Doors & Windows...

rainmaker · Post by **rainmaker** » Mon Nov 28, 2005 10:40 am

Hello,

I recently moved my studio to a new location and have been busy constructing the new space. In my last studio I had built a double-framed wall between the live and control rooms (8 inch airspace in between). This worked well enough for my needs... However, I'm wondering a few things for the new studio to see if I can make some small improvements.

I have read through and searched many of the postings but can't seem to find much info on different kinds of doors. More specifically, the STC ratings between the two most common doors at stores such as Home Depot (mdf wood door or the metal doors filled with foam center). My last studio used the mdf doors to good result. Does anyone have any experience using two of the metal foam-filled doors for a double wall. Which of the two would be better in your collective expereince? I'm leaning towards the wood but don't know much about the others...

Also on windows. Before, I simply made wood frames in each sill and had glass panes cut to fit (1/4 inch thickness in each sill). I've been looking at a pre-made double-paned window that you can get at Home Depot. Anyone used these? Would the four less-thick panes with the small air space between them perform better than the two panes of thicker glass I used before?

Thanks in advance for any advice on these things. I love this web site. It's a great reference!

Post by **sharward** » Mon Nov 28, 2005 5:12 pm

Welcome to the forum!

I would expect the solid core wood doors to be heavier than the metal doors with foam inside. If that is the case, then the wooden doors would be better for isolation, siimply because you'd have more "mass" in the "mass-air-mass" equation.

Definitely get doors that are flat on both sides -- not "panel doors" that have decorative indentations. Such indentations effectively cause the door to be thinner in those areas, which is less mass, which obviously hurts isolation. Thick, flat, heavy = good. And, of course, seals are critical. Here's an example of a seal that Steve (knightfly, the mod) has recommended in the past.

rainmaker · Post by **rainmaker** » Tue Nov 29, 2005 5:20 am

Thanks for the info on the seals... and the panel doors as well. They look pretty but I didn't make the simple connection that they would be thinner at those points.

Anyone have any suggestions/comments on the two different types of windows?

Thanks,
Rainmaker

knightfly · Post by **knightfly** » Tue Nov 29, 2005 2:01 pm

There is no commercially made window I know of that will work for sound isolation as well as a version of what you did in your last place; putting two "thermopane" or "double glazed" windows in the same opening will result in a quad-leaf construction - you will have the resonance of the m-a-m of each double glass, plus the resonance of each of those derivatives combined with the larger air gap between the two double windows, plus the resonances between each and EVERY combination of mass and air - and every frequency where there's a resonance will pass through the overall window EASIER.

Your best bet, if you want better iso than your last place, is just make everything thicker. More air between panes, and thicker panes. Also, smaller surfaces give a bit higher isolation with all other things being equal; so it's best to go for the smallest window that will give you all the visibility you need.

If you're not sure how to figure that part out, let me know; I think I outlined it for someone a few months ago... Steve

rainmaker · Post by **rainmaker** » Tue Nov 29, 2005 3:58 pm

Thanks so much for the advice. I am also wondering if it would be best to go with the two different thickenesses of glass rather than the two 1/4 inch. I'm thinking maybe 1/2 inch and 1/4 inch this time around. I beleive I read on this site somewhere that two different thickenesses would not resonate as much. Please correct me if I'm wrong.

Also, since I'm on the isolation subject. I was wondering something as I was pondering the M-A-M scenario. What I did when I drywalled my double wall was drywall both sides of one of the frames and just the outside of the other (two layers) since I couldn't get in there after it was closed off. (See Fig. 1 below) I'm now wondering if this wasn't such a good idea since this somewhat eliminates the bi-leaf construction... or am I way off here? I guess this is still M-A-M. I could still go in and take that inside layer out if this would improve my double wall since the tape and texture hasn't been done yet. Thanks for all your help!

Rainmaker

Figure 1. (D=drywall and I=insulation and -=air)
Crossview section of my double wall.

DDID-----IDD
DDID-----IDD
DDID-----IDD
DDID-----IDD
DDID-----IDD
DDID-----IDD
DDID-----IDD
DDID-----IDD
DDID-----IDD
DDID-----IDD
DDID-----IDD

knightfly · Post by **knightfly** » Tue Nov 29, 2005 8:25 pm

By all means, if you want max isolation you only want TWO masses, as widely separated as possible. In a double frame, you would only want drywall layers on the inside of the inner frame, and the outside of the outer frame. Anything else will lessen your isolation given the exact same overall wall thickness and amount of material. The only exception to this would be a few dB improvement in the midrange using more than two leaves of mass.

Read this thread

http://www.johnlsayers.com/phpBB2/viewt ... 86&start=0

at least thru mar. 17, for more on wall types/results -

And no, those aren't "typo's" - the isolation really WILL get better when you REMOVE material... Steve

rainmaker · Post by **rainmaker** » Thu Dec 01, 2005 12:03 pm

Thanks Knightfly for that post. The diagram with the pictures of the wall is great and the easiest i've seen to illustrate the differences between wall types. I'm going in tonight and taking out that layer of inside drywall. My wall will now be as shown below in Figure 1. I'm amazed that taking out material will yield in better isolation. I'm just glad I caught this before Friday when the tape/texture guy is coming to start (two days from now). I would have hated myself for assuming my wall was better than my last studio and then having to live with knowing it was inferior... Man, I love this forum!

Figure 1. (D=drywall and I=insulation and -=air)
Crossview section of my double wall.

DDI-----IDD
DDI-----IDD
DDI-----IDD
DDI-----IDD
DDI-----IDD
DDI-----IDD
DDI-----IDD
DDI-----IDD
DDI-----IDD

knightfly · Post by **knightfly** » Thu Dec 01, 2005 6:06 pm

Forgot to cover your glass questions; you mentioned double frames, but not the distance from wallboard to wallboard - I'd have to assume it's at least 8", since two 2x4's = 7" with no space between them whatever...

IF that's the case, then using 1/2" glass one side and 3/8" glass the other side, you would lose about an inch to 1.5" per side for glass and molding, leaving about 5.5" between glasses.

Under those conditions(and with perfect seals), your window would come in at around STC 47, with the TL @ 50 hZ about 32 dB. This is assuming a size of 3 x 6 feet - smaller size would improve the TL a few dB across the board.

Using 1/4" in place of the 3/8" would lose about 3 dB across the board.

HTH... Steve