Sports Halls

[lxkev]

I work for a school, they have a sports hall pos 40 by 50 meters wide, very high roof, with a funny shaped roof. Have an RT60 time of at least 6 secs, without amplification its hard to hear someone one meter away.

 

So... 2day the deputy head, came up with this idea......

 

2 speakers flown off the roof at a angle, aimed at where people are standing. will solve the problem as its pointing at them and the people will absorb the sound.

 

Now if ken or simon read this is the lovely yellow building with a green roof with a tube, u can see from E block.

 

Without ease, smart or any other software. How can I explain to the school that wherever the speakers are placed its going to sound like S***, as the space is ;) and that the need to spend money improving the acoustics of the room.

 

 

help :D

[ChrisD]

Get them to hire the kit and prove it. Show them the clap test (clap the wait until the echos stop and then tell them a hall of that size shouldn't do that). Then ask yourself is acoustic padding a sensible option, bearing in mind that it'll have footballs/volleyballs/students thrown at it?

[Simon Lewis]

Kev,

 

I've run a PA in there many years ago.... and the head's idea will not work ;-)

 

The size of the hall compared to the number of people means that there are still vast areas of reflective surfaces. To make it usable, you will have to fit absorption (shielded by perforated zinc plated steel) and/or suspended soft baffles in the roof.

 

It will cost a lot of money, and is exactly the kind of issue that the architect should have dealt with.

 

Your head is unlikely to follow talk of critical distance and reverberent field. He may not take your advice... in which case be prepared to see money wasted... or you may just strike lucky.

 

You could drag me up there - or get Jason Hawkes in, but I suspect he'll balk at the thought of spending money on treatment.

 

Simon

[Solstace]

Even better, lay on a "demonstration" with the kit and pro engineers (from outside your establishment) - that way, there's less argument about whether it's the engineer at fault and not the kit.

 

We made this mistake in our church when we got the new PA - the acoustics were not treated as part of the new PA install. While the (large) congregation have reported some improvements since the new system was installed, most still think the PA sounds like sh :D t, and blame the engineers before even thinking about the acoustics of the building.

 

In my case, the congregation may be right in the sense that some of our engineers aren't very experienced, but they've said the same of services/events mixed by some very experienced "pro's" from outside the church. This is a political minefield that I'm treading every time I clock-in to my new job, and one that I never look forward to dealing with.

[paulears]

it may be worth getting som kit in and a cherry picker or similar to let you try it in different locations. At least that way you will have been able to prove it wont work. A really good test to convince unskilled listeners who have cheque book signing power is to record one minute of spoken dialogue, then cut the individual words up in an audio editor and reassemble in a random manner. Make sure you leave a short space between each word, long enough to allow the average person to write the word down. Then play this from your likely position and ask the people preent to write down the words. If RT60 is large, then the results are interesting - With real sentences, our brains fill in the words we didn't quite hear - random words prevent this. The bean counters, looking at what they have written, and the gaps - will begin to understand. If you plan to repeat the test in a different location, a second track with different words works well.You end up with quantifiable data you can base a proper decision on.

 

I did this at one venue, and the best results were with the newly installed delay loudspeakers turned off! At another, the planned central cluster was worse than smaller speakers, each covering a separate area.

[Simon Lewis]

Ahh... a variation of the Modified Rhyme Test!

 

I get my second year students to evaluate a building with poor acoustics and a "Soundsphere" style SR system using this method. It is quite revealing, and nicely opens up the whole area of speech intelligibility.

 

In LXKEVs situation - I might be wrong - but I suspect they want to pay less for the equipment itself than it would cost to hire demo kit and a cherry picker ;-)

[Mr.Si]

Thought I'd see you posting in here Simon :D

 

Yeah, the roof would be the the most likely place to pub absorption in - Perforated Metal with mineral fibre in the void behind.

 

Should bring the RT down.

 

You'll find that you'll get slap back too from the rear wall, and flutter echoes from the side walls, but this can also be sorted.

 

Of course, you are dealing here with a multi-purpose hall and they are a nightmare some times!

 

sites to visit are

 

this page here

 

and download Building Bulletin 93 (BB93) from:

 

This page here

 

 

The second page may help with acoustic design (V. Good document) and the first page is a good product for use in sports halls.

[Simon Lewis]

Si,

 

As wonderful (or not depending on your experience!*) BB93 may be, Kev's school hall is a good 15 years old, hence BB93 isn't obligatory, and I strongly suspect that they aren't thinking of applying acoustic treatment.

 

We know that it is probably the best way to go, but the fact that the head is trying to rearrange deckchairs... whoops... sorry, loudspeakers, indicates that he expects miracles to happen for little outlay.

 

However, I wonder of anyone has tried applying DDA in such circumstances?

 

On a vaguely related note, I'm being asked to solve problms with a long (~6 second) RT60 in a large building we own. I asked why the architects didn't plan for this during its refurbishment. "Ah" came the reply, "they did, but English Heritage wouldn't let them make any changes" :-)

 

Kev - what do you think the head will go for? £500 of sound kit that doesn't really work, or £5000+ of acoustic treatment?

 

Simon

 

* I have rather annoying experience of BB93 being applied inappropriately ;-)

[Mr.Si]

Granted about the 15 yr old or so, building.

 

Just thought, in the event of advice - it might be worth a look!

 

I've used it for a couple or three school projects for the usual - RT / Internal Ambient noise levels / Sound Insulation criteria etc

 

 

just mentioned it in case lxkev wanted to have a look.

 

 

- although the Guideline Unoccupied Reverberation Time for a Sports hall is 1.5s which I think is just a little bit short for such a big space (maybe)

 

Sorry I'm going off on one - :)

 

anyway - I agree with you about English Heritage!

 

Si

[Nick S]

On a vaguely related note, I'm being asked to solve problms with a long (~6 second) RT60 in a large building we own. I asked why the architects didn't plan for this during its refurbishment. "Ah" came the reply, "they did, but English Heritage wouldn't let them make any changes" :-)

 

My old school had similar problems - large hall, with a good 6s. reverb, making it totally useless for any sound work (except for choral performances), but it's the only space large enough to run concerts and the like. The current speaker setup is just about workable for spoken word, but anything else is all over the place. Interior is listed, so practically every modification presents a problem...

[Andrew C]

I'll be following this thread very carefully. A Grade II* to add some speakers too this year sometime (maybe)... Double cube room (allegedly Wren designed), used both long and short axis for lectures, paneled walls. Why did I say I'd even look at it?

[Jivemaster]

You are entering a political minefield. The only way to prove the point is to demonstrate that the (Dep) Head is a fool - His idea is worthless and we've spent all this money on finding that out. The other problem is that all the contractors will charge more than the kit costs just to say that as a result of tests.

 

Is there anyone with whom you can liaise about sharing multi use of your building and having multi function acoustic treatment applied to enough surfaces at shared cost. I have seen massive acoustic treatment applied in the space between the lighting trapezes and the roof in one cavernous building to turn it into a BBCTV studio.

[Mr.Si]

Yay! guess what - I've just been asked to quote to do sound for an event in a Sports Hall.

 

This event will be for about 400-500 people and will mainly be for speech.

The rest of it will be an unamplified Orchestra with a mic for solos.

Orchestra will be Doing carols - yes this will be in December.

 

But my main thoughts are:

 

Speech Intelligibility in a Sports Hall = Not good/easy/possible with no acoustic treatment. - Lots of Lateral reverberant energy and slapback and general reverberance everywhere.

 

So my plan is:

I'd be using my equipment - so ASS FOH - pair of Medium-Long Throw Mid/Highs on Poles (heavy duty ones) - to achieve a bit of height. Plus a pair of Bass Bins - just incase - will change the crossover to more like 400Hz rather than 150.

I shall also be putting in a delayed pair of speakers on poles to try and aid intelligibilty further back.

 

I'm hoping that the use of these delay fills will help alot.

 

I don't know which way they're hoping to setup the hall, whether stage at one end of length of hall or with the stage at the side of the hall to bring people closer to the stage.

 

What are your thoughts?

 

Ta, Si

 

Edit: P.S. I might have access to 4 DAS 108's also, whci would be useful to distribute direct amplified sound more easily.

[griffter]

We've had quite good success with our Meyer M1D line array in highly reverberant venues, Careful design with Meyers MAPP software has allowed us to direct the sound carefully towards the audience area and minimise the reflections off sidewalls, ceilings etc giving us a higher S/N ratio in the target area. It isn't the solution for every room though!

[trissy]

I do alot of events in a 'sports hall' which has a nasty solid brick wall at the back (yay for reverb).

 

what I have found to a very easy method of making voice slightly more inteligable, is dropping a few bands on the eq (ie. the major ones that bounce)...as long as you dont have any bands, or lots of music or anything, that tends to do quite well.