John Sayers' Recording Studio Design Forum Archive

First, I hope I have all the Forum "to dos" done...
Second, thanks Stuart for answering my STC example question in the other section. I suppose I was asking the wrong question...

Third, here's my dilemma, idea, plan...I build, mod, and play vintage inspired tube amps, which can be very loud. Moreover, they don't necessarily reach their "sweet spot" unless turned up pretty loud. What I'd like to do is build a modest sized room in my garage where I could turn the amps up pretty loud without 1) having my wife divorce me; 2) completely annoy the neighbors; and/or 3) have the cops called for noise problems.

I don't necessarily need it silent just outside the door but down to a "low rumble" or loud TV would be ideal.

The reason I asked about the STC is I have been going through the NRC-CNRC Gypsum paper seeing the STC's on different double leaf constructions.

Finally, since we are currently renting, I'd like to make it modular to be able to be transported if and when we move. I was just at NAMM and saw quite a few "loud rooms" that did a reasonable job of cutting dbs.

I've done a lot of searching on the site and have seen people talk about a modular system but never seen someone do it.

So, room would be 8x8 or 10x10 inside an unfinished garage on a concrete slab.

I was thinking that I could build double leaf panels that would latch together with a panel roof that would latch together on top.

I'd need to put some rubber between each panel to "seal" them together.

I am worried a bit regarding weight of each panel if I go with 2 layers of 13mm or 16mm dry wall, steel studs with insulation with 2 more layers of 13 or 16 mm dry wall. I know that plywood or MDF maybe better for durability.

here is one of many options in the ir761 document that yields an STC of 56. (Which is where my question on the other forum came from, is sufficient, over kill or what in terms of my needs.) I realize this is meaningless if there are places that aren't seal, etc, etc but am I in the ballpark?

Element Description:
1 single layer of 16 mm type X gypsum board
2 single layer of 16 mm type X gypsum board
3 90 mm steel studs at 406 mm on centre
4 90 mm of glass fibre insulation in cavity
5 single layer of 16 mm type X gypsum board
6 single layer of 16 mm type X gypsum board

I know I need a floor, door, etc but just looking to see if I am understand this correctly and on the right path.

Thanks,

Roger

ps, yes I did see John's "Studio in a container", if only I had that much room!!!

First, I hope I have all the Forum "to dos" done...

So far, so good!

Third, here's my dilemma, idea, plan...I build, mod, and play vintage inspired tube amps, which can be very loud. Moreover, they don't necessarily reach their "sweet spot" unless turned up pretty loud.

So YOU are the guy who goes up to eleven! I always thought you were out there some place...

The reason I asked about the STC is I have been going through the NRC-CNRC Gypsum paper seeing the STC's on different double leaf constructions.

Right, but IR-761 also shows the actual TL data, which is far more revealing, and much more relevant to what you want to do. There are several designs in there that get STC-56, but compare the TL curves of all of those, and you'll see a wide range of variations in the low end.

here is one of many options in the ir761 document that yields an STC of 56

That seems to be page 144? But take a look at pages 134, 145, 290, 296, 307, 317, 322, and 332 as well: they all get STC-56, but there's some major differences in the low end, especially around 63 Hz. Page 296, for example, is a vastly superior wall, compared to page 144, yet they are both rated at STC-56.... I think that is a perfect illustration of what I was talking about on your other thread!

(Which is where my question on the other forum came from, is sufficient, over kill or what in terms of my needs.)

STC-56 done according to page 144 would be underkill, and would not get you what you want. STC-56 done according to page 296 would be pretty darn good.

I've done a lot of searching on the site and have seen people talk about a modular system but never seen someone do it.

Me too! Maybe you will be the first? I'd love to see that. The principle is fairly simple, but the implementation is not so easy.

So, room would be 8x8 or 10x10

SQUARE???? Hmmmm.... Nope! Bad idea.... No room dimensions should be the same as any other room dimension, nor a multiple of it, nor within 5% of it.

I was thinking that I could build double leaf panels that would latch together with a panel roof that would latch together on top.

The basic plan is fine.... the implementation is the problem.

I am worried a bit regarding weight of each panel

You should be! Isolation requires mass. More isolation requires more mass. Extreme isolation requires super-hyper-extreme mass. The panels will be heavy.

2 layers of 13mm or 16mm dry wall, steel studs with insulation with 2 more layers of 13 or 16 mm dry wall.

2 layers of 16mm is about 24 kg/m2. Four layers is therefor 48 kg/m2. Add the framing screws, latches, rubber, insulation, etc., and you are probably looking at around 60 kg/m2. So a section of wall just 2m wide and standard height, would weigh around 290 kg. In imperial terms, that section would be roughly 6' 6" wide, standard 8 feet tall, and it would weigh around 640 pounds. You'd need half a dozen strong men to handle that safely. It might be modular, but portable it ain't! Even if you make your modules as narrow strips just 2 feet wide, each section would still weight around 200 pounds.

I know that plywood or MDF maybe better for durability.

Right!

I know I need a floor, door, etc but just looking to see if I am understand this correctly and on the right path.

You have the right basic idea on how to do it yes, but I think you are underestimating the weight. A booth capable of providing the levels you are talking about is going to weight several hundred pounds, even for a "light weight, low isolation" version, and you'd need a fairly hefty truck to move it.

I was just at NAMM and saw quite a few "loud rooms" that did a reasonable job of cutting dbs.

And they also do a reasonable job of cutting your bank balance down to nothing! More seriously, they are not cheap, and there aren't many that can get you STC-56.

Is there really a need for yours to be modular?

- Stuart -

Thanks Stuart,

I am understanding better...the guitar frequency range is, as you stated, 60-80hz up to 1200 hz. So that is where I need to focus. The TL graphs and tables are more useful!

The main reason for "modular" or portability is that we are currently renting. If I owned this place, I would not worry about it. I need to be able to, hopefully, take it apart at some point in the future if and when we ever move. I'd rather plan to be able to and not have to rather than not have that option.

I am not wedded to STC 56, I just picked a number. I will study and play around with some designs and see where that gets me. For example, pg 349 and 341, we only have 3x 13 mm boards, thicker walls, more fiber and air space, and more studs (right?). The walls will be thicker but possibly a bit lighter with potentially great isolation in the guitar frequencies with an STC of 59-62 (406mm or 610mm on center, respectively).

Also, I thought I read that since the floor is cement slab on earth, I don't need a floating floor, so just some rugs, etc...right?

On overall dimensions, it needs to be NOT a square box, but what about a slightly angled ceiling on one side where the cabinets sit. The floor dimensions would need to be 9'x11' or 7' by 10', am I understanding?

Also, the weight could also be an issue for the ceiling...there's THAT too!!!!



Thanks again,

Also, I thought I read that since the floor is cement slab on earth, I don't need a floating floor, so just some rugs, etc...right?

Right! That's an excellent floor. Nothing else needed.

the guitar frequency range is, as you stated, 60-80hz up to 1200 hz. So that is where I need to focus. The TL graphs and tables are more useful!

The hardest part of the spectrum to isolate.

I am not wedded to STC 56, I just picked a number.

Fair enough, but the comment applies to any STC number: it's not a good way of determining isolation.

Now, in order to find out how much isolation you actually need, you'll have to get a hand-held sound level meter and take some measurements.

it needs to be NOT a square box, but what about a slightly angled ceiling on one side where the cabinets sit. The floor dimensions would need to be 9'x11' or 7' by 10', am I understanding?

Angled walls and ceilings are useful only of the aggregate angle is greater than 12°, and even then, it is only useful for dealing with flutter echo. In other words, the angle between the two surfaces must be greater than 192° or less than 168°. You can do it if you want: it won't hurt, but it won't provide much acoustical benefit. It also wastes space...

Also, the weight could also be an issue for the ceiling...there's THAT too!!!!

Yup! You need to do your math carefully to calculate your ceiling joist dimensions.... or get a structural engineer to do it for you!


- Stuart -

I have done some thinking and, believe it or not, measuring...

Using a decibel meter and an opportunity when no one was home to turn things up and see how loud it was.

My average was 97-98 dbs. My max 110 db. So, I am thinking I probably need 45-50 db of transmission loss to get me to a level not annoying the neighborhood and more importantly, the wife and kids. Which would get me to an average of 40-50 dbs [I think I am looking at this right.] The low end will be the hard part (50-160 hz).

Second, in thinking about the portability of this room, why could each leaf be separable? Essentially, having each leaf independent for moving which would help with weight. So each "section" or "module" or "half wall" would be 1-2xdry wall, insulation, and framing. They would match up open side to open side in assembly giving the 25mm air gap between. I am also thinking I could put some cloth, burlap, or other material over the insulation to protect it during transport (if and when that happens). Like the double leaf picture below, each side is independent and therefore lighter.

With this type of construction, I could build an option from ir761 pages 317-350 with options using type X board. 16mm would obviously be better and then determine if I need 2 layers on each side or not (with insulation).

Am I understanding things or have I missed something? Yes, the ceiling but I would think the same concept applies up there, with all the structural caveats, etc.

Thanks,

Roger