
Hi, I am working to advise my school on a loudspeaker upgrade in a large school gymnatorium. The space is used for both athletic events, PE class, and concerts / graduations. Holds approximately 1,000 people. Room dimensions: approx/ 104 feet wide (the stage wall) and 84 feet deep. height from loudspeaker in ceiling to heads of audience members seated: approx. 20 feet. The back wall, with bleachers ,actually has many gaps in the cinder blocks with rock wool to absorb some sound, so acoustically, while certainly a live space, reverberation is manageable, particularly with an audience of 500 or more people.
See photos, current system is 4 Community r5 loudspeakers mounted in ceiling, 2 fire down to audience, 2 to the bleachers. the 2 other speakers (in the middle) are actually subwoofers, but the low end they are producing is not that great. The current system sounds ok to those in bleachers and those directly on-axis. However intelligibility falls away fairly rapidly when off axis. Localization is not that great when the action is on stage. Not sure what the coverage angles are on the speakers themselves. Administration is willing to upgrade, ideally using the existing 6 channels of amplification.
In the past, for events such as graduations, I would set up 2 speakers on sticks (JBL eon), roughly on the vertical maroon cinderblock lines (60' apart), with a center fill speaker below and in front of the stage, completely bypassing the ceiling speaker system. Intelligibility was greatly improved but we're looking to install something rather than have to set that up and tear down for every event.

I have a few ideas.
-Keep the 2 loudspeakers that are aimed at bleachers, but use them as delay fill.
-Replace the other 4, hang the new speakers from ceiling a few feet in front of the proscenium, possibly as follows: 2 in the center (1 as a down fill, 1 angled more into the mid/back of the room, get the tweeters as close to each other geographically as possible). 2 as side fills, hung roughly in line with those vertical maroon stripes.

possible loudspeakers:
-yamaha czr12 for center 2 speakers, (rotate the horn so it is 90 degree horizontal, 60 degree vertical 1 as a down fill, 1 angled more into the mid/back of room), czr 10 as side fills (again, rotate so 90 degree is the horizontal coverage). Angle side fills down at appropriate angle to get maximum coverage for audience.
-EV sx300 for all 4 speakers. (published as 65 degree h x v, but excellent coverage to 90 degrees )
-QSC e112 for all 4 speakers, or maybe 2 e112 for center, 2 e110 for side fills published as 85 degree conical.
-or other models to consider in similar price range?

Would probably be using the u bracket matched to each speaker, secured to the girders for any of these speakers, rather than suspending. Girders are about 5' apart.

Any thoughts / suggestions on speaker placement, speaker model?

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Hi Chris - Here's my take:

First, what @FMEng said. Spot on across the board.

Second, the most "sway" with administration is the athletic department as that's the *presumptive* primary use for a Gymnatorium. Or when the stage gets used, Audinaseum... but if you get Coach on board with your plan there is a better chance of getting more money,

Third, the current system is designed to cover the bleachers and loudspeakers over the court are for players, usually. If there is not full range audio coming from each and every one, the loudspeakers need repair.

Fourth, the reason the loudspeakers need repair is that they've been asked to put our more SPL that the system was designed for, on multiple occasions. A great deal of installing a system that survives assistant coaches and student operators and choir directors is the expensive part. As you're finding, sometimes whatever limiting factors were at play were insufficient to prevent damage. I'd suggest this be further pursued, as much of today's music and player/coach/fan expectations requires a more robust system in general.

Fifth, you really need two systems, one for athletics and the other for stage productions and assemblies, possibly integrating them for occasions when there are participants on the floor AND in the bleachers.

Lots to think about.
 

jkowtko

Well-Known Member
Einstein: "make it as simple as possible, but no simpler".

If your primary concern right now is to provide sound for stage events, here' what I would do if it were my project ...

Forget the ceiling speakers completely.

Start simple ... three speakers L/C/R hung from the ceiling grid where they won't be pummeled by basketballs during the day, pointing towards a line about 20 feet in front of the front edge of the bleachers.

Keep them on yokes, as you mentioned, for easy adjustment. Then you can play a bit with the positioning.

If you need subs, keep them on stage just behind the proscenium. Leave enough cord that you can carry them out and move them our to the front side edges of the stage, or down to the floor in front of the stage for more presence.

If people get tired of hearing vocals "from the ceiling", then get three smaller speakers to use as downfills, with the ability to walk those out to the front edge of the stage or on the floor in front of the stage. Again L/C/R

By L/C/R I don't mean the LCR panning model, I would just set up the Center speaker as mono.

-- John
 
Thank you @FMEng @TimMc and @jkowtko for your insights. I can investigate those center speakers further. Community makes an R5 that is a subwoofer but looks identical to the full-range version of the speaker. I believe that was what originally installed (subwoofer version) but anything could have happened. The gym has QSC amps driving the 6 speakers, with a small black box attached, qsc-dsp-3 I think, that handles the crossover, filters, and limiting, but no user accessible controls. I will try to get the software that interfaces with the dsp-3 box to get more info. Whether the center speakers are subs, or they are full range loudspeakers that are either damaged or have a low pass applied to them (pretending to operate as subwoofers), I can look into the prospect of repairing them or replacing them with the r5 full range model. That way the "athletics" system would have slightly better coverage and higher SPL capability. However, in general athletics has not really complained about the current system.

Agreed, it might make sense to think of it as 2 separate systems, 1 for athletics, 1 for special events on stage such as concerts and graduations (where there would be a qualified operator present). I found the performance of the eons on sticks (tweeter about 7' above ground) was surprisingly good in the space, even the difference in level from front row to back row of audience was not that much. Perhaps because it is a fairly live room, and for those events the system is not competing against crowd noise. @jkowtko the system you described makes sense to me, however 1 aim is to minimize the number of speakers to set up / tear down. Moving heavy subwoofers would be tricky, I forgot to mention there is also a moving wall (sliding panels) that is sometimes used (it physically separates the entire stage from main gym).

While my administration is very supportive, I agree that to truly cover this large a space correctly (consultant, good measurement and modeling of the space, purchasing and installing arrays properly) is beyond the budget. As such I will probably focus more effort on upgrading the wiring, such that if I continue to set up speakers for special events, to at least have power and XLR drops near to the loudspeaker locations to cut down on hundreds of feet of cable runs between foh position and loudspeakers. FOH position for those special events is actually against side wall, about 2/3 of the way back.
I started a new post to address those options (XLR vs audio over cat6), thank you @TimMc for also responding to that post: https://www.controlbooth.com/threads/analog-audio-over-cat6-catrack-and-cat-boxes.49498/#post-437193
 

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