Alan's rehersal space, recording studio and home theater

[audio_alan]

Hey everyone, great forum! After reading multiple threads, I still have numerous questions, so I decided to post to get your advice...

So, I've decided to take the plunge and finish my basement. Currently I use it as a band rehearsal area, a recording studio, and a home theater. As-is, these areas somewhat overlap. Since I would like to keep the same functionality, I'm thinking that I will keep the area as wide open as possible (except for enclosing the furnace and water heater in a room).

My closest neighbor is about 20 feet from the band area, but currently I don't receive any complaints when my band practices. Having said that, neighbors can change so I would still like to improve upon the sound isolation without hurting my room height or room acoustics. So far I've added 13" of fluffy fiberglass to the rim joist, plus 2" of rigid fiberglass on the inner-most part of the rim joist acting as a bay "cap". The floor joist bays don't have any insulation yet, and I haven't done any chalking. With just that rim joist insulation "done", when the band is playing the sound can still reach the mid to high 70's decibels outside (on the side of the house towards my closest neighbor).

The unfinished ceiling is about 7'7" at the bottom of the joists. I'm considering installing a drop ceiling that attaches to the joists (CeilingMax, CeilingLink, or ???) to preserve headroom, allow access to plumbing, the ability to run wires, and try to absorb as much sound as possible to avoid problems associated with recording in rooms with low/hard ceilings.

Is the addition of insulation in the floor joist bays (with R-19 or R-30), plus an angled valance around the perimeter (with more insulation behind the valance), and the ceiling tiles enough to knock down the decibels by another 5 db or so? Or, have I already gained most of the improvement already from insulating/capping the rim joist, resulting in minimal improvement at best from the additional materials?

I've considered sheetrocking the ceiling, but then I'd need to acoustically treat it as well (which would lower it even further). That would probably reduce the ceiling height to a level that I would be unhappy with. Assuming that the drop ceiling and additional insulation will be inadequate to make a noticeable sound drop outside, is there much I can do to improve isolation from the outdoors while still keeping a drop grid ceiling in the plans? Would an additional layer of sheetrock under the subfloor be very effective in this scenario?

Another concern I have is this: Getting lumber and sheetrock through a small hallway and making a 90 degree turn down basement stairs sounds like a major pain. So, I'm planning on adding a new door at the top of the basement stairs that goes straight into the backyard. (Then bringing materials into the basement will be a straight shot.) However, I'm concerned that adding the door will add yet another place for sound to escape. My friend (who is helping me on this project) is suggesting a solid core fiberglass door so it won't require maintenance like regular hardwood doors. Would one of those, with the jam sealed properly, be equivalent (sound blocking wise) to the wall that used to be there? Or should I just plan on adding a second door at the bottom of the stairs to help reduce the sound further? I assume a second door at the bottom of the stairs is probably recommended for acoustic reasons anyway, since it's most likely a source of bad sound reflections.

Thanks for any help or insights!

Alan
P.S. I'll post a diagram of my basement with dimensions soon...

[xSpace]

"is probably recommended for acoustic reasons anyway, since it's most likely a source of bad sound reflections."

We did not recommend it but if it were it would be due to the acoustic hole of not having a sold barrier, not reflections.


Get us a plan, some dimensions...welcome

[audio_alan]

Thanks for the response. Below you can see a rough diagram of how my basement is currently laid out with dimensions, purposed doors, the new water control closet (which might end up being a little bigger), and the wall in front of the furnace.

The current plan is to just frame in the perimeter so the spaces can overlap. As you can see, the theater and control room largely share the same space, and the rehearsal area extends somewhat to the left of the staircase, into the control room area. Building interior walls seems like it will just cramp one or more of these spaces. I also really like the open feel of the basement.

Perhaps someone can suggest a more efficient setup? Otherwise, I would still like some suggestions to the originals questions, and any other suggestions are definitely welcome!

Thanks again for any help you can offer!

Alan

[gullfo]

so your home theater speakers extend all the way to the far side of the basement?

if isolation isn't a big concern yet, go with the acoustic tile drop ceiling, build some heavy gobos to stand up and separate the CR and LR space from the home theater a bit and shape the CR a bit. then you can move them as needed (say a family party or selling the house etc. later, if isolation is an issue, you can pull down the suspended ceiling and beef up, add additional walls etc... i'd just focus on getting decent acoustics without a significant change in the structure.

[audio_alan]

Yeah, the back surround speakers are all the way across the room. It might look strange on the diagram, but it works out fairly well. I suppose I could scale down to a 5.1 setup to keep the speakers more in the theater area, but I'd rather keep the 7.1...

I agree with focusing on decent acoustics. That's one of the main reasons I'm finishing the basement. I'm hoping the tile ceiling and extra insulation will add a little more isolation though...

Can someone recommend a few different acoustic tiles? Most of the ones I've looked at are too thick for those joist-mounted ceiling systems. CeilingLink only supports tiles up to 3/4" thick, and CeilingMax supports 3/4" too (but their FAQ says 15/16"). I like the idea of a "no loss" drop ceiling, but those systems seem somewhat limited with tile options due to thickness.

[Jabbaz]

I'm hoping the tile ceiling and extra insulation will add a little more isolation though...

It may add a little high-frequency isolation, but even that likely won't be noticeable/significant... If I remember correctly, the most isolation you can get due to adding room absorption is about 3dB, and that's the difference between a fully echoic room and an an-echoic room. In your case, you're likely starting with a semi-echoic room, so this is less of an opportunity to you.

In a nutshell, if you want any extra isolation to speak of, you'll need to alter the construction of the room(s). If you're willing to lose an inch or two of finished ceiling height, and engage in a fairly extensive construction project, you can do quite a bit.

[audio_alan]

Jabbaz - I was afraid that would probably be the case... unless I buy the really expensive ceiling tiles with something similar to sheetblock on them. Although I'm still skeptical on how much bass those would block as well. Not to mention, those tiles are thicker so they wouldn't fit in those "zero height loss" grid systems. It sounds like I'm going to need to sacrifice some headroom (one way or another), or just be content with any minimal reductions I receive from the current plan...

Any other suggestions? Will adding a layer of sheetrock to the underside of the subfloor help at all?

[Jabbaz]

It depends on the mass of your subfloor. Just to give you some perspective:

If you stick with a single-leaf system (as opposed to Mass-AirGap-Mass), then by DOUBLING the mass of ALL the existing room partitions, you can expect a maximum of a 3dB improvement. If you just beef up the ceiling, not addressing walls, you may not reach that 3dB.

The real improvements come when you go to a Mass-Airgap-Mass construction.

[audio_alan]

I suppose 3 db might be better than nothing, but it will come at a fairly big expense of more labor costs and basically the same amount of material that would have been used to make a regular sheetrock ceiling.

(looking at the diagram) Since my neighbor's house is almost totally above and to the right of my house, would reinforcing the floor just under the area closest to him (the rehearsal area) make any sense? Or would it still get upstairs through the control room or theater room, resulting in about the same loudness on that side of the house?

Thanks again...

[xSpace]

Mass law predicts a gain of 6 dB with each doubling of mass...in theory.

[Jabbaz]

Mass law predicts a gain of 6 dB with each doubling of mass...in theory.

That's right, my bad

Just noticed the windows - these may be weak points in your exterior facade. I would take some measurements outside close to that wall and see if the levels are higher next to them. If this proves to be true, you might have an opportunity here.

(looking at the diagram) Since my neighbor's house is almost totally above and to the right of my house, would reinforcing the floor just under the area closest to him (the rehearsal area) make any sense? Or would it still get upstairs through the control room or theater room, resulting in about the same loudness on that side of the house?

The latter... again you might see some minor improvement, but no one around here would likely be willing to bet anything on it. Generally speaking, localized room acoustics treatments can be effective, but when it comes to isolation, you need it everywhere to do anything worth your effort. Even a small gap in isolation can render all your isolation next-to-useless.

Attached is a floor/ceiling construction often used by basement studio builders around here. If you build this, without item 5 and 6, you would preserve your ceiling height. You could always add 5 and 6 later if the neighbor gets testy!

[audio_alan]

Regarding the windows, I made a window blocker (multiple layers of MDF, sheetrock, and sound board) for the window next to my closest neighbor. It's really heavy and it made a huge improvement in the sound coming out of the window. I'm going to need to build a new one though, since the window frame will be a bit different after we finish the basement. This might be an opportunity to improve upon my last design...

I might just bite the bullet and add the additional layers under the entire floor. It sounds time consuming and expensive, but it might be my only hope for reducing sound levels while keeping my ceiling height as high as possible with a drop ceiling.

What about the rim joist? Should I add vertical boards in the joist bays near the rim to prevent sound from shooting out the rim/siding?

I really don't know a lot about construction, so I appreciate the continued responses to my questions!

[Jabbaz]

Regarding the windows, I made a window blocker (multiple layers of MDF, sheetrock, and sound board) for the window next to my closest neighbor. It's really heavy and it made a huge improvement in the sound coming out of the window. I'm going to need to build a new one though, since the window frame will be a bit different after we finish the basement. This might be an opportunity to improve upon my last design...

I'd suggest you do the measurements anyways. If the window is still the weak link, upgrading other partitions may be a waste. I'd be concerned about the other window, too.

What about the rim joist? Should I add vertical boards in the joist bays near the rim to prevent sound from shooting out the rim/siding?

That's a good question! It's an important detail, but I'm not sure what's the best approach. I'm sure someone else here will know, as I remember seeing something about it on here a while back.

I do remember that after you add the horizontal gypsum boards, you need to add wood blocking next to the joists, over the gypsum, and then caulk the joints to prevent flanking.

[xSpace]

I do remember that after you add the horizontal gypsum boards, you need to add wood blocking next to the joists, over the gypsum, and then caulk the joints to prevent flanking.

Flanking is a by-product of the existing framing, there are only a few ways to overcome this effect and adding additional wood and caulking isn't one of them since the added lumber could become a flanking path.

What would be more descriptive is a picture of what you are referring to audio_alan, you can see what you are looking at, but as often as not, it is not clear on the other side of the screen since we often talk two different languages from the one side to the other.

[audio_alan]

xSpace - I attached a picture (not my basement, but you get the point) to try to explain what I was talking about. What I'm referring to is, instead of the white foam that they've blown into the rim joist (see picture), I was wondering if it would be better to install a solid board or piece of sheetrock on top of the rim, and then caulk it? Or would that be a problem if my foundation ever moves and possibly jeopardize the foundation and/or the floor above? It sounds like that might just be another flanking problem waiting to happen though, and I should probably only insulate the heck out of it, and then just try to decouple the walls and ceiling, right? (Currently I have the rim insulated with 13" of fluffy fiberglass and 2" of rigid fiberglass on the inner most part of the rim -- custom fit to each gap between the joists. Is that good enough?)

Back to the ceiling -- The more I read and think about it, the more I'm leaning towards putting up a sheetrock ceiling. I really would like the piece of mind from having extra isolation from my neighbors (well, really vice-versa!) I'm starting to think that a double layer with green glue, etc is going to be too expensive though because I'm paying some guys to help me, and my budget is already stretched. I could always go back and add a second layer at another date though, right? Instead, how about the following:

Remove all the insulation from the rim joist.
Caulk where the joists meet the exterior wall board.
Reinstall the fluffy and rigid fiberglass on the rim joist.
Caulk the rigid fiberglass into place? (not sure on this one)
Fill the joist bays with R-19 (is R-30 worth it to fill the bays entirely?)
Hang resilient channel from the joists
Rock the ceiling with 5/8" sheetrock.
Hang lights that don't penetrate the ceiling. (I need help on this one - track lighting, sconces, LED, ???)

Regarding walls, I'm thinking:

2x4 framing, (put that special putty around the electrical boxes probably, right?).
Clips or something to decouple from the ceiling (still haven't figured this out totally).
Is 1/2" sheetrock adequate for walls that are next to the foundation wall?
Do I need resilient channel/clips for these external walls as well?
I assume decoupling the framing from the wall to the furnace room would be beneficial though, right?

What I'd really like to shoot for is an additional 10+ db reduction over what I have now (which is just the rim joist insulated without caulking of any kind). Would the above, assuming we did it right, result in at least that much reduction?

Finally, if I do the hard ceiling, then I'd be back to the problems associated with hard ceilings. So, I'm back to losing height because of extra room treatments. When Ultimate Electronics was going out of business, I picked up three 4'x6' fabric covered 1" rigid fiberglass panels fairly cheaply. Would those, spaced off the ceiling 1" in the center of the approximately 16' long x 12' wide live area, be enough to tame the hard ceiling? Or do I need even more/thicker panels and diffusers to help the sound get back close to a drop ceiling's "transparent" quality? (Of course I will be re-installing my rigid fiberglass bass traps in all the corners, as well as spaced out on the walls...)

Thanks again! (Btw, sorry for the long post and if some of these questions are basic or uninformed, but I'm a construction noob and I'm trying to do this right! )