Improve existing studio walls

This is a completely separate enquiry that's not related to my own new studio build in the design forum, so I thought it was best to start a separate thread... The studio that I have been working in since 2004 in the UK (Which isn't owned by me) was built about 15 years ago by a good friend of mine. He didn't really have a clue about acoustics when he was building the place & just did as he thought best. While researching for my new studio build in the USA I started to realise just how much was wrong with the existing place in the UK & have been chatting with the studio owner about doing some work & improving it a little. Here is a rough drawing of the existing walls. I was wondering, if we ripped the batons and aluminum backed foam out & just had the plasterboard with greenglue attached to the thermolite block, would that give him a 2 leaf design? We record, very, very loud heavy metal in a residential area so more sound isolation would be a benefit. How much theoretical benefit would we get from this do you think? Many thanks Nick

do you have any measurements which indicate how much (or little) isolation you current have? probably need some pink noise and sine wave sweeps with a sound meter to get a sense of how much you have currently. in theory moving to a double leaf wall should be better but with the combination of densities as shown, it's hard to say the triple leaf is the only problem. there could be flanking via floor, ceiling, pipes, air ducts, doors, windows, etc which could be the main source of the perceived leakage.

Hi Gullfo, Thanks for the reply :D I played pink noise in the control room at 94.8db at the listening position The center of the live room measured 63.1db with both doors between the control room & live room closed 6" from the window between the control room & live room measured 74db with both doors between the control room & live room closed 6" from the doors between the control room & live room measured 67.5db with both doors closed Outside of the building 6" from the two outside doors (closed) was 67db (no window on the outside of the building) All measurements were C Weighted LP Slow Cheers Nick

hmmmm... if you move away from the outside doors to another part of the building exterior? how loud is it there? what is the floor construction? how are the doors built?

I played pink noise in the control room at 94.8db at the listening position ... The center of the live room measured 63.1db with both doors between the control room & live room closed

Wow! That's only about 30 dB TL. It should be better than that.

Outside of the building 6" from the two outside doors (closed) was 67db (no window on the outside of the building)

That's even worse! Only 27 dB? with 4" concrete block in there? Something is pretty badly wrong. There must be some major flanking going on and/or pretty large air leaks. 27 dB isolation is about what you get from a typical poor quality house wall: simple 2x4 stud wall with 12mm drywall on both sides and no insulation! I don't think just taking back a couple of layers is going to make a huge difference, especially if the leaks are right back at the concrete block. For example, was that concrete block properly sealed before any of the rest was put up? (Sealed with something like paint or plaster, for example).

We record, very, very loud heavy metal in a residential area so more sound isolation would be a benefit. How much theoretical benefit would we get from this do you think?

You are getting around 27 dB right now. Theoretically, with a good wall you should be able to get at least 60 dB, maybe even 65 That's a huge difference. Objectively, every time you drop 10 dB, it sounds about half as loud. So it could be half of a half of a half of a half of what you have now! In other words, your 94.8 dB pink noise would be inaudible outside, since it would be much lower than the ambient level outside. Is that worthwhile? :) - Stuart -