Room acoustics

[mervaka]

Hey guys,

 

I'm involved in a minor renovation of a pub come music venue, which has some rather challenging acoustics. I wondered if you guys had experience with what treatments are practical in such a space.

 

The room is about 6m wide and 15m long, and the first half of the room from the stage has a low 2.4m ceiling, and the far end is about 3m tall. The stage is 30cm high, which leaves just 2.1m of room for the band. All the walls are wooden clad, as is the floor, and is rather unfurnished. So far, we've put drapes around the stage, which has had some successes, but needs to go further to reduce stage volume.

 

When working there I get issues with cymbals and other noises from the stage more than the PA, but first reflections from the walls and ceiling are also pretty bad. Cymbals are definitely by far the biggest culprit though.

 

The catch is, there are pool tables (and those types of people) on the stage when not used as a music venue, so the drapes currently come down, and any future treatments need to be quite hardy, so exposed foam's out of the question. So my question is, what mid/high reflection treatments are available on the tightest of budgets that can withstand being jabbed by pool cues and picked at by pissed people?

 

Dave

[Simon Lewis]

Glass fibre battens in a wooden frame of suitable depth, covered by steel mesh and a loose weave flameproof fabric ...

[J Pearce]

Can the ceiling over the stage be angled to push sound out over the audience rather than back onto stage? Breaking the ceiling up so that it isn't one flat surface would also probably help.

 

Managing reflections tends to lead to a better acoustic than just absorbing them.

 

There are also plenty of acoustically absorbent materials that aren't foam.

[brainwave-generator]

Maybe you could post your question on the Gearslutz Studio Acoustics forum...

 

http://www.gearslutz.com/board/studio-building-acoustics/

 

Whilst the website is more studio orientated, sound isn't particularly picky about how it works (whether in a pub or a studio), and there are some very knowledgable people on there to give a hand.

 

As has been said, glass fibre or rockwool insulation (the latter my preference, they make it specifically for acoustic purposes, available at Studiospares) is a good start. You can get it in 4x2 (foot) sheets, drop these straight into a 4x2 wooden frame, cut holes (with hole cutter) into the sides for more surface area of rockwool, hang them on the walls with steel mesh over the front then covered with acoustically transparent material, such as hessian materials. They need only be 4" thick to reduce the trebly stuff (like splashy cymbals reverbing round the room), but 8" or greater will also trap some bass if you have bass issues, making them ideal for corners. Also, as has been mentioned, ceiling absorption is not a bad plan, making a cloud is fairly simple although hanging it over the public's heads may be your stalling point... so gluing Auralex-type foam to the ceiling may be the safer bet.

[ramdram]

If your budget runs to the expense, what about dark hued heavy drapes around the room, or parts of, hanging off 30mm ish OD steel pipe (sewn on steel rings to the drapes as the suspension thing). Fireproofed of course and possibly chain in hems.

 

Bunched up when no live music, and, easy as to pull around walls when required. Suggest ceiling is not "treated" as you might end up with too dead a sound.

 

Found that this hanging of the drapes worked really well (but was not intended to as it happened) when we put a huge cyc against the wainscot of a VH. Killed off a lot of the echoes so was voted well worth the money.

 

Should be reasonably cue proof and is anything truly pissed patron proof? I suppose tho' you could have the drapes off and stored somewhere when not required??? Using a sort of butchers hook (blunted!) through curtain ring and over the steel suspension pipe/bars.

 

Should anyone be taken ill owing to the emetic affects of too much Coastal or whatever comes out of the taps then at least the drape(s) can be dry cleaned and re-treated...any residual stains are just part of the pattern...

[Simon Lewis]

My response was based on the requirements for low cost, ease of making/fitting and resistance to abuse. Although OK for mid- high frequency absorption, the design needs some change to make it work as a broadband absorber, and I doubt if many pub/venues really want very deep treatments hung on the wall.

 

Drapes are relatively quick and easy to fit but can rob the place of character, and in some cases reduce some of the useful lateral early reflections. Proper drapes of the right weight per square meter aren't cheap either.

Studio treatment is visually intrusive and quite expensive, and would get fiddled with. Personally, I'd avoid it.

 

Simon

[mervaka]

I've already been told that too many drapes isn't preferable, as that was my first suggestion to the manager. Character is indeed the cited reason why. We've currently got slightly pleated drapes around the stage, but I think that's as far as he wanted to go.

 

Budget's there, probably into the hundreds of pounds if need be, but I'm going to have to argue a strong case for anything I need to purchase. I've got a carpenter to hand when all this goes in over the next couple of weeks too, so a bit of DIY is never a problem!

 

So I'm thinking at the moment that angled, battened rockwool or fibreglass panels are the way forward. Will look at installing these at angles incident to the PA and above the drums. The new stage will be carpeted too, which should go some way further with the cymbal problem.

[S&L]

plus 1 for Simon's comments - plus pubs and bars don't need to be perfect, this is my end of the market and we are used to dealing with challenging venues - taking out some of the worst reverberant effects of the room should be enough to give a decent live sound to work with.

[mervaka]

Of course I'm far from aiming from perfection. I'm mostly just trying to find ways of reducing stage noise, given the hard surfaces and low stage ceiling. The room modes are actually quite manageable, just a 120Hz sort of rumble and a few other minor ones.

[S&L]

Of course I'm far from aiming from perfection. I'm mostly just trying to find ways of reducing stage noise, given the hard surfaces and low stage ceiling. The room modes are actually quite manageable, just a 120Hz sort of rumble and a few other minor ones.

 

thinking about your low frequency rumble, I have had this in a few bars where the'stage' is a timber suspended area forming a box over the floor underneath - in one case it actually IS a stage formed and in another it's a slightly raised drinking area but if you give it a kick with your heel you can hear the the 'boom' of the suspended floor. Could this be part of your issue or not? much as I would love manager's at both venues to fill the voids with concrete it's not going to happen and by the time the band and I roll into town all we can do is minimise the problem. In fact each venue on the local circuit has it's own challenges acoustically, whether with stage separation or with the venue itself. in the case of the venues with the low boom I move subs and tops to the front of the stage, on the lower floor, mix the monitors bass light and in one case have the bass amp on a window cill at the rear of the stage to eliminate transmission through the floor.

is it possible you have a similar issue or another identifiable culprit?

[mervaka]

The stage as it is at the moment is a modular temporary stage made of ply, and indeed resonant, and sits on floorboards that themselves are on beams. Works are about to commence to build in a permanent stage. While I'd love to fill it with sand or hardcore or something, I don't see that happening. As an alternative, I was going to use glass fibre loft insulation to damp it instead. I was also going to ask for extra bracing to stiffen the panels.

 

All that said, I do indeed roll the monitors off at a very high level, depending on what's going through it, the FoH sits on the floor anyway, and so far the stage hasn't been an awful problem.

[Brian]

...I was going to use glass fibre loft insulation to damp it instead....

For a few quid more you could use proper stuff.

 

Look for Rockwool RW3/RW4/RW45 etc.

[kerry davies]

Plus one for Brian's post but do the research. Rockwool used to make acoustic fibre at a premium price but some of their 'insulating' material had almost exactly the same properties at a quarter of the costs. This may not be true today but worth checking out.

[mervaka]

I say loft insulation because the last time I looked, a local retailer seems to have amassed a rather large stock of the stuff, and is selling it off for silly money. I appreciate rockwool is the better tool for the job, and will probably use this in the more critical areas, but under the stage I'm just reducing the Q a bit.

[timtheenchanteruk]

rockwool is all silly money atm, I think its the latest subsidised thing, now that CFLs aren't £3 a roll at wickes and B&Q, probably something similar at homebase.