Advice on treating very live space?

[DC-Choppah]

This space is very very live and people have trouble understanding what a person is saying who is running a class in here.

The space is used for a small dog club, but might be used for other functions as well for extra revenue. Perhaps some live music? If we can get this acoustics under control.

The space was treated using ceiling baffles, but it has not helped with the liveness, and lack of intelligibility problem. The students complain they have trouble understanding.

Floor is hard rolled rubber.

Walls are metal, ceiling is metal. Baffles are rockwool style (Soundstopper) with a thin loose plastic cover.

Photos:
https://drive.google.com/file/d/1FJWi0T ... sp=sharing

https://drive.google.com/file/d/1YjS90X ... sp=sharing

https://drive.google.com/file/d/1Ce_QKu ... sp=sharing

Thank you in advance for any advice anyone can offer regarding how to improve this.

[Sam Spoons]

I'm not an expert WRT acoustics (far from it) but I can't see how those baffles are going to help with sound in the room. If it was a concert space with a stage at one end and an audience in the body of the room it might do something useful but your problem is with noise in the room preventing people in the room hearing others speak? I'd certainly consider a 50% coverage of the ceiling with conventional Rockwool based acoustic panels as I think the main problem will be caused by reflections between the floor and ceiling. I have recently been involved in removing and refitting a suspended ceiling in the church where Mrs S runs her dancing school and the difference between the sound with the vaulted ceiling exposed and it being hidden by the suspended ceiling is dramatic. A flat ceiling is going to be much worse than the ceiling in the church WRT sound echoing between the floor and ceiling so either a similar suspended ceiling with acoustically absorbent tiles (as we used) or a significant coverage of acoustic panels on the existing ceiling would be my suggestion.

As I said though, my experience and knowledge is purely empirical beyond what I have learned on these forums and via Google so do get some proper advice before spending lots of money.

[RichardT]

I think you need professional advice here! I guess a professional might have recommended the ceiling baffles, but you need a better one.

The metallic surfaces are going to cause enormous amounts of reflected sound to zoom around the room, which is why the users have intelligibility problems.

It might be better to remove the metal, or put a different surface in front of it, rather than attempt to remediate the situation with vast amounts of broadband absorption.

Any solution is going to be expensive unfortunately.

[DC-Choppah]

Their first attempt at professional advice did not work as you can see. Where else can we turn but SoS?!

Seriously, thanks all. It is much appreciated.

[James Perrett]

I'm not sure the plastic covers are helping as they'll reflect all the high frequencies and those thin panels aren't going to absorb much in the way of low frequencies.

My suggestion would be to rip off the plastic covers and mount the panels in a frame covered with fire retardant fabric and then mount the panels parallel to the ceiling rather than perpendicular with an air gap behind them.

I'm assuming that we are talking about proper Rockwool filled panels - if you are talking about baffles like the ones at

https://www.singersafety.com/ceiling-baffles/

then you probably need to start again completely as they only claim to offer a very limited reduction in noise.

[DC-Choppah]

Yes that is exactly them.

https://www.singersafety.com/ceiling-baffles/

And I do see that they claim to reduce noise by 4-7 dB if installed at the recommended density which is much higher than what was actually installed.

4 dB? Really. Nobody is going to hear that.

[ef37a]

If this is a community amenity then perhaps take the begging bowel round to some builder's merchants and carpet shops in the local area?

I noticed a few years ago that my local B&Q stocked rockwool slabs as well as GF in bags.

If cost is a problem just cover every hard surface you can with something! Even a layer of carpet on a door can help.

I was in a freshly built plaster boarded room about 4x5x4mtrs some years ago and it was very lively when empty. Just rolling out one 1mtr wide roll of GF about 100mm deep made a vast difference to the reverberation.

You can leave GF in its bag and just chuck it in the corners. Go nuts.

Dave.

[MOF]

You can leave GF in its bag and just chuck it in the corners. Go nuts.

I think you’re confusing bass traps with acoustic treatment here. Cutting down reverberation will require covering a large surface area e.g. a back wall.

[Hugh Robjohns]

Their first attempt at professional advice did not work as you can see. Where else can we turn but SoS?.

You turn to a 'professional' that knows what they're doing!

You need an acoustician who understands and has experience of addressing the kind of 'tin barn' industrial unit you're trying to improve.

There are standardised measurement techniques for assessing speech intelligibility in large open spaces, and you obviously need to start with a measurement of the unacceptable room, and an agreed target value after the remedial acoustic treatment, upon which contract payment is based.

For what it's worth, my impression from your pics is that vertical rejections will be a major contributor to the very short critical distance value, and those baffles do nothing to counter that. Panels parallel to the roof would probably be far more effective, but a little harder to hang.

A competent professional installer will also take into account any roof loading issues as a lot of good quality broadband panels can quickly add up to a substantial load potentially exceeding the design capacity of the structure.

[Wonks]

Yes that is exactly them.

https://www.singersafety.com/ceiling-baffles/

And I do see that they claim to reduce noise by 4-7 dB if installed at the recommended density which is much higher than what was actually installed.

4 dB? Really. Nobody is going to hear that.

You are talking about the level of reverb here, not total sound. If you can get the reverb level less than the critical level (normally given as 50% direct, 50% reverb) then intelligibility improves dramatically. So a 4-7dB reduction in reverb level could be enough, but it all depends on the actual level of reverb in the space.

Of course, you need the required density of baffles to get that quoted level of reduction in the first place.

Was budget an issue?

[ef37a]

You can leave GF in its bag and just chuck it in the corners. Go nuts.

I think you’re confusing bass traps with acoustic treatment here. Cutting down reverberation will require covering a large surface area e.g. a back wall.

Yup, knew that MOF but anything the guy can chuck about will help and you don't want naked GF around the place!

Dave.

[Wonks]

Remember it’s a public space, so anything not properly installed is likely to disappear very quickly!

Several rolls of glass fibre? Thank you very much!

[ef37a]

Remember it’s a public space, so anything not properly installed is likely to disappear very quickly!

Several rolls of glass fibre? Thank you very much!

Wot? Shove them up their jumper and pretend to be VERY up the duff?

Dave.

[Drew Stephenson]

Never underestimate the cheek of people who will just walk in and casually take stuff out.
Especially if they stick a black T-shirt on that says STAFF on the back.

[Sam Spoons]

This is one place where saying "bought the tee shirt" might lead to trouble

[MOF]

Never underestimate the cheek of people who will just walk in and casually take stuff out.
Especially if they stick a black T-shirt on that says STAFF on the back.

Reminds me of the Fast Show

https://m.youtube.com/watch?v=_TWSUtKJpY0

[MarkOne]

The other thing is that as this is a public space the issue of public liability must come into play, particularly as this is in the US. Where I am sure there is some building regulation they will have to comply with, so probably a DIY solution may not even be legal (even if feasible)