Isolation Strategies for wall construction

[AudioMedios]

Hey guys...

Sorry to call you but I really need to decide wich way to go.

Do you think I should start a new thread about the whole project I'm about to start?

Thanks.

Ed.

[AVare]

1. The wall design that I originally indicated with stell studs is the best of what have suggested.

2. A new thead with what you want would be good.

3. Floating floors cannot be built to work. They have to be designed as system. Read Paul Woodlock's and Sharward's theads for a good feeling for what is involved.

Andre

[Dan Fitzpatrick]

Resilient channel increases the TL on higher frequencies by 10 to 12 dB. It also reduces the TL at the MAM resonance by 6 to 10 dB. Because the MAM resonance is below 125 Hz, this does not have a negative effect on STC. If you have loud music with high bass content, RC makes the isolation worse.

Andre, this is good info. i just checked IR-761, looking only at single stud wood walls with 16mm gypsum on both sides. you are right that the RC wall performs worse at some frequencies, by over 4 db at 80hz.

when i have time i'll have to compare this effect on more robust walls. it's a difficult call since the single stud wall performs really badly at 160hz, over 16db worse in fact. but if you really are focused on the lows then RC might be questionable.

[Dan Fitzpatrick]

I'm a bit confused here, so what guaranties that a floating floor will be better than a non floating floor?

Hey this is science, I suppose that it is possible to be absolutely certain if a soundproofing is going to work or not. According to the room in a room principle, floating the floor and building the inner walls over it is the best way of acheiving sound isolation. Explain me please because I don't want to build and expensive floated floor just to find that it doesn't work the way I need it.

when you float a floor that creates an air cavity which will have a resonant frequency. so your floor can amplify sound at that frequency. usually this frequency is in the low range. so floating a floor can be bad, unless it is designed so that the frequency in question is extremely low (well below human hearing range). to do this you need a VERY heavy floor (think concrete or brick) and/or a large airspace.

This is science in that construction methods can be tested. however each particular construction is unique and so the tested wall will not always work the same way in the field as it did in the laboratory.

usually only walls are tested, without doors for example. so as soon as you add the door you make it less like the test, so the test will predict performance less well.

[AudioMedios]

when you float a floor that creates an air cavity which will have a resonant frequency. so your floor can amplify sound at that frequency. usually this frequency is in the low range. so floating a floor can be bad, unless it is designed so that the frequency in question is extremely low (well below human hearing range). to do this you need a VERY heavy floor (think concrete or brick) and/or a large airspace.

Great and clear answer. Thank you Dan. I can build a floor made of wood. I plan to build it with 7cm x 4cm wood joists spaced (centers) at 70cm, wich makes a wide cavity that will be filled with fiberglass insulation. Over it 25mm Particle board. Of course the joists will be over 20mm rubberfoam pads.

I'm gonna star a new thread describing the whole project with pictures of the place. It will be called AudioMedios Studio thread.

Thanks and see you there.