John Sayers' Recording Studio Design Forum Archive

I guess its safe to say thats a decision you should weigh carefully

My step dad does architect/engineer type work, so he did all the calculations of what I needed for the load. So far, so good...

As far as the studio drawings, I did this all myself in autocad. With the great advice from everyone here on the site as to designs and angles, etc.

Aaron

Which mode calculators are you using, and what are your room dimensions? Steve

Well its been a long time since I started my design, but construction has finally started! Thought I'd post my design and a few pictures. Plus I have a few questions of course! This room will be used mostly for post work like mixing/mastering. But also soundtrack creation as well.

This is the last draft of my design. It's been changed a bit from this picture. I'm no longer doing double-walls between the studio and laundry. Also the closet is now a corner closet that is angled. Hoping to get a bass trap effect from this.



This picture shows the entrance to the studio from the laundry room (elegant huh?)


Here is shot from the rear to the front of the room.



This shows the back closet, from the front wall.


And just to round it out a shot from the right wall back to the door(left wall).


Framing is now complete. Next is running electric, then HVAC.

I have a question about soffits though. I'll be installing 2 30 degree soffit walls.
Should I put these up after I complete the outer shell of the room?
In other words, will the walls be "finished" behind the speakers?
Seems like I would finish the wall behind th soffits, because I need those walls and especially
the ceiling in that area, for sound isolation. Whereas the soffit wall is not built for mass,
but just as a plane to extend the speaker baffle. But then would this create a triple-leaf situation
at these points in my room? Does it matter?

Well let's keep it there for now.
Thanks to all active members for the great advice and effort in this community.

Welcome back!

I'm pretty sure you want the back of your soffit walls to be finished for a number of reasons -- isolation being one of them... Plus, it's a firebreak.

I'm curious about your framing. The doorways look rather unconventional -- I don't think they meet code. Plus, is that rubber underneath the soleplates? If so, what kind of rubber is it?

sharward wrote:Welcome back!

I'm curious about your framing. The doorways look rather unconventional -- I don't think they meet code. Plus, is that rubber underneath the soleplates? If so, what kind of rubber is it?

What looks wrong with the door? I had a contractor help do the framing for me, so I would assume it is standard construction.

I floated the wall on neoprene. I didn't want to use small pucks, just wanted to have a consistent layer along the bottom, therefore no gaps to plug. So I used a softer neoprene, 40 durometer. You'll notice it I also used it along connection points with the joists and connecting walls.

Only the wall between the laundry room and the studio is new(and the closet). 3 walls were already framed when I bought the house. They are all exterior walls(against the foundation). Since I couldn't float the existing walls, I'll be using RSIC clips with furring channel on all walls to attach sheetrock (2 layers 5/8" walls and ceiling).

Hashbrown wrote:What looks wrong with the door? I had a contractor help do the framing for me, so I would assume it is standard construction.

I don't see any cripple studs along the top of the door frame. See this page, FIG. 5.

I floated the wall on neoprene. I didn't want to use small pucks, just wanted to have a consistent layer along the bottom, therefore no gaps to plug. So I used a softer neoprene, 40 durometer. You'll notice it I also used it along connection points with the joists and connecting walls.

Did you calculate the overall weight of your finished walls relative to the amount of compression that the Neoprene will accept without being overloaded? Ideally you want to aim for about 10-15% compression in order to achieve the necessary amount of compression for the Neoprene to act as a spring, but not more than that for fear of overloading the rubber and causing it to "bottom out" or wear out prematurely.

For any solid core door (hopefully yours, if you want much isolation) I MUCH prefer a heavier framing method so things don't settle and shift once the door's in - see my sketch about halfway down this page for what I mean

http://www.johnlsayers.com/phpBB2/viewt ... 2&start=15

HTH... Steve

Thanks for the framing tips guys. I checked out the links you've referenced, and I will beef up that door frame.

I didn't explicitly calculate my wall weight. I saw some references to how to calculate the weight, but didn't find the psf ratings for the neoprene. Also most threads were for floating the floors. So I looked at the spacing people were coming up with for floors, figured my weight for the wall would be much more than the floor, so knew I would have to space the pucks closer. Then I wanted to do a consistent strip along the bottom, so I got a softer neoprene (40 duro). I can use the softer neoprene for other applications as well, like decoulign my speakers from the floor, etc, where softer neoprene would be more effective(not much weight involved). So it's somewhat a crap shoot, but most of what we do here is educated guessing anyhow, so I'm not too worried. It's just a personal studio. I'm balancing doing it perfect, with actually doing it!

You can't afford to crapshoot on stuff like this... Sorry. That's the doggone honest truth.

I have a listing for manufactured rubber that says 95 pounds per CUBIC foot - neoprene should be right in there. So 1/2" would come in at around 4 psf, etc... Steve

ok, I figured out my walls to be ~350 psf. 2 layers 5/8" drywall on both sides of the wall(one side mounted on channel). Does that seem in the ballpark?

So now I'm not quite sure what to do with that number. Steve you said you guessed the neoprene at 4psf? That can't be it's max load can it? I know I want to hit around 15-25% of the neoprene's max load in order to get the desired spring effect, correct?

I guess I'm not sure how to calculate how much neoprene I'd need for a 6.5 ft long wall?

Thanks for any insight.

Sorry, I thought you needed the WEIGHT of neoprene, not the weight it can SUPPORT. Now, do you really mean 350 pounds per square foot of wall? Should be more on the order of 20... Steve

Yeah, I figured I'm expressing it incorrectly. I calculated the wall to be a little over 700lbs. The wall has a surface area of about 68 sq ft. Now what I was figuring was that all the weight of the wall rested on a area of the floor that is around 2 sq ft (76 inch long wall at 3 3/4" thick). So I was thinking that the weight of the wall against the floor(and the neoprene) would be something like 350lbs per sq ft. So looks like I'm wrong about that? Obviously I don't kwow a thing about physical engineering!

Ok so is it as simple as total weight divided by sq ft?
So 700/68 = 10.29 psf?

I'm getting a little lost in all the calculations... But here's how to figure it in a nutshell.

Figure 2.3 pounds per square foot per layer of 5/8" sheet rock. If you're using 4 layers, you're looking at 9.2 pounds per square foot, plus the weight of the framing.

I'm assuming your walls are not bearing any weight above them -- that no amount of pressure will be placed on your top plates. This would require that the tops of your walls actually be a wee bit below the ceiling joists.

Just for fun, let's suppose that including framing, you have 20 linear feat of wall that weighs 1,600 pounds. That's 80 pounds per linear foot.

It appears you're using 2x4 construction, which means your soleplates are 3 1/2" wide. One linear foot has a "footprint" of 12" x 3 1/2". Multiply 12 by 3.5 and you end up with 42. That's the number of square inches that your linear foot occupies on the floor.

Your 80 pounds is sitting on 42 square inches. That's just less than 2 pounds per square inch.

Imagine a tiny piece of your Neoprene rubber that's cut to 1" x 1" (by whatever thickness it is -- 1/2" maybe?). Now imagine putting a two pound weight on it. Do you think that Neoprene piece will compress 10-15%? No way. It would probably require 20 times that, maybe 30 or 40 times that. (I'm just guessing here. )

So, clearly, your rubber is severely undercompressed. What's the big deal? An undercompressed elastomer doesn't bounce, and if it doesn't bounce, it may as well not be there.

The reason elastomers are typically cut into "pucks" isn't so much to save material -- it's to decrease the surface area on the elastomer so as to increase the amount of weight per puck, so as to allow it to act as the spring it is meant to be.

Back when I intended to float a floor on my project (I have since decided not to float), I paid a machine shop to test some 1/2" thick 60 durometer EPDM rubber. Here are the results. Learn from the tests I paid $300 for.

Again, you cannot afford to crapshoot this part of your plan. Mess this up, and you could end up with a worse result than if you hadn't attempted to float anything at all.

I welcome any corrections to my mathematics or logic... But whatever the case, you have to calculate the weights and you have to know how much your elastomer will compress.

Oh, one more thing. Don't assume that if a 1" square of Neoprene can compress a certain amount under a certain weight that you can use simple multiplication to figure a larger piece with a proportional amount of weight to get the same amount of compression. That is not true. What makes Neoprene act as a spring is its ability to squish out on the sides. The larger the piece, the disportionately more weight it takes to compress by the same amount. This is due to the decreased ratio of edge surface area to top/bottom surface area. There is a technical term for this but I don't remember what it is. In other words, there is no "universal" compression test for Neoprene -- the compression rate depends on the size of the puck.

Hope that helps...

--Keith