Gypsum vs Mass Loaded Vinyl??

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

Its usually not an either/or type of situation. When making a wall for minimum
sound transmission, its good to consider lots of variables. One of the
techniques is to have different layers with different sound characteristics so
that the sound gets attenuated in different ways in the different layers. For
example, in my studio at home, I used a sandwich of caulked 3/4" plywood in
between layers of gypsum. I believe it gave me better seperation than just
three layers of gypsum, but I don't have the money to rip it all out and
replace it with gypsum to test. <grin>

-lee-

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

"Ethan Winer" <ethanw at ethanwiner dot com> wrote in message
newsOKdnaQzROy4W-bcRVn-pg@giganews.com...
> Brian,
>
>> Why would MLV be preferrable? <
>
> It's not. What matters for isolation is mass and density, and on that
> basis
> standard sheet rock is a far better value.

I've had good luck layering sheet rock with homosote with gaps between. The
more layers, the better. Homosote is also cheap and dense, and a different
material than sheet rock, which I believe helps.

The mistake I made on the last project was that though I separated the frame
of the room from other rooms (room within a room), I neglected to separate
the studs from the ceiling joists. The sound transmission through the walls
is very low. For all but the loudests sounds, nothing much gets through.
But bass freqencies do go through the ceiling/floor -- right through those
studs. It's not that bad, but given how good the sound containment of the
walls is, I realize how big an issue having any structural connection is
irrespective of how many layers you install over the studs.

--Nick

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

"Ethan Winer" <ethanw at ethanwiner dot com> wrote in message news:<POKdnaQzROy4W-bcRVn-pg@giganews.com>...
> Brian,
>
> > Why would MLV be preferrable? <
>
> It's not. What matters for isolation is mass and density, and on that basis
> standard sheet rock is a far better value.
>

What matters for other purposes however may affect the decision. If
for whatever reason you can't afford to lose 1" in width (or height,
or length), mass-loaded vinyl would be preferable because then you
only sacrifice 1/2". The biggest advantage of MLV is not that it's
More Effective than sheetrock, but that it's Thinner than sheetrock.

And if you're doing the installation all by yourself, mass-loaded
vinyl is definitely preferable! Much easier for one person to throw
around & tack up sheets of MLV than pieces of sheetrock. (Not that
either is really "easy"...)

There's also the school of thought that says you don't want any two
adjacent layers in a layered wall construction to have the same
resonant frequency. Folks used to achieve this by mating 1/2"
sheetrock with 5/8" sheetrock. (Although by the time you've slathered
enough Liquid Nails in between them to make a vibration-free joint
you've effectively got a 3-piece sandwich!) MLV not only has a very
different resonant frequency than either 1/2" or 5/8" sheetrock, but
it als will damp the resonance of any sheetrock it's adjacent to.

One of the advantages of "engineered solutions" such as QuietRock is
that it gives you all the benefits of a sheetrock/MLV/sheetrock
sandwich without all the cost, time, and hassls of having to install
three different layers.