John Sayers' Recording Studio Design Forum

That particular drawing is one I marked up for another member, so there are a few things I would change. I'll take your questions somewhat in order;

You can use adhesive for the upper layers of gypsum, or you can screw them into the subfloor. Either way, only fasten them around the perimeter. This lets each panel resonate in its own way, and helps isolation quite a bit. If you GLUE all layers together, then you've just made ONE thick panel, and it will have only ONE coincidence frequency, and only ONE resonant frequency, so those two frequencies will be able to get through easier. Coincidence freqs typically run between 1k and about 4 hHz, while panel resonances are around 30-100 hZ.

The Roxul will be fine, especially if all of it is the 2.5 PCF.

I drew the RC that way just for clarity of what went where, but across the joists is the best way, just for the reason you mentioned. When you HAVE to mount RC parallel to joists, one way (if you're using the "Z" shaped variety) is to mount the small flange to the joist in such a way that the rest of the RC is off to the side of the joist. Another way is to always use screws that are only 3/8" longer than the thickness of your wallboard, but that's kind of calling it close.

Celotex, Homosote, sound board; all basically the same product. Sometimes a thin layer of drywall sandwiched between thicker layers is referred to as "sound board".

Be careful not to arbitrarily put TWO layers of soundboard and ONE layer of gypsum on your ceiling - that's already been done, and didn't work very well. You can put wallboard, soundboard, wallboard, or you can put two layers of wallboard, or if your upper leaf is REALLY good and you want a bit of extra bass trapping, you can hang just one layer of 1/2" wallboard on the RC. Usually, though, this won't give adequate isolation.

I personally wouldn't use sounboard as a sandwich in most cases, because wallboard does as well at different thicknesses and is easier to work with IMO.

One of the best combo's for lower leaf is either two 5/8" layers with a 3/8" layer, or (from RC downward) 5/8, 3/8, 1/2" wallboard. Be sure to get RC that's rated for ceiling use (dietrich RC Deluxe is a good choice) and if you use three layers of full thickness drywall I would put the RC on maybe 20" centers instead of 24". Idea here is that the RC is a spring, and you want it to be somewhere near the center of its "travel" for best spring rate. You accomplish that by controlling how many RC's there are per pound of "sprung" weight.

That WILL be your final ceiling. The best way is to run your walls up to within 1/4" of the joist bottoms, then suspend the inner ceiling leaf BETWEEN the walls, leaving a 1" gap between ends of RC and the walls, and a 1/4" gap between the ceiling layers and the walls (which then gets caulked with acoustic sealant) - This method usually requires an extra joist be added near walls, in order to support the ends of the RC. Another way of accomplishing this (at the ENDS of RC, for a "dropped-in" ceiling, is to just put short blocking frames between the two joists on either side of the wall location, and set the blocking frames such that only the narrow mounting flange of the RC is aligned with the block. -

if that's not practical, you can do the entire ceiling as one unit, bringing walls to within 1/4" of the ceiling and caulking both sides with Acoustic sealant. This second method won't give as good isolation between rooms on the same level, because the ceiling is one piece between rooms and will "flank" noise through.

Any time you're fastening into RC, forget glue. Any flanking caused by fasteners transmitting sound will only get to the RC, which is a spring and will absorb it. Use the proper screws, longer for each successive layer, and mark where your screw pattern will be using masking tape at ends, or you can snap chalk lines where the next course of screws goes, whatever works so that you dont put a screw into the one holding the previous layer.

"Or can I still angle by framing, insulation and whatever I use for the ceiling (drywall, panels, etc.) Space will now be extremely limited. " -

Can you re-phrase that? Didn't follow your meaning...

Plumbing - cast iron may be heavy, but it's quieter than any of the plastics. I'm not sure what's available in flexible support for cast iron, but you definitely want soft support for all the plastic.

I've only found TWO of the dozens of books I have on acoustics/studio construction locally - everything else was from Amazon, Powells, Barnes & Noble, etc - Before you buy a book, consider E-books - the choice is almost non-existent so far, but Alton Everest's Master Handbook of Acoustics is available from Amazon in E-book for around $35, or about $25 for the paper version. The search function is well worth the extra $10, although the index in that particular book is pretty good. Something to think about, I have the paper version and STILL bought the Ebook when I found it. Glad I did... Steve

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Great Post Steve - great thread guys - I hope you don't mind me making it stickey

cheers
john

Steve,

What I meant on the angled ceiling question was, in this thread earlier, we were talking about having the center of the control room above the mix position higher or angled up. (Trying to avoid being parallel)

Basically my question was, in the description you are giving here, is to have a flat ceiling up against the joists. Granted, I don't have much room for an angle, but I might be able to squeeze an inch or two in there for some.

I wasn't sure if the flat ceiling is or should be the final interior wall, or if I can or should build a second ceiling that is angled. Give me an hour or two, and I'll try and draw what I'm talking about.

Oh, by the way, I went home last night after reading the other post on the drywall between the joists...small problem here. Upstairs is all hardwood floors (original to the house 1955). It's all nails coming through the subfloor. I wouldn't be able to get anything up there flush.

Also, unfortunately the Roxul I already installed is 4lb. That was the $600 mistake I mentioned earlier in the thread. Don't have much choice, I'll have to use it this time around. (I'll know better the next studio I build).

Is RC1 rated for ceiling or do I need to find this Dietrich Deluxe RC?

Thanks.

Aaron

John, glad you like it so far, sticky is probably a good idea -

Aaron - Actually, I'm not sure if anyone even makes RC1 anymore - it used to be made by US Gypsum, they discontinued it, another company started making it then changed it (spelled R-U-I-N-E-D-) - now, Auralex offers RC-8, which is probably named because it is 8 times as expensive - I think the auralex stuff is around $.73 per FOOT !!?! but it Will work for ceilings - I just found out about the Dietrich stuff not too long ago, and don't have pricing info on it yet - here's a link to what I'm talking about, if you beat me to a price and availability, please post it in the Materials forum -

http://www.dietrichindustries.com/bigdp ... sories.htm

The RC Deluxe is what you want - NOT the RC-2, it won't give nearly the isolation with double legs.

Angled ceilings can get tricky, but you can do it. Just don't violate the 2-leaf rule, a third leaf is a no-no unless it's just absorption material. One way for a sloped ceiling is to mount 22 gauge steel studs on isolators which are fastened to the sides of the ceiling joists - one end is mounted so that the steel stud is almost touching the joist, the other end is down several inches, the intermediate ones are adjusted accordingly. Using these isolators with steel studs negates the need for RC completely.

http://www.kineticsnoise.com/architectural/icw.html

On your nails coming thru the subfloor - get a pair of heavy nippers and clip them off flush. This is your first, last, and ONLY chance to do this so you'll be happy with it later.

The 4 PCF stuff will bias your walls away from good bass isolation slightly, but with increased high mid isolation. Not ideal, but probably workable. Another reason for the extra mass up against your subfloor...

Been up all night on 12-hour graveyard shift, so that'll have to do for now - ... Steve

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Steve,

I had picked up some RC1 a couple weeks ago. I don't know what brand it is or who makes it, but it looks just like the Deluxe RC on the web site link.

The stuff I bought was $2.02 for a 12 foot stick.

I'm still working on the drawings. May have to modify them from the post you just did.

By the way. I don't think they make 22 gauge. At least not according to the suppliers here. It's either 25 guage or 20 guage. The 20 is the beginning of the structural studs. I actually bought the 20 guage because I was expecting to rest the ceiling framing on the wall framing, and having the walls support the weight.

I've already bought the material, but if I need to change this idea, now is the time.

Thanks.

Aaron

Not all companies make all the gauges of studs, so your supplier may not have them. It depends on how you're going with your ceiling which of the two you mentioned would work best - is headroom tight? I'd look back and see, but I'm about out of time til tomorrow.

If you want slanted ceilings, you may want to use the rubber isolators from kinetics or something similar - if you do that, the 20 gauge is what you want. Mount the isolators on recommended centers for your steel studs (follow links to contact kinetics for this info and prices (not cheap, probably around $20-25 apiece), mount isolators on the SIDES of your existing joists, and vary the heights in order to get the slope you need. hang the 20 ga. joists from those, and screw your layers of wallboard to the joists. Keep the joist ends an inch away from walls, keep the wallboard layers 1/4" away, and caulk like crazy when done.

That's one way and a short version of it, but I'm about outa here for now... Steve

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Oh, back to the original subject of the thread, here's a bit of info on Shore, durometer, etc, and how they work -

http://www.glscorp.com/pdf/tips/hardness_tip.pdf

Enjoy... Steve

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Quick window question...Is there a rule that applies to window sizes between control room and live room? 3x5, 4x6, etc.

BTW, good info on the rubber...

Also, Steve on the ceiling part, I've already spent hours installing all that new insulation in the joists. I don't know if it's going to be feasible for me to pull all that out and redo all of it. Not to mention what a pain in the rear, but I don't want to tear up all that new insulation. Are there any other suggestions or possibilities?

Thanks,

Aaron

Here's one of the drawings. Basically similar to yours, without the drywall for mass near the subfloor...

Windows - bigger the size, the more cost and the more loss of TL (although the minute you break the wall for a window that's the MOST difference) Thicker glass, different thickness, wider air space, get all you can of these for max isolation.

Ceiling - it makes almost NO DIFFERENCE which of the two leaves the mass goes in, so long as the two leaves are DIFFERENT.

If you've not already mounted the RC, you can put it on 20" centers instead of 24", and be safe in mounting three layers of wallboard on the RC. Be sure to use at least 1-1/2" WOOD type screws for mounting the RC to the joists, and STEEL types for mounting the wallboard to the RC. Use longer screws for each successive layer, and make marks of some kind to keep track of where each layer's screws are, so you don't hit the first layer's screws with the second or third layer's screws.

I'm temporarily unable to access the site for some reason, but one other point - I need to know the longest span your joists have between supports, and the joist dimensions (2x8, etc - a 2x8 is really 1.5" x 7.25") also distance between joists - that way, I can calculate span for a better idea of support capabilities.

The only downside of putting the most layers on the BOTTOM, is you'll get less "free" bass trapping, so will probably end up needing more treatment in the room.

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Maybe something along these lines???

Edited...removed picture of 3 leaf system, which was wrong...

You must have posted while I was trying to get the site to work - that drawing is perfect, right down to the layer choices on the RC. I still need to know your joist spacing and sizes, just for safety's sake... Steve

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Joists are 2x8. Length is approx 11.5 ft.

Oops. that was length. The spacing for most (not all) is on 16" centers.

Hey, we must be almost in "chat room" mode here - check back in a few and I'll run some span calcs... Steve

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...