Resilient bars or air gap for sound reduction?

[andybigbassdrum]

I'm aiming to reduce sound transmission from my garage to my neighbour's garage through the party wall. I'm considering using resilient bars to decouple the two layers of acoustic plasterboard from the 4 x 2 studwork (with Rockwool insulation) that will sit approx. 50mm from the brick party wall (i.e. an air gap in between the studwork and brick wall). For now let's forget about flanking as I have another solution for that.

The resilient bars will obviously reduce the amount of sound transmitted through the studwork, but would I be better off abandoning the resilient bars (that are quite costly) and just increasing the air gap between the studwork and party wall? In other words, is an air gap better at stopping sound transmission than a resilient bar system or vice versa?

Thanks in advance...

 

[Lucid]

There's tonnes of web sites that quote the STC's for various construction methods. Here's one, but there are loads of others. It doesn't take long to work out that springy surfaces (plasterboard on resilient bar) are more effective than stud wall. It's all a question of cost versus effort versus the desired effect. Nothing good is cheap or easy, and nothing cheap or easy is good; if it was then we'd all be doing it already, that stands to reason.

You say this is yours on to neighbours garage. Do they spend a lot of time in their garage that they would be disturbed by whatever you're planning to do in yours? If the concern is that the sound would leak through their connecting door in to the house then might it be simpler to offer to change their door to a fire door?

 

[flameport]

In other words, is an air gap better at stopping sound transmission than a resilient bar system or vice versa?

An air gap of any size will be useless.
Think about what is between any sound source and your ears.

 

[Ricardus]

I'm aiming to reduce sound transmission from my garage to my neighbour's garage through the party wall. I'm considering using resilient bars to decouple the two layers of acoustic plasterboard from the 4 x 2 studwork (with Rockwool insulation) that will sit approx. 50mm from the brick party wall (i.e. an air gap in between the studwork and brick wall). For now let's forget about flanking as I have another solution for that.

The resilient bars will obviously reduce the amount of sound transmitted through the studwork, but would I be better off abandoning the resilient bars (that are quite costly) and just increasing the air gap between the studwork and party wall? In other words, is an air gap better at stopping sound transmission than a resilient bar system or vice versa?

Thanks in advance...

The idea of the resilient bar is to decouple the plasterboard from the wall, but if you're building a new studwall which isnt directly coupled to the party wall, then decoupling with resilient bar is probably going to have minimal extra effect. Though it's unlikely to do any harm and the bar can be bought cheap - I got 10 3m bars for £36 delivered from an online supplier.
If you're double lining the plasterboard, you may want to look at a product such as green glue or quietglue pro which you put between the sheets as a dampening compound. It's not cheap at circa £15 a tube (at least 1 tube/8x4 board) but the reviews are overwhelmingly positive.

 

[Sam Gangee]

An air gap of any size will be useless.
Think about what is between any sound source and your ears.

I'm not sure that's right. Think about how double-glazing works.