Sound isolation questions

Archived from groups: rec.audio.pro (More info?)

Hi Everyone,

Thought I would post a follow up to my last post. I have done more research,
and here is what I found. Many people seem to recommend the following
approach:

1. Apply mass-loaded-vinyl (1lb/sq ft) to walls - either directly (if it has
the foam backing) or on top of firring.

2. If 1 above is sufficient, apply sheetrock using standard construction. If
not, build resilient channel on top of MLV and apply sheet rock.

I have a drop ceiling, so I could apply the MLV easily enough. The floor
also has ceramic tiles (as does the adjacent control room...) which of
course are problematic. I would apply MLV there too.

In each case, none of the added construction will touch existing walls,
floor or ceiling. Acoustical caulk would be used to fill in gaps and
perimeter.

I have also read about QuietRock. But I have found no pricing info which is
scary. They claim MLV actually only adds about 3-4dB to the STC. In any
case, the MLV generally goes for around $200 for a 4.5' x 30' roll (closer
to $300 for the stuff with foam backing).

What do you think?

Out of curiosity, what SPL would you expect to be coming out of a guitar cab
for recording purposes (measured a foot away)? I am trying to get a feel for
how loud people crank amps in a studio.

thanks,

brian

Archived from groups: rec.audio.pro (More info?)

"Brian Huether
>
> Out of curiosity, what SPL would you expect to be coming out of a guitar
> cab for recording purposes (measured a foot away)? I am trying to get a
> feel for how loud people crank amps in a studio.
>


** Expect up to 130 dB SPL with a mic at 12 inches with say a 100 watt
Boogie.





........... Phil

Archived from groups: rec.audio.pro (More info?)

"Paul Stamler" wrote:
> "Brian Huether" wrote:
>
> > Out of curiosity, what SPL would you expect to be coming out of a guitar
> cab
> > for recording purposes (measured a foot away)? I am trying to get a feel
> for
> > how loud people crank amps in a studio.
>
> Anything from loud conversational level (say 82dB, with a small amp) to
> 140dBA. I usually go the small amp route myself, but in the account of the
> recording of "Brown Sugar" at Muscle Shoals they note that Keith's amp
> (Ampeg stack?) was cranked wide open. It was, of course, in an iso room.

According to Jimmy Johnson in that Tape Op interview, it was a wide open
Fender Twin. It was so loud that he had to use a 77DX and a 20db pad to get
the level down enough so the input of the mic amp wouldn't clip .

-jw