?kniht ew od tahw :ziuq

[gullfo]

quiz: what do we think about this?

it's a simplistic version of a treatment from Newell's book and which was discussed (without credit) on a you tube video about low budget isolation. basically a large panel trap using a fully damped single layer of 5/8" drywall with the air gap filled with pink insulation. 2x2 cleats top and bottom hold the panels in place at a 6° angle. these would encircle the entire room (with the requisite corner angles). the walls are normal MSM which may or not have insulation in them, some walls may be exterior side or internal partition, assumes 3rd leaf is implemented by this construct. no treatment is defined for the ceiling and is ignored. assumption is ceiling backs on open but insulated attic space. nothing for the floor either and is ignored. assumption is the floor is over an in-ground basement.

does this have any value proposition for people with a $1000 total budget looking for moderate isolation? should the panel thickness, angles be adjusted to avoid regularity?

[Soundman2020]

quiz: what do we think about this?

I think it must be April 1!

Seriously, I suspect that the isolation properties of such "treatment" would be somewhat less than zero! In other words, negative isolation. Three leaf, fully coupled, with variable depth air cavity ranging from zero to a couple of inches, max...? That sounds like a pretty useless waste of time, effort, money and materials. It might have some effect on high frequencies, but I expect it would actually amplify low frequencies....

It might make an interesting broadband panel trap, but not interesting for isolation.

IMHO.


- Stuart -

[gullfo]

i think some of the isolation principles for this approach rely on the bass trapping performed by the panel i.e. it is weakened before hitting the second wall. much the same for any panel / membrane / Helmholtz trapping coupled to a wall - all of which have 3rd leaf effects but rely on the energy transformation to be more absorptive than reduce isolation.

[xSpace]

Glenn,

Assuming you are referring to "Recording studio design", would you know of where in the book I could locate this?

[gullfo]

Newell, Recording Studio Design, pg 238 - Section 8.4 The Geddes Approach

a double angle wall which steers the axial modal energy to oblique modes.

this is definitely different than the you tube video describing a single angle. and to a degree, the double angle approach seems to make more sense than simply a single angle.

[fxdfxd]

Hello

I read that page, and they say that the whole room must be covered with absorber, the slanted pannel are there only to break the big waves into smaller ones, right ? (I'm just curious to know how it works )
And on the side view, the pannel is dual layered, one wood layer, and one gypsum board layer, and between the two a deadsheet 5kg/m2. Maybe there is a difference avoiding it a go single layer ?

-fx

[gullfo]

Newell has a number of different approaches where multiple densities are used in the isolation assembly, whereas the angled panel discussed is really about transforming axial to oblique modes as well as a dense (i.e. LF) membrane absorber versus an actual isolation assembly.