John Sayers' Recording Studio Design Forum Archive

Hey there.

I've recently moved into a house that has a separate double garage/shed on a concrete slab at rear of property.

The shed measurements are:

Height: 2.9m
Width: 5.5m
Length: 7m

I want to convert it into a studio space where I can track rock drums.

My only neighbour is behind the garage up the hill approximately 10-15 meters away. The garage is built into the hill with approximately 1.5m of the side wall set into the earth.
I'm hoping to eventually track rock drums in there with a reasonable amount of sound absorption.

My budget is 5-10 thousand.

I apologise in advance if I've missed something I'm supposed to have included in this initial post. I read over the 'before you post stuff' but I'm pretty hungover right now
and might have forgotten something.

Here are my questions:

-From reading around this forum, I'm thinking I'll need to build a complete room within room, leaving an air gap between the leafs (correct use of term?)
and line the interior of the garage walls and roof with something sound absorbent? Is this the best idea?

-As the shed has an angled roof, I'm wondering if it's advantageous acoustically to make the room within room design mirror the angled roof, or if I'd be better off building a flat roof?
The advantage of angled roof would allow me to mic drums overhead from a greater hight.

Cheers,

Will
















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Hi Will, and Welcome!

I want to convert it into a studio space where I can track rock drums.

So you will need a lot of isolation, in order to ensure that you don't have the cops knocking at your door every time you play...

The garage is built into the hill with approximately 1.5m of the side wall set into the earth.

That helps, but only on one side. It sounds like the other sides are still exposed to the air.

I'm hoping to eventually track rock drums in there with a reasonable amount of sound absorption.

I think you mean "isolation", not "absorption". Absorption is part of the room treatment that you put inside the finished, isolated room, to make it sound better, but absorption by itself does practically nothing to stop sound getting in or out. that's what isolation does.

My budget is 5-10 thousand.

For isolating a drum room, that's very much on the low side. You have nearly 40 square meters of floor area, and 10k for isolation, treatment, HVAC, and electrical. That implies that you are budgeting just $250 per square meter. The HVAC alone could cost you one third to one half of your entire budget, leaving you with maybe $150 per square meter for all the rest. That's not realistic. A more reasonable budget would be around about three to four times what you are planning. One of my customers in NSW just completed his drum studio that I designed for him. His is a bit bigger than yours (about 55m2). He originally budgeted around 50k for doing that, and went way over by the time he was finished. So I'm familiar with the costs for Australia, and I'm pretty certain that 10k is not going to cover what you want to do. You should re-thing your budget, or the size of your room, or both.

-From reading around this forum, I'm thinking I'll need to build a complete room within room, leaving an air gap between the leafs (correct use of term?)
and line the interior of the garage walls and roof with something sound absorbent? Is this the best idea?

That's the basic idea, yes, but in your case the thin metal shell is not going to be much use as the outer leaf. You will either need to beef that up with more mass, or you will have to go to a 3-leaf solution, which is not ideal but sometimes you have no choice.

-As the shed has an angled roof, I'm wondering if it's advantageous acoustically to make the room within room design mirror the angled roof, or if I'd be better off building a flat roof?

You could do that, yes, but it complicates the build and makes it more expensive. On a very tight budget, I would just go with a simple flat ceiling, in a simple rectangular room.

- Stuart -

Thank you so much for all this info Soundman! You're right, my terms are a bit off. I need to focus on sound ISOLATION first.

Looks like I have some saving to do!

This budget of 10K is for the construction of the room only- I would be tackling room treatment after construction and consider that a separate expense.
I failed to mention there's already electricity connected with a lot of points around the garage. I'll be happy to just run things off the currently installed power points.

I'm definitely going ahead with this construction so it's just a matter of more learning about the most effective isolation design and working
towards that financially.

I will be building this myself with the aid of my father so labour costs won't be an issue as I'm happy to exploit him.

When you say beefing up the outer leaf/metal shell, would this be a case of attaching large amounts of acoustic insulation material?

I was rightly or wrongly imagining I'd have to line it all with a certain width of insulation, then leave a certain gap between this and the exterior part of the constructed room
(with exposed acoustic insulation on external side).

Regardless of the costs involved, am I naive in thinking this will provide an adequate level of sound insulation?

I live in a reasonably remote area and don't have heaps of neighbours so don't need absolute silence outside, just a significant reduction in volume.

I failed to mention there's already electricity connected with a lot of points around the garage. I'll be happy to just run things off the currently installed power points.

Right, but after you build the inner-leaf, all of those will be inaccessible, on the other side of the wall...

I'm definitely going ahead with this construction so it's just a matter of more learning about the most effective isolation design and working towards that financially.

I'd suggest two books: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. The first one is great for learning about the principles of acoustics, and the second one is great for learning about how to actually design and build a studio, in terms of the construction materials, techniques and tools that you will need.

When you say beefing up the outer leaf/metal shell, would this be a case of attaching large amounts of acoustic insulation material?

Not really, no. Acoustic insulation, such as foam. mineral wool, and fiberglass, do not stop sound. They just absorb some of the energy as it passes through, but that's not the same thing. It's a bit hard to get your head around this concept at first, but absorbing sound is very different.

Think of it this way: if you need to mop up some water that spilled in places you didn't want it in your kitchen, then a sponge is a great way of doing that. It just soaks up the water, really well. But if you turn on the tap and hold the sponge across the end of the tap, the sponge does nothing at all to stop the water flowing through. The same with acoustic absorption: it's great for mopping up sound that is going some place you don't want it (treatment) but lousy at stopping sound from getting out of the building (isolation).

To stop water flowing out your tap, you need something solid and massive, and it needs to seal up tight against the tap. Ditto for sound: To stop sound, you need mass and hermetic seals. "Mass" means heavy, and "hermetic seal" means air-tight. No gaps. Not even the slightest tiny crack.

So "beefing up your wall" means adding a lot of mass to them, with some type of heavy construction material, such as drywall (= gypsum board, = plaster board, = sheetrock), or OSB, MDF, plywood, fiber-cement board, or similar panels that are heavy. And you need to attach them in such a way that the joints between them are seamlessly air-tight, all around the room.

I'm not sure if it is feasible to do that to your existing structure, for two reasons: 1) How would you attach that to the thin steel skin on your shed? 2) Can the structure safely support the huge additional weight that you'd be hanging from it? I suspect that the answer to #2 is "no", and to #1 is "can't be done easily".

That leaves you with the only other feasible option: build another isolation wall just inside that one. In this case, you would end up with a 3-leaf wall, instead of the much more desirable 2-leaf wall, but sometimes that is the only solution.

Regardless of the costs involved, am I naive in thinking this will provide an adequate level of sound insulation?

For the same reason I outlined above, that would not work. Absorption does not stop sound, any more than a sponge stops water.

I live in a reasonably remote area and don't have heaps of neighbours so don't need absolute silence outside, just a significant reduction in volume.

That is certainly possible, but you do need to put numbers to it. "significant reduction" is not something you can plug into the equations that help you figure out how to build your walls. You need a real-world number, such as 40 dB reduction, or 60 dB reduction, or 50 dB, or whatever it is you decide on. You can figure that out with a simple hand-held sound level meter.

- Stuart -

Thanks heaps Stuart.

Your analogies are great and have helped me under stand what needs to happen.

I will do some more research and check out those books. Hopefully I can run my plan by you soon.

Hi again Stuart.

I've commenced sealing in every single gap of shed interior/exterior with sealer in preparation for adding a layer of acoustic insulation batts.
I'll then be sealing that in to the shed interior wall with a drywall wall, mounted onto the insulation layer/shed interior.

Just wondering if I should add a layer of insulation on the outer drywall layer?

That would mean outer side of leaf 1 would face onto outer side of leaf 2, both lined with insulation.
Wondering if the extra layer in red (see image) would make enough of a difference in overall exterior sound reduction to warrant doing?

Hi there, just wondering if anyone could let me know about my question above.

Wondering if it's worth adding in this extra layer? Will the reduced depth of air gap have a negative effect higher than any positive effect an extra layer of insulation will achieve?

wondering if I should add a layer of insulation on the outer drywall layer?

Yes, definitely! Fill the entire cavity as much as you can. That insulation acts as the "damper" on acoustic resonance and other stuff inside the cavity, and is very necessary. Make it as thick as you can. The density of the insulation should be about 50 kg/m3 if you use mineral wool, or about 30 kg/m3 if you use fiberglass.

Will the reduced depth of air gap have a negative effect higher than any positive effect an extra layer of insulation will achieve?

Insulation does not reduce the air gap: Insulation is mostly air in any case... In fact, due to technical reasons, the air gap actually "seems" bigger to sound waves moving through it when you put insulation in there. It appears to be about 1.4 times as big...

- Stuart -