Plugging void in control room window. Suggestions please!

[lozchalk]

Hi,

Im currently constructing a small recording studio for a radio station. The walls are separated double wall with staggered studs and 2 layers of 15mm sound board each side. There will be two control windows with 2 angled panes of 12.8mm acoustic glass.

What should I plug the void with between the window frames? Could I just bridge the gap with wooden stop? How much would this effect the soundproof rating?

Rod Gervais suggests wrapped fibre glass. Does anyone have any other suggestions?

Cheers.

[Soundman2020]

Hi. Please read the forum rules for posting (click here). You seem to be missing a couple of things!

There will be two control windows with 2 angled panes of 12.8mm acoustic glass.

Laminated glass? That sounds like 6mm + 6mm with an acoustic PVB interlayer? That would be fine if you don't angle the glass, but if you do angle it then you should probably go with thicker glass, to compensate for the lost isolation.

Why do you want to angle it? There is no acoustic reason for doing that, and it reduces isolation, so unless there's an overriding reason for angling it, you might want to reconsider.

What should I plug the void with between the window frames? Could I just bridge the gap with wooden stop?

Nope! That would create a flanking path directly between the two leaves of the wall, thus destroying most of the isolation that you achieved by decoupling the leaves.

How much would this effect the soundproof rating?

Easily 10 dB loss. Likely more. There's a lot to take into account, but somewhere in that range.

Rod Gervais suggests wrapped fibre glass. Does anyone have any other suggestions?

Is there some reason why you can't do that? That is, indeed, the usual method.

- Stuart -

[lozchalk]

Great. Thanks.

The glass is 12.8 laminated glass. 2 panes for each window. The reason I'm angling it is to reduce reflections. The client wants to be able to photograph and document the DJs who will be performing in the studio. I realise this will reduce isolation.

I will look into sourcing some fibreglass bar.

Thanks for your help.

[Soundman2020]

Please read the forum rules for posting (click here). You seem to be missing a couple of things!

The reason I'm angling it is to reduce reflections. The client wants to be able to photograph and document the DJs who will be performing in the studio. I realise this will reduce isolation.

OK, fair enough! That's a very valid reason. But in that case, I really would suggest going with thicker glass, to compensate for the lost isolation. I would suggest at least 8+8mm laminated, with acoustic interlayer.

I will look into sourcing some fibreglass bar.

It isn't "bar". It is just ordinary Owens Corning OC-703 semi-rigid fiberglass. You can buy that in most Home Depot stores, as well as other building supply stores.

- Stuart -

[lozchalk]

Ok. Great. Thank You for your advice.

I'm in the UK so we don't have the exact product you mention. I will source a source a similar product.

Thanks again.

[Soundman2020]

I don't know how to make this any more clear for you:

Please read the forum rules for posting (click here). You seem to be missing a couple of things!

I'm in the UK so we don't have the exact product you mention

Yes you do. From the OC website:


The following distributors are available in this country:

Fernhill Stone Ltd
Address:
Fernhill Business Park
Glaslough, Co. Monaghan
United Kingdom
Phone:
(UK) Low Call 0870 224 7201

Email:
info@fernhillstone.com
Web:
http://www.fernhillstone.com


Contact them. If they really do not have OC-703, then you could substitute any good quality semi-rigid fiberglass insulation product, in the range of around 30 kg/m3 density and roughly 10,000 to 20,000 ralys MKS.


- Stuart -