Basement Design for Isolation and Tracking

[booksmart]

Hi folks -

Long time no see! It's been a looong time since I've posted on here - glad to see it's still around.

My wife and I've recently purchased a new house, and I finally have the space I need to set up a recording space - a basement, roughly 18' by 42' (the dimensions in my Skethcup files are accurate).

Here's the layout as it (nearly) is. I haven't yet built the wall to isolate the water heater and the air handler to their own utility closet, nor the wall that creates the storage room. The teal block snaking around the outside of the room is both AC (sends - the return ducts are in between the floor joists) and plumbing, to be isolated by a soffit. The red block is the only portion of the air return that is not set between the ceiling joists. The airhandler and the water heater are both mounted flat on the floor - I'll fix both of those as they are replaced (the airhandler in a year or two, and the water in a year or so with a tankless).



https://dl.dropboxusercontent.com/u/410 ... sement.skp

Since the vast majority of the playing and recording in the space will most likely be me, myself, and I (with occasional friends over for jamming and *maybe* recording), I'm thinking more in the direction of one large space, with storage for instruments and gear in a small room (the room to the North). However, I will need isolation for the ceiling (the living room is over the southern half of the main room - while I don't expect to be incredibly loud, I do have a 2yr old with the energy and throttle of a small rhino). South and East walls are pretty much underground, with the Northern wall mostly covered until about where the utility closet will start (the main reason for putting the instrument and gear storage there).

To go in the alternate direction of a dedicated room for mixing, and a small room for isolation, I've come up with this design:



https://dl.dropboxusercontent.com/u/410 ... t%20v3.skp

With my mixing desk facing the South Wall, an upright piano on either the East or West Wall, and a couch on the other. The yellow walls would be inside out construction (I'm currently working on a design that moves that center wall about a foot and half to the West).

Edited to Add More Details (as per Rules Before Posting ) :

My floor is concrete slab; I am not planning on floating the floor, for vertical space and costs. The Southern and Eastern walls are fully concrete (8' 7.5" high), backed by *yards* of soil, the Northern wall is approximately 50/50 concrete and open studs, to be insulated and drywalled before construction on this begins. The Western wall is partially a massive block of concrete (supporting my front step landing and foyer), and roughly finished drywall (most likely with no insulation) - this can and will be remedied. The "ceiling" is approximately 8'9" high, with open floor joists (2x8, I think), the cavities of which are stuffed with insulation. I do have the main house drain (2' in from the Eastern wall, through the Southern wall) to isolate, too. The construction of the floor above the basement is the 2x8 joists, 16" on center, with a 3/4" plywood sub-floor, then two layers of 3/8" OSB or plywood, then (depending on which room you're in) either pad + carpet, or an engineered laminate hardwood product of some type. There are water pipes crossing the ceiling.

Budget? ...what budget? I intend to implement this over the course of a few years, so a design that works in multiple stages would be a plus. So, starting with the large room concept, than adding individual isolated rooms *if* I need them would be a bonus.

Monitors are powered Event Studio Precision 6s, plus a KRK 10" powered sub.

So, I guess my questions come down to:

If I'm doing an inside out construction ceiling, how do I support it with the soffit running all the way around the room?
The best way to isolate that stairway, and still allow the wife to come in from the rain? An inside out wall airgapped from the current construction?
What kind of wall treatment should I do if I go with the One Big Room concept?

What other questions should I be asking that I'm not?

I've gotten the Gervais book in, and it's my reading material for the next few weeks.

Thanks for reading.

[booksmart]

Okay, so Whisper Clips and RC Channel for the ceiling, and double stud construction for the walls...

Between Whisper Clips, RC Channel, and two layers of drywall (one 3/8", the other 3/4"), how much db reduction am I looking at, and how much vertical space is it taking up?

[Soundman2020]

I haven't yet built the wall to isolate the water heater and the air handler to their own utility closet, nor the wall that creates the storage room

Don't think of those as walls that isolate things: That's not the way isolation works. Rather, think of those walls as part of the complete isolation system. Trying to isolate just one area is like trying to build an aquarium with only one piece of glass...

However, I will need isolation for the ceiling (the living room is over the southern half of the main room -

Once again, the ceiling is not something that isolates by itself; it is part of the complete isolation system, which consists of two-leaves: the existing structure right now is the "outer-leaf" (which might needs some additions in order to complete the envelope), and the new "inner-leaf" that you have to build, which will be the four walls and a ceiling that surround the room. The inner-leaf and outer-leaf are two separate, independent things, and they cannot touch at any point (except where they are both attached to the floor).

To go in the alternate direction of a dedicated room for mixing, and a small room for isolation, I've come up with this design:

You are wasting a lot of space like that, and there are better ways of laying things out for that scenario.

The yellow walls would be inside out construction

The yellow walls for the CR are fine, but the yellow walls for the iso booth are not complete, and are incorrect: you are only showing three sides of the room, but you need all four, and two of those sides are in direct contact with the outer leaf. You'd get very little isolation like that.

My floor is concrete slab; I am not planning on floating the floor, for vertical space and costs.

And also because there is absolutely no need at all to do so! Floors only need to be floated on vary rare, very specific occasions. And yours is most certainly not one of those.

The "ceiling" is approximately 8'9" high,

Nice! That's an excellent height for a basement.

There are water pipes crossing the ceiling.

Can they be moved? If so, it would be good to move them to a location where the will be accessible if need by, without having to tear down the studio to get at them...

So, starting with the large room concept, than adding individual isolated rooms *if* I need them would be a bonus.

That could be done if you design the entire studio like that from the start, allowing for the modifications that you'd need to do later. So your inner-leaf wall and ceiling would have pre-designed "breaks" in them, where you could simply cut through the drywall, sole plates and joists without needing to re-do any of the structural support, and just add in the two leaves to divide the one room into two. Of course, you'd have to do all of the calculations for both versions of the control room in advance, to make sure that both sets of dimensions would work for a control room, and there would be big changes to the control room treatment, but at least you'd minimize changes to the actual structure.

If I'm doing an inside out construction ceiling, how do I support it with the soffit running all the way around the room?

I'm not sure I understand the question: the inner-leaf ceiling is always supported on the inner-leaf walls, regardless of whether it is conventional construction or inside-out construction. The soffit will be built by framing out a section between the ceiling and wall, and putting drywall on it, in both cases. I don't understand why it would be different when framing either the ceiling or the wall, or both, as inside-out.

I've gotten the Gervais book in, and it's my reading material for the next few weeks.

You should also get "Master Handbook of Acoustics" by F. Alton Everest. You'll need that, to learn the basics of acoustics. Rod explains some of that in his book, but only very minimally. You do need to know more than that to design and build a studio.

Between Whisper Clips, RC Channel, and two layers of drywall (one 3/8", the other 3/4"), how much db reduction am I looking at, and how much vertical space is it taking up?

It would be taking up 3/8" + 3/4" + 1-5/8" (hat channel on Whisper Clips) = 2-3/4", plus whatever dimensions lumber you need for the joists.

However, I would not use a combination of two different thicknesses of drywall: 2 layers of ordinary 5/8" drywall would be better, and would only add 1/8" to the total thickness.

- Stuart -

[booksmart]

Okay, question: given that my basement walls are concrete, backed by earth, but with the studs for the rest of the house resting on them, how much isolation will I be losing by using rc to mount the soffitt, and rc to put up two layers of drywall for the celing, and acoustical caulk between the two, but not actually building walls? How much flanking is going to occur? Assume 80-90db for volume (I really don't tend to crank the amps at all, not when tracking, not when jamming, not when mixing).

I.e., like this, with the purple being acoustical caulking:



Also, since most of my questions right now are more about how to put the blessed thing together, should my thread be under the Construction forum?

Oh, and I noticed today, while walking the grounds and giving a visiting friend a tour, that the concrete basement walls are proud of the ground, by about 20" or so, if that makes a difference.

[booksmart]

As a direct reply to your post...

Regarding the airhandler and water heater - sorry, I meant physical isolation. I know there's not much I can do about acoustically isolating them, given the current construction.

I get what you're meaning about the inner and outer leaf construction, but what do I do about having to run a soffitt around the perimeter, to maximize my floor space? If I do my inner-leaf construction completely inside the ductwork, I'm going to lose even more floorspace.

Actually, in the v3 image, there are four walls on each room, I just didn't hide the soffitt construction.

Some of the water pipes *could* be moved (most notably, the hot water pipes), but the cold water in for the house comes in near the drain on the eastern wall comes halfway across, and branches off to the master suite and the half bath (on the other side of the massive block to the south, over the garage), then continues on to the water heater. I have a panoramic picture of the ceiling I'll post later. That one would be verry costly to move. The hot water, I could probably move, and even come up with a more direct path for it. Will need to talk to the wife and a plumber to see what kind of looks I get from them.

I'll read in the construction forum for suggestions on flooring over slab...

Thanks!

Panoramic shots of basement ceiling:

You'll notice there are two walls in the photo (dividing the main room from the northern room). The one with the doorways in it (to the right of the stairwell) is not structural, and will be removed (as will the TV stand hanging from the ceiling). Well... mostly non-structural. Some of it helps hold up the stairwell, which will need to be reinforced when I either move that wooden post a few inches to the right, or close it in and put a doorway in from the right.



Link to fullsize on Flickr

Basement Northern Room

The wall flush up against the water heater (you can just see the overflow tank, all the way to the left), on the other hand, *is* structural, and will be protected accordingly.



Link to fullsize on Flickr

The ceiling between the two rooms (aka, the ugliest place in the ceiling. That's going to be one ugly soffitt).

[booksmart]

Okay... *IF* I do not absolutely have to build exterior walls if I'm going for the One Big Room concept (which I think I would prefer), I've got my soffitt construction figured out: standard framed soffitt, stuffed loosely with insulation (maybe go so far as to use rockwool), and then skin it with rc'd drywall.

[Kevin Young]

I consider double glazing is the best way to create isolation rather than building a wall...as in this way you can keep watching the outside area and track the things simultaneously...

[Soundman2020]

I consider double glazing is the best way to create isolation rather than building a wall...

And you would be wrong. That would NOT be a good way to isolate a room. Commercial double glazing panels have thin glass panes on each side of a thin air gap. Thus, the MSM resonant frequency is very high, so such a panel offers poor low frequency isolation. It is fine for mid-range and high frequencies, but not for lows. Therefor double glazing is not recommended for studios. If you need visibility, then the solution is to use two single-glazed windows, one in each leaf, and each done with thick laminated glass. The thickness needed for the glass can be calculated from the surface density of the rest of the wall.

- Stuart -

[booksmart]

Since the rest of the house takes precedence, there hasn't been much progress made towards the Recording Space (as in, none), but we did find an electrician I can work with. There were zerozipnada outlets in the garage - he added what we asked for, and did it for a reasonable price, and in good time. So.

Today, did an impromptu sound check, with an amp down in the basement. I set up my Egnater Tweaker, and started a loop playing through it (gotta love TC Electronic Alter Ego), and brought the amp up to 75db (about 2.5 on the Master Volume). Closed the door, went outside, and checked the soundlevels. Barely registered on the sound meter (c weighted, slow) with the garage door closed (had to stand within a foot of the garage door to even know something was happening), and the rest of the outside of the house was dead quiet, until I got to the backyard inside the fence (on the other side of the Northern wall). Again, barely registered, had to be within three feet and stay stock still to hear anything.

Inside, was another story. First floor, with the stairway door open, 65db. Door closed, 51-55db, depending on which way you had it pointed.

We're having a new AC put in this weekend (just in time for things to start getting hot around here - under the wire for the win!). We're moving from a 10 seer 13 yr old unit to a multi-mode 18 seer unit. Hopefully, the power bill will make a nice doppler sound as it drops. The same company also does spray foam insulation - open cell and closed cell. We're getting a quote Wednesday for closed foam to go in the garage walls, and the Northern wall (since I'm not planning on it being part of the active recording space).

I'll try and get technical values on the open cell foam, so I know if it'll do me any good to use for my ceiling (I'm thinking open cell foam between the joists, and resilient channel isolating the drywall for the ceiling and interior walls).

[Soundman2020]

and brought the amp up to 75db

Way too quiet for acoustic testing. You say you'll be tracking live acoustic instruments in there, with jamming sessions for your band too, so you'll be putting out easily a thousand time s more energy than that. It will be up around 105 dBC, minimum, and probably even higher.

So you'll need to re-do your tests with realistic levels.

Even if you are only ever planning to mix in there, you'd still need to make it ten times louder: standard reference level for control room calibration is 86 dB.

Barely registered on the sound meter

That's because you are trying to measure something that isn't even there! Turn up your levels to something realist, and measure again. You cannot measure isolation by using levels that are basically undetectable. 75 dB is normal conversation level. Even a normal non-isolated house wall will take that down below ambient levels.

The same company also does spray foam insulation - open cell and closed cell. We're getting a quote Wednesday for closed foam to go in the garage walls,

Closed cell foam is absolutely useless, acoustically. Forget that! And spray foam is not recommended for studio walls anyway, since it can cause bridging and create flanking paths, or leave voids and uneven coverage, which reduces isolation.

Use only fiberglass or mineral wool isolation for your studio.

- Stuart -

[booksmart]

Okay, I get your point regarding testing at more realistic volume levels, but I need to point something out: I'm not in a band, nor do I plan to be in one.

Also, I did not try a bass amp. Might have to set up the Ditto X2 with a bass loop, too...

Regarding the spray foam - The parts of the house I'm getting sprayed with insulation aren't part of the studio construction, if you look at my building diagram ^ up at the original post ^.

How do you like the numbers on Thermoseal 500? http://www.sprayfoampolymers.com/assets ... ations.pdf

Acoustical Properties
Performance in a 2”x 6” wood stud wall.
ASTM E413 STC Sound Transmission
Class 38
ASTM E 90
Hz. Freq. 125 250 500 1000 2000 4000
Trans. Loss 18 29 34 45 46 49
ASTM C 423
NRC Noise Reduction Coefficient = .75
Hz. Freq. 125 250 500 1000 2000 4000
Absorption .23 .52 .87 .71 .77 .75

IF I'm using it, it would be alongside 10" floor joists, resilient channels, and 2 layers of drywall.

[Soundman2020]

The parts of the house I'm getting sprayed with insulation aren't part of the studio construction,

Then why mention it? Not trying to be disagreeable, but mentioning materials that won't be part of the studio, in a thread about the studio, just creates confusion.

Okay, I get your point regarding testing at more realistic volume levels, but I need to point something out: I'm not in a band, nor do I plan to be in one.

Yes, but you have a control room in there: The STANDARD reference level for calibrating control rooms is 86 dB. Testing at 75 means you have less than 10% of the amount of energy needed for the testing. And also it is a rehearsal/tracking/jamming room, where you will have at least one acoustic instrument. Even if that is just you alone playing an acoustic guitar, that will easily be 80 dB, and could go to 85 if you played loud. Sing along with that, and you'll be hitting 90 with no effort. So it isn't reasonable to measure isolation at levels that are ten times lower than what you will actually have in there. If you have amplified instruments in there, then levels will 10 to 100 times louder again. To find out how well your current construction is isolating, you should be producing the sound levels and spectra that will normally be occurring in the studio when it is operating.

How do you like the numbers on Thermoseal 500?

Not very much! Compare that to plain old Owens Corning OC-703 fiberglass insulation (shown in red) vs. Theromseal-500 (show in blue):

NRC Noise Reduction Coefficient for OC-703= 1.10 (vs. 0.75 for Th-500)
Hz. Freq.: 125 -- 250 - 500 - 1000 - 2000 - 4000
OC-703 : 0.65 - 1.01 - 1.20 - 1.14 - 1.10 - 1.16
Th-500. : 0.23 - 0.52 - 0.87 - 0.71 - 0.77 - 0.75

It's not hard to see that the fiberglass greatly out-performs the T-500 at all frequencies, and especially so in the lowest frequencies, which are the most critical, since that's where the MSM resonance is happening.

(The specifications for the Thermoseal don't say which mounting method was used, but I'm assuming it was A mount.)

IF I'm using it, it would be alongside 10" floor joists, resilient channels, and 2 layers of drywall.

Then the TL numbers on that brochure would not be applicable, since it says they are for ASTM E-413 and ASTM E 90. You would have to check the numbers in something like IR-761, IR-766, IR-802, NRCC44692, or RR-169 to get a better idea of how much isolation you would get from that arrangement.

- Stuart -