Hi everyone, I need some help with acoustical treatment of a very, very small studio I’m building.
Sorry for a very long read, but English is not my native language, and I wasn’t able to make this any shorter.
Please see the attached images, they will make understanding the text easier.
If I should post in studio construction instead of here, let me know.
The room
I have a room that is in a building’s basement. This used to be the place where my band used to rehearse.
Recently my band rented another room in another place and now this place became free and I decided to build a small studio in it.
This room is a bit funny: it’s a triangle, with a height of about 4m.
There are some pipes that run on the CB wall, near the top.
The walls CA and CB are brick and mortar construction and the wall AB is reinforced concrete. The ceiling is reinforced concrete.
Walls CA and CB have the parking garage for my building on the otherside, the ceiling and wall AB have earth on the other side.
Existing acoustical treatment
When we decided to start rehearsing there, we built a bunch of diy acoustical treatment using rockwool (70kg/m3 density, for comparison, owens corning 703 has 45kg/m3) density), burlap and wood:
We built three bass traps, all using a total thickness of rockwool of 80mm (two panels thick).
- A bass trap straddling corner A – this goes from top to bottom, with a width of 600mm (one panel wide).
- A bass trap straddling corner B – this goes from top to about half of the height of the room, because otherwise it would collide with the pipes, and is also one panel wide
- 3 basstraps of 1200mmx1200mm straddling the ceiling-wall corner on the CB wall, serving as baffle against the pipes also.
These I am leaving on the room as they are bolted to the wall and would be much of a fuss to take out (and are doing a good job).
We also hung on the walls absorption panels, made with a wood frame, where half of the thickness is wool and the other half is air.
We used 20mm thick rockwool sheets, and made 5 double sheet traps (40mm air, 40mm wool) and 5 single sheet traps (20mm wool, 20mm air).
These I took out and plan to re-use on the new tracking room.
Dividing the space into two rooms
Using sketchup and patience and moving stuff around in real life, I arrived to the following layout.
We are currently building the wooden frame for it.
Basically I am installing a wall and a ceiling and making a control room and a tracking room.
The interior height of the control room is 2,25m.
The new all only goes up to this height as I thought it would be beneficial to keep as much volume on the tracking room as possible.
The new walls and ceiling are double and never touch each other (though they are ‘coupled’ by being bolted to the existing floor and walls).
The wall is made of a drywall of 13mm, then 40mm of the same rockwool described above, then about 15mm air gap and then 40mm of rockwool and 13mm drywall again.
The ceiling is also double, with the same construction and the ‘outer leaf’ never touches the ‘inner leaf’.
The door is a standard bought door, that I plan on adding more mass with a synthetic foam panel (not that egg crate/pyramide type stuff, it’s a thing they use on construction I can’t explain in English. I installed this on the existing room door and it helps isolation through door). I also will had some self adhesive rubber strips that make the seal of the door airtight.
There is also a window. The window is made of two acrylic 15mm sheets, that mount flush with the drywall and have caulk and a wooden frame on top.
What do you guys think? Would the isolation between control room and tracking room be ok?
From outside of the room, will people in the parking garage hear considerably less?
Acoustical treatment of the control room, help needed.
I need some help figuring out acoustical treatment:
On the tracking room I already have the fixed bass traps, and will be re-hanging 8 of the 10 panels I had from before, 2 of each kind on wall AB and two of each kind on wall CB.
I’ll add a carpet on the ground and I think I am pretty much covered here.
On the control room however, I am hesitant. Here is what I’m thinking about:
- Cloud above listening position, 2 panels thick, on an angle from the ceiling. Would it be worth it to make it flush with the ceiling walls and make it a sort of bass trap, or could I make its border be offset by about 10cm of the walls?
- Bass trap on CA wall, on wall ceiling angle. This would be about 2m long, and would be on panels width on the front and then filled in on the inside with less dense fluffy rock wool (10kg/m3 it’s half price right now at my ‘home depot type’ store). What do you think?
- The window will be highly reflective so I thought of putting thick curtains over it. This would allow me to use the window to see the artist while tracking, and close the drapes to mix. For symmetry’s sake I would also install curtains on the left side angle wall (AB).
- On the back wall, would a diffuser help, or should more absorption be in order? Of what kind? What would you do?
Please give me all the input you can think might help, as I’m a bit lost here.
Thanks in advance, and if you somehow managed to read this far I’m very grateful!
Help with acoustical treatment of small weird room
Originally posted at johnlsayers.com, topic 19483.
Sorry forgot to name the corners!
it's like this:
A
| \
C--B
Hi there "menosum". Welcome.
Please read the forum rules for posting (click here). You seem to be missing a couple of things! :)
- Stuart -
Hi Stuart, thanks for your help.
I already added my location (Lisbon, Portugal) to my profile.
I don't think I'm missing any other information... Is everything OK?
If not just let me know and I'll do my best, thanks!
if you are building a new studio then you must be installing soundproofing foam and panels. I would like to recommend you [SPAM DELETED] company as they are offering [SPAM DELETED] on acoustic products. you just need to like their page on facebook.
Visit website [SPAM DELETED]
No you should not, because there is no such thing as "soundproof foam". I already delete the spammer and banned him permanently for violating the forum rules, but I added this reply just in case anybody was confused by his snake-oil pitch. Anybody who talks about "soundproof foam" doesn't have a clue about acoustics to start with, and one has to wonder why a reputable company selling real acoustic products would need "likes" on a facebook page... :shock: - Stuart -if you are building a new studio then you must be installing soundproofing foam
Hi again "menosum". It looks like I completely missed your reply! Sorry about that! I only noticed your thread again because of the spammer trying to butt in on the forum with his silly hype for "soundproof foam" ( :) ), so from that point of view, you can thank him for bringing attention to your thread! (Just not for his spam... )
That's fine, and no problem at all! Long is better, as it provides a lot more detail. And your English is a hell of lot better than my Portuguese! :shock:Sorry for a very long read, but English is not my native language, and I wasn’t able to make this any shorter.
Triangles are complicated, but 4m of height is good.This room is a bit funny: it’s a triangle, with a height of about 4m.
That's excellent. so you should be getting reasonably good levels of isolation from that (no "soundproof foam" required! 8) :lol: ).The walls CA and CB are brick and mortar construction and the wall AB is reinforced concrete. The ceiling is reinforced concrete.
Even better! That's about the best possible isolation you could hope for, since you have huge amounts of mass and huge amounts of damping on those walls.The ceiling and wall AB have earth on the other side.
That's just a bit on the heavy side. Not too much, so no problem, but something slightly lighter would have been better for low frequency absorption.we built a bunch of diy acoustical treatment using rockwool (70kg/m3 density,
Right, but 703 is fiberglass, not mineral wool, so it has to be less dense in order to provide the correct gas flow resistivity.for comparison, owens corning 703 has 45kg/m3 density
Excellent. That's a good bass trap.- A bass trap straddling corner A – this goes from top to bottom, with a width of 600mm (one panel wide).
Those are fine, and should work well. No need to move them.These I am leaving on the room as they are bolted to the wall and would be much of a fuss to take out (and are doing a good job).
That's already a very small space: do you REALLY need to divide it into two rooms?Dividing the space into two rooms
Then you won't get good isolation! Yes, you do need to bolt them to the floor, but the inner-leaf walls should never be bolted to the outer-leaf walls, or to the outer-leaf ceiling: they can only be attached to each other, and to the inner-leaf ceiling. Nothing else.The new walls and ceiling are double and never touch each other (though they are ‘coupled’ by being bolted to the existing floor and walls).
That's a problem! That sounds like a couple two-leaf wall, basically the same as a house wall. If so, then you wont get much better than about 30 dB of isolation like that.The wall is made of a drywall of 13mm, then 40mm of the same rockwool described above, then about 15mm air gap and then 40mm of rockwool and 13mm drywall again.
I don't understand: Your outer-leaf is concrete. Your inner leaf should be drywall. How can you have a "double ceiling"? If you put up a double ceiling there, with two sets of drywall separate by an air gap, then you have built a TRIPLE leaf ceiling, which is bad. The isolation for triple-leaf is always worse than for double-leaf, all other factors being equal. You should never build triple leaf if you can possibly avoid it.The ceiling is also double, with the same construction and the ‘outer leaf’ never touches the ‘inner leaf’.
Standard doors are usually hollow-core, and that is no use for good isolation. You need a solid-core door.The door is a standard bought door,
That's not the correct way to do it. Foam does not add mass: it adds damping, which you don't need. To add mass, you need to screw and glue additional layers of solid wood to the basic solid core door. The door must end up very, very heavy. You will need to use at least four heavy-duty hinges to hang it, not the usual three light-weight hinges that normal house doors use.I plan on adding more mass with a synthetic foam panel
The type of rubber you use is important. You can't use any old rubber, and weather sealing is also not much use. The best (if you can find it) is Type-K trunk rubber, or you can by proper acoustic sealing products from places like Zero International.I also will had some self adhesive rubber strips that make the seal of the door airtight.
Forget acrylic: it does not have enough mass or rigidity to be useful for studio windows. It is way too light, and way too flexible. You need proper thick glass, and the best type is laminated glass.There is also a window. The window is made of two acrylic 15mm sheets,
That depends on what you mean by "OK", but from my point of view, that will not get you very much isolation. I would estimate maybe 30 dB, maximum. You should be aiming for about a hundred times better than that, at around 50 dB.What do you guys think? Would the isolation between control room and tracking room be ok?
Not really. They will clearly hear your drums, especially the kick and snare. And if you have a bass amp in there, then they will hear that too.From outside of the room, will people in the parking garage hear considerably less?
Carpet is a bad idea for studios: it does the opposite of what you need. Carpet absorbs high frequencies randomly, a little bit of mids, and no lows at all. What you need is something that absorbs a lot of lows, some mids, and no highs! So forget carpet. How many professional studios do you see with carpet on the floor? :)I’ll add a carpet on the ground and I think I am pretty much covered here.
The cloud is excellent, and yest it should be angled, and no it should not be flush. Make it "hard backed" (with a thick wood panel on top, above the insulation) to help control flutter echo and also to break up modal resonance a little.- Cloud above listening position, 2 panels thick, on an angle from the ceiling. Would it be worth it to make it flush with the ceiling walls and make it a sort of bass trap, or could I make its border be offset by about 10cm of the walls?
Very good!- Bass trap on CA wall, on wall ceiling angle. This would be about 2m long, and would be on panels width on the front and then filled in on the inside with less dense fluffy rock wool (10kg/m3 it’s half price right now at my ‘home depot type’ store). What do you think?
You probably do not need anything there over the window, or on the other side: the walls seem to be angled steeply enough so that you will not get first-order reflections at your ears, so you should be OK there. But you will probably need panels above and below the window, since the room is so small!- The window will be highly reflective so I thought of putting thick curtains over it. This would allow me to use the window to see the artist while tracking, and close the drapes to mix. For symmetry’s sake I would also install curtains on the left side angle wall (AB).
The room is way too small for diffusion. The back wall should be very thick absorption, at least 15cm and hopefully more. The control room is way too small, and your head will be located in the worst possible place (modal response, SBIR), so all you can really do in there is to make to pretty dead acoustically. If it is too dead after you treat it, then you can add some broad wooden strips over the insulation, with large gaps between them, but not at locations that would send reflections towards your ears. -- I would suggest that you should re-design your isolation plan first, since there are several problems with it the way you described it. I would also try to make the control room ceiling higher (you said you have 4m there: why limit the height to just 2.25?), so you can have a really thick cloud, plus really thick absorption on the ceiling itself. So please update your design and post it again here, so we can take another look. I promise I'll try to answer much faster this time!!! :) - Stuart -- On the back wall, would a diffuser help, or should more absorption be in order? Of what kind? What would you do?