Isolation - cheap RSIC-1 substitute?

[smeet]

This is my first post here, sorry for any ignorance or impropriety on my part...

I just got Rod Gervais' excellent book about 1/2 way through the isolation partion of my home studio construction. I also found this site. I learned more in 1 day of reading than in months of googling. Better late than never.

I want to isolate the final layers of drywall on the inside of my room, and I'm trying to decide between a true double wall and using RSIC-1 and hat channels. My room is already narrow (7' x 25'), so I think a double wall would lose too much real estate.

But, RSIC-1 is expensive. I estimate that if I space them vertically every 48", with one on each stud, I need abut 150 of them, so that would come to at least $750, not including the channels. Ouch.

So, is there a poor man's alternative to the clip/channel method? Can I do something along the lines of screwing the drywall directly into the studs using rubber grommets to get partial isolation? I know the screw will short-circuit the isolation, but is there a method similar to that? Maybe a grommet inserted into a hole in the gypsum board and the screw goes through that?

 

[jhbrandt]

Figure again for a 32" to 48" grid. That is not one per stud. If your studs are 16" oc, you can skip 2 studs at a time. Stagger the clips.

Cheers,
John

 

[smeet]

OK, that definitely helps.

Any feelings on my hopes for a cheaper grommet-like solution?

 

[jhbrandt]

Any feelings on my hopes for a cheaper grommet-like solution?

Sorry, NO. Check out Whisper Clips.

- John

 

[Rod Gervais]

I have no idea where the original poster lives - but if it is here in the states the maximum spacing would be 24" vertically - the maximum spacing (by building codes) for drywall support is 24"...... (which is what in indicated as maximum spacing for the hat sections in the link provided)

To the OP......

Whichever clip you decide to use - the manufacturer has a chart (some even have calculators) you can use so that you can determine how many clips you will need to get the job done.

Rod

 

[smeet]

I'm in the Los Angeles area. My mistake, I thought I saw that 48" was the maximum vertical spacing.

The whisper clips look good, and are a bit cheaper than the RSIC-1's I have found. Are all these isolation clips pretty equivalent, or are some better/easier to work with? If it makes a difference, the work is being done by a friend who has done a lot of construction, but never with studio acoustic properties in mind.

If I go with 2-leaf double wall assembly, how much space has to be between the two layers of framing? And will it work to turn one layer of framing 2x4's sideways to save a few inches?

Thanks!

 

[jhbrandt]

Rod is correct (of course). I failed to mention that it is a 32" to 48" horizontal (perpendicular to the stud direction) and 24" vertical spacing. Have a look at the Whisper Clips installation directions. They give you a grid chart.

If you turn the studs sideways it will impact the TL. I don't have any data for a wall like that and it may be close to the same TL as the clips. I don't know.

Cheers,
John

 

[Rod Gervais]

if you go with a double wall assembly and turn the studs sideways you will achieve little - the low frequencies are controlled by stiffness......... so the resonant frequency of the wall would be quite high.

You get slightly better LF TL values with 2x6 24" oc than you do with 2x4 16" oc - all due to stiffness......

with the 2x4's on the side you would be building as very large floppy "drum head" - a recipe for disaster not isolation.

Rod