Where do I start? (30X14X13.5) garage. Pic inside

[honkyjonk]

Hey folks,

I want to make this a control room, but I'm wondering if somebody can set me on the right course for figuring out if I need a two leaf system.

Thing is, the neighbors are far enough away (around 500 ft with some trees in the way) that I don't need total isolation. But I want enough to not disturb this peaceful valley too much. I'm wondering if I can get away with simply finishing the room with standard insulation and then two layers of drywall. Perhaps coupling them to the studs in a way that transmits the minimum possible. Or even one layer of drywall.

Anyway, I have a book by Rod Gervais about studio construction on the way.

Just wondering if it's an extroardinarily complicated math problem to figure this out beforehand or if I should start with one layer of the thickest drywall, and add another after cranking it up inside.

I guess I'm asking what would you do if you had a garage like this with just T-11 siding and studs, and you wanted to finish it with the goal of having the sound be non existent to extremely minimal at 500 ft. of distance. Hmmmm

Also, with a system like this, that is not a two leaf system, is it beneficial to use heavy (6-8pcf) Rockwool insulation between the studs?

[Soundman2020]

Hi "honkyjonk". Welcome!

Please read the forum rules for posting (click here). You seem to be missing a couple of things!

I want to make this a control room, but I'm wondering if somebody can set me on the right course for figuring out if I need a two leaf system. ... he neighbors are far enough away (around 500 ft with some trees in the way) that I don't need total isolation.

With a distance of 500ft to your neighbor, you won't need a huge amount of isolation around your studio. But there's another issue here: you are thinking about sound getting out, but what about sound coming in? Does it rain where you live? Do you get hail, wind, thunder. aircraft flying over, cars / trucks driving around? Is there a house close by that might be making noises, such as TV, radio, phones ringing, vacuum cleaner, people talking?... ? Lots of things can mess up a recording session, or a mixing session. You didn't mention if you will be tracking in there, but even if this is just for mixing, it's still pretty much impossible to do that in the middle of a hail storm or thunderstorm if you only have one leaf...

I'm wondering if I can get away with simply finishing the room with standard insulation and then two layers of drywall.

That might be possible, but it all depends on how much isolation you need, and what frequency range you need it for...

Perhaps coupling them to the studs in a way that transmits the minimum possible.

Rather than coupling them to the studs, the goal is to decouple them from the studs! You could do that either with proper Resilient Channel, or with RSIC clips plus hat channel. But once again, that might not give you enough isolation, depending on what your goal is.

Just wondering if it's an extroardinarily complicated math problem to figure this out beforehand

For a single leaf wall: not really. The equations are very simple. These are the equations of Mass Law that apply to all single-leaf partitions. The more complete version of the equation is used to calculate isolation at specific frequencies, so you could do that for several frequencies and draw a graph of your "transmission loss" curve if you want. Here is the basic Mass Law equation:

TL(dB)= 20log(M) + 20log(f) -47.2

Where:
M is the surface density of the panel, and
f is the center frequency of the third-octave measurement band you are interested in.

But if you just want a rough estimate of how much isolation you'll get overall for a given wall, then you can use the simplified empirical version of the Mass Law equation, which goes like this:

TL = 14.5 log M + 23 dB

Where: M = Surface density of the wall, in lb/ft2

Not complicated at all. However, when you do the math you'll be disappointed, as you'll see just how poor the isolation is from a single leaf wall, unless it is VERY massive. That's why the vast majority of studios are done with 2-leaf walls, which use an entirely different set of equations.

Also, with a system like this, that is not a two leaf system, is it beneficial to use heavy (6-8pcf) Rockwool insulation between the studs?

It is ALWAYS beneficial to put insulation in the wall cavity, regardless of the type of construction. That adds acoustic damping to the cavity, which reduces internal resonances greatly, thus increasing isolation. Insulation can add up to about 6 dB of isolation to a fully coupled 2-leaf wall such as yours, and up to 16 dB in the case of a fully-decoupled 2-leaf wall.

- Stuart -

[honkyjonk]

Okay,
I'm back with some more info. Sorry about that first post. I'm guilty of not paying attention to the rules. Hopefully this is a better, more informative post about what I'm trying to do.

Thanks Stuart for the information so far.

So, the location is in the country outside of Portland, OR.

Budget: $5000 tops.

I took some more exact measurements of this room. I'm measuring from the edge of the studs/joists

The roof is sloped as you can see.

Length is 29ft 6 in
Width is 13 ft 4 in
High side of the ceiling is 13ft 3 in
Low side of the ceiling is 11ft 3 in

There is only one layer of T-11 siding on the outside that is nailed to the studs. My plan here is to seal this shell, take out the garage door of course, close that area in, and then to bulk up the walls by adding 5/8" drywall between the studs. After that, the plan was originally to add Resilient channel and one or two more layers of drywall to complete the second leaf. The problem here is that the existing outer walls sit on top of a concrete foundation, and are set back enough from the edge of that foundation (see pic) that the 1/2" depth of the Resiliant channel will not be enough to keep the inner leaf of drywall off of that bottom lip of the foundation. So, the answer, if I choose to keep that bottom foundation wall is just to build another wall and forget about the resilient channel. Hmmmm. Just talking out loud here.

I've also included some pictures of the ceiling joists and support beams. I realize that I can't go off of recommendations off the internet as far as the structural integrity goes. But I included this anyway. I know, the default suggestion for this is hire a structural engineer. Should I double up the studs? Not sure exactly how I would go about strengthening the ceiling, but maybe it doesn't need it.

As far as how loud am I? Well, I would like to have a band going in here and not bother the neighbors (which as I mentioned are around 500 ft. away) I haven't taken measurements yet, but I do have a sound level meter on the way. So I don't have that exact information at the moment.

Concerning the use of the room though, I'd like to have it as a control room on one side, but also be able to have instruments set up on the far end for tracking or rehearsal. So, perhaps one end on the more lively side, with some diffusion, and then the mixing side of the room with more absorption at first reflections points, and trapping in the corners probably all around the room.

First question is, how would you guys go about sealing the outer shell of this building, in particular the corners where the garage is attached to the larger building on one side (this larger building is a grange hall, to be more accurate. Another element to this story, but one I'll skip for now) There is at least one pic that shows how the garage was attached to the edge of the large building. It is far from airtight as you can see. Other areas of concern are sealing the bottom of the frame to the concrete slab/foundation.

On to acoustics. I've used Bob Golds mode calculator for the estimated dimensions after the finishing by taking 6" off of every wall and the ceiling. And it's further estimated by choosing a height that is an average between the low side of the ceiling and the high side. This might be a pointless exercise because it's not a rectangular building. But this is what this analysis looks like of my estimations:

Room Dimensions: Length=28.5 ft, Width=12.33 ft, Height=12.83 ft
Room Ratio: 1 : 1.04 : 2.31
Volume: 4508 ft^3

The calculator says the closest ratio that would be good is this: Dolby's optimum ratios for Film & Music Room" 1 : 1.493 : 2.313

So, anyway, it's a BIG decision right up front to either increase the width of the room (knocking out that foundation wall on one side, excavating and pouring a few more feet of slab, and extending walls and roof) or use the dimensions I already have.
But to get in the BOLT area of good ratios, I need to increase the width of the room. The spacing of modes starts to look a lot better when I add 4 or 5 feet to the width. But again, this is an estimation because I don't have a rectangular room.

I'm looking for suggestions or insights or things I'm not considering about modifying the room size in regards to cost/benefit. I'm on the fence about whether or not to extend the width. One thing that should be mentioned is that the room volume according to my estimations entered into the Bob Gold calculator is around 4500 ft. cubed. To what extent does this volume make it a more manageable proposition in attaining a balanced mixing position on one end AND a good lively sounding recording end of the room? Is the relationship between my the height and width of the room going to be something down the road that I'll be kicking myself for not dealing with up front?

[honkyjonk]

Should I perhaps post this (or a more abbreviated version) in the 'Studio Design' section? Or I wonder if someone could tell me what I'm missing in the information section in order to a few more responses? (besides sound level measurements. That's to come)

The more I'm reading and learning the more my questions change. Perhaps I can just ask one question right now that would help a lot if I could get some opinions.

1. Can someone speak briefly about inherent modal/other acoustic problems in long buildings like this? Specifically, Length=28.5 ft, Width=12.33 ft, Height=12.83 ft (averaged) I have visited the Bob Gold mode calculator. I've looked at the BOLT graph with acceptable room ratios, which this room does not fit into. One would need to widen it, or shorted the length, which I don't really care to do. However, I have what Rod Gervais might refer to as a large medium room in terms of volume (5000 cubit feet, in his words constituting a large room) My room is around 4500 cubic feet. It's nice to have that volume, but it's not anywhere close to any of the desirable ratios, the nearest one being 1 : 1.493 : 2.313

I need to figure out whether to make the room wider at greater cost and time, or if the volume of the room might help enough in the dissipation of energy so that I can work with what I have and save time and money. I want a very good sounding room (for recording) and balanced for mixing. Essentially a one room studio that can potentially sound woody and alive on one end and then on the other end have the ability to mix effectively.

???

[xSpace]

One of the most important things we ask for is budget (it is in the sticky).

That said, let's talk about a control room, no budget required. What kind of control room are you expecting? Is it for personal amusement, local bands, your own work, theater, tv, etc.?

, I would like to have a band going in here and not bother the neighbors

Ok, so you want a multi-function room. That changes everything. Personally you have a pretty good area to develop a control/mixing area plus have a live rehearsal area. Room volume is important for both. 2500 cubic feet for a control room is a great place to start.

In respect to the room ratios let me see if I can help. Ratios are described by the interior boundaries/walls of the inside of the room. So to get the highest degree of isolation you would want to develop a room in room. These rooms would be designed according to a ratio measured to the interior finish of the rooms. Example: Let's say the measurements determined to use where 12'h X 14'w X 16'l. And your isolation requirements could be met by doing a lot of work to mass up the exterior and be able to use 2 layers of 5/8" fire-rated sheetrock on an interior framed 2X4 wall. What you would have to do next is to step out the distance of 2 pieces of 5/8" sheetrock and the 3 1/2 inch framing:

step out material.png

This will let you maintain the accurate measurements while giving you the place to pop lines and place the framing.

Word of advice: Picking a good ratio while important, many a room has been developed that never came close to one of the good ones and just to make it even more acute...some noted people suggest that ratios are not scalable, many are obsolete and the ones they suggest using are pretty much just computer models that address other computer generated models.

So get something close and move on. Volume is king in this respect.

You have bigger issues to consider like HVAC, Electrical, floor plans, doors and windows, etc.

Hope that helps.