Sports Hall Acoustics

[dave-b]

Hi all,

 

I have been asked back to a school I left last year to run sound for a musical put together by the music and drama departments, the school insist on running the event in the school sports hall and as you can probably imagine the acoustics of the hall are appalling. The show is to be run with the stage & band at one end of the hall and an audience of aprox 400 on raised seating.

 

Sound wise I will be amplifying vocals (singing, talking & choir), reinforcing the band and playing backing tracks. In terms of equipment, it has yet to be decided but hopefully will consist of 2x subs and tops plus some monitoring.

 

I am interested in any ideas for improving the acoustics, considering that currently the reverb of the hall is enormous, anything below about 150Hz simply merges into a low rumble and generally music is very wooly and unclear. The hall is aprox 25m by 40m and 15m high, it has a wooden floor and breezeblock walls. The ceiling is corrigated iron! There is a big problem with reflection of the back wall (very audable). The only ideas I have had is to place large crash mats at the back of the hall to reduce reflection. This is an event that must be up and down within a week and the hall cant be remodelled (so no full wall curtains or acoustic panels hanging from the ceiling!). I relize this is asking the impossible but I thought I would see if anybody knew some quick fixes.

 

Thanks,

[gregog]

Have you got any pennies to spend to try and resolve the problem, or not?

[Jerome]

Hi, we have just moved into a sports hall at our college to act as a theatre for three years, similar scenario. The way we found was obviously to black the space out with cotton tabs. If the school would provide these then it would- a. do the sound a lot of good and b. look more like a perfomance space. Maybe you should enquire into the possibility of this. Maybe you already have... I don't know.

 

In terms of the cieling... good luck its not going to change... niethers ours!

 

Jerome

[Sound In Gloucestershire]

have you considered getting the top speakers up higher and pointing them downwards? if you can get any sort of rigging in the air (probably on stands) or however, you could hang the top cabs to give them a more direct approach

[Jerome]

have you considered getting the top speakers up higher and pointing them downwards? if you can get any sort of rigging in the air (probably on stands) or however, you could hang the top cabs to give them a more direct approach

 

We tried that but due to the floor being wood and varnished (I imagine the OP has the same problem) it didn't help a little.

[aidso]

black tabs is going to be the only thing that will help really. Saying that having 400 bodies on tired seating will help too. Remember bodies are get at sucking sound up. We have had to do this a few times. The best way is to put eyebolts either end at the top of the wall and then every 5m or so along the wall and put steel wire rope along. Cheap enough that you can leave it in and also quick in and out. Two people should be able to do it all in a day easy.

[Jivemaster]

IF you can afford to cover at least 50% of the surface area with heavy drape spaced away from the wall by say 200mm or more, then that may improve thngs at a cost. Otherwise there is little that can be done within a zero budget that will have any worthwhile effect.

 

DO NOT use subs if the bass simply rumbles, look at hiring a properly rigged set of line array speakers with experienced operator. Carefully send the sound to the audience NOT the walls.

[Jerome]

Dave-B , can I ask what your plans are for the floor?- stageing, carpet, wood floor, dance floor, etc.

[dave-b]

Thanks for all this,

 

In terms of money, I havn't yet asked the management as I wanted to get some idea of what to suggest first, however, if I get any at all it won't be much. I like the tab idea as there are connection points in the walls that wire could be hung accross all ready. The only problem is laying my hands on some, cheaply, without getting them custom made.

 

For the floor, I havn't got many options. The hall floor is a laminated/varnished wood type thing and the stage and seating are black plywood.

 

The equipment its self is still fairly flexible but the budget is again fairly low, tops will be mounted on poles but there is almost certainly not going to be any proper rigging. Given as a line array and operator will blow the budget and the requirement, is there other ideas for subs? Or are they completely uneeded? Ussually the kick drum and bass amps can cope on thier own but for backing tracks...

 

Thanks

[Sound In Gloucestershire]

with my idea about angling the speakers down, the floor wont be that important once the room is full of people, that way the sound is going where its needed!

[Bobbsy]

Things that will help:

 

-Rent heavy drapes and line all the walls to deaden the room a bit.

 

-When renting speakers, get decent "pro" ones with a known dispersion pattern, planned to cover the audience but as little of the rest of the room as possible.

 

-Locate these speakers as high as possible, angled down onto the audience, avoiding aim at ceiling, back wall or side walls.

 

-Be reasonable in your expectation of SPL. The less level you try for, the less will be bouncing round the room.

 

-Give the gig to somebody else and head for the pub!

 

Your budget will determine how many of these ideas you can combine!

 

Bob

[stagemanagement]

By the "sound" of it, there's not alot you'll be able to do to combat your problems.

 

If it's a school, the least you should be able to do is get some of those big notice board/classroom dividers that are freestanding and dot them around the back and up the side walls of the hall.

They won't do a huge amount for your issues below 150Hz, but they will help to keep the midrange frequencies under a bit more control and should help with the standing wave issues a big concrete rectangle will throw at you.

 

A concurrent post has been automatically merged from this point on.

 

......is there other ideas for subs? Or are they completely uneeded? Ussually the kick drum and bass amps can cope on thier own but for backing tracks...

 

Thanks

 

You have to decide whether muddy backing tracks that are going to affect the audibility of other instruments/vocals are more vital than slightly thin ones that possibly won't aaftect the audibility of other instruments/vocals.

 

Remember your subs are going to cover from around 120Hz and under, but there can still be plenty of oomph around 90-100Hz in most standard 15"/2" cabinets and that should be plenty enough for the purposes of this gig - which is already compromised by the venue choice before anyone else has been involved.

[Killyp]

I'd try and rent out some good speakers with a good dispersion pattern.

 

d&b's E12 is possibly the best full-range box I've heard yet, it's brilliant, and is very controllable. A pair of those + E15X-Subs would give you more than enough welly to fill a good sized hall. It depends on the length of the room, but you may be better off adding in a second pair of speakers further back, such as E8s. The d&b amps give you an option to delay the sound they produce.