John Sayers' Recording Studio Design Forum Archive

Hello everyone,
since this is my first post on this Forum, i'd like to introduce myself quickly. I am mixing records for about 6 years now, mostly for local bands and artists. Yet it is just a hobby for me at the moment, doing it mostly for the fun of it. In the near future i will have access to a new(old) Room on top of my flat, which ist going to become a small Home Studio. Since it still is completely cluttered with old stuff, i'll give my best to describe its properties until its decluttered for some actually useful photos.
So the the Room has a base area of roughly 5,7m x 3m. there is a roofslope running along the long side that starts at 2.7m going down to 1m on the other side of the room. So it is quite low there as you probably can imagine.
My Main Questions are:
- which of side will be better to place the desk - the tall side with the slope pointing at my back, or the low side, with the room opening up behind me? the latter one i guess, since that would direct the reflections more away from me, i am not sure though.
- thermal insulation will be added on the tall side of the Room. Would it be viable to just let the insulation open, covering it with an acousticly transparent cloth? or would that be a risk for getting mold? The Walls on their own are dry and realy thick though (50cm of massive rock on the tall side, its an old building). I am aiming for 10-15cm of Rockwool Termarock for its good acoustic properties and value for the money. Yet I fear to overdampen the Room by doing so, is there a thumbrule for reflection/dampening ratios for rough calculations? I do own a calibrated measuring microphone and will provide the data once possible to obtain.
- Would it be useful to just fill up the last meter or so of the low side (which isnt very usable anyways ) with a lighter mineral wool, acting as a 3m x 1m x 1m Basstrap?
What treatment would you suggest for the side walls? one is an Outside wall, with a small window in the middle, the other is yet to be built, probably out of wood & sheetrock. Atm i tend to basic early reflection local treatment?
- how should the ceiling be treated/ does a cloud make sense in my case?
It would be nice if the budget stayed below 1500€ (1700$). Since i enjoy woodworking and my grandpa has a small carpenter workshop, building stuff like membrane absorbers would be an option for me.

Thanks in advance for any kind of advice! I really appreciate that.
Kind Regards,
Dominik

Hi there Dominik, and Welcome to the forum!

- which of side will be better to place the desk - the tall side with the slope pointing at my back, or the low side, with the room opening up behind me? the latter one i guess, since that would direct the reflections more away from me, i am not sure though.

Right! The speakers and desk should be on the low side, with the ceiling rising up behind you.

- thermal insulation will be added on the tall side of the Room. Would it be viable to just let the insulation open, covering it with an acousticly transparent cloth? or would that be a risk for getting mold?

What is the purpose of that insulation? Is it for thermal purposes, or for acoustic purposes? You will need extensive acoustic treatment in that room, and a lot of that treatment will need to go on the rear wall (the one opposite the speakers). That will be almost all absorptive treatment, yes. You will need deep, large bass traps in both rear corners, at the very least. If you use good quality fiberglass or mineral-wool insulation, there should be no problem with mold.

I am aiming for 10-15cm of Rockwool Termarock for its good acoustic properties and value for the money. Yet I fear to overdampen the Room by doing so,

On the rear wall, you will need at least 20 cm thick across the middle part of the wall, and much deeper "superchunk" style bass traps in the corners. Yes, that will also take out some of the higher frequencies too much, but there are ways of dealing with that.

is there a thumbrule for reflection/dampening ratios for rough calculations?

Yes, but it is rather complicated to calculate by hand. USe something like this room mode calculator to figure it out for you:

http://www.bobgolds.com/Mode/RoomModes.htm

I do own a calibrated measuring microphone and will provide the data once possible to obtain.

Before you treat the room, while it is still completely empty, do a complete acoustic test of the room, like this: How to calibrate and use REW to test ant tune your room acoustics. Then do additional tests after you install each piece of treatment, to see how well it is working, and help you decide what to to next.

- Would it be useful to just fill up the last meter or so of the low side (which isnt very usable anyways ) with a lighter mineral wool, acting as a 3m x 1m x 1m Basstrap?

Probably, yes. But please provide a drawing or diagram of the room, and of your proposesd treatment, so we can see what you are planning.

- how should the ceiling be treated/ does a cloud make sense in my case?

The general rule is: "Hard floor, soft ceiling". So the ceiling will need absorption too, but leave the floor hard, solid, and reflective. Yes, clouds are almost always useful in small rooms.

- Stuart -

Hi Stuart,
thanks for your extensive answer!

What is the purpose of that insulation? Is it for thermal purposes, or for acoustic purposes? You will need extensive acoustic treatment in that room, and a lot of that treatment will need to go on the rear wall (the one opposite the speakers).

Both, actually. But primarily for the Acoustic benefits. The need for the high Amount of treatment is to compensate for the low volume of the room i guess? just interested, since i thoght the overall properties shouldnt be too bad, since only 2 walls are parallel (regarding room modes).

On the rear wall, you will need at least 20 cm thick across the middle part of the wall, and much deeper "superchunk" style bass traps in the corners.

20 cm is definitely doable, should it be all Termarock, or is something like 10cm of denser material (eg. Termarock) on the wall, topped by 10cm of some lighter mineral wool better? (thinking of low frequency absorption here). Should the Superchunks go all the way up to the ceiling? their depth will be dependent on particular problem frequencies i guess? or is it just the more the merrier?

Then do additional tests after you install each piece of treatment, to see how well it is working, and help you decide what to to next.

I will, what would the be the right order for that process?

Thanks again! I will draw out something in the evening today, photos will be made once the room is cleared.

Dominik

Both, actually. But primarily for the Acoustic benefits. The need for the high Amount of treatment is to compensate for the low volume of the room i guess? just interested, since i thoght the overall properties shouldnt be too bad, since only 2 walls are parallel (regarding room modes).

Listening volume shouldn't change the type or amount of treatment needed. Having only 2 parallel walls doesn't actually help acoustically as parallel walls that create flutter echos are quite easily addressed. Having an odd shaped room actually makes it harder as you can't accurately predict the modal distribution of said room.

20 cm is definitely doable, should it be all Termarock, or is something like 10cm of denser material (eg. Termarock) on the wall, topped by 10cm of some lighter mineral wool better? (thinking of low frequency absorption here).

I'm not familiar with either product. Gas flow resistivity is the insulation characteristic that really matters. But since most insulation companies are only really concerned with thermal properties, they don't know or document the GFR. So, we can estimate the relationship between GFR and density. Here are those values:

Fibreglass in kg/m^3
High Freq = around 40 (others say 60-80)
Mid Freq = around 35
Low Freq = 20-25

Mineral Wool in kg/m^3
High Freq = around 65 (others say 90-120)
Mid Freq = around 55
Low Freq = around 30 (others say 40-45)

So for your insulation, use these values to determine what product you can get that will treat the correct frequencies.

Having said that, for your rear wall, or superchunks, use an insulation that will work well with low frequencies. You can always easily add a facing to recover mid or high frequencies if they are damped too much.

Should the Superchunks go all the way up to the ceiling? their depth will be dependent on particular problem frequencies i guess? or is it just the more the merrier?

These always should be as big as possible. That means as tall as possible and as wide as possible. More the merrier for sure.

I will, what would the be the right order for that process?

Do an empty room test and then a test after each addition of treatment. Starting with your rear wall would be good start!

Thanks again! I will draw out something in the evening today, photos will be made once the room is cleared.

We prefer your design to be made with SketchUp Make. We all know what we will be looking at and we can guide you through usage if you get stuck doing something like ray tracing. It's free to download and use. To get you started, google and watch some videos on:
- inferencing
- making components
- layers

That should get you going!

Greg

In fact, the extra audio will be evaded much like the electronics





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