Setup of a Homestudio for Digital Music Production

Hi guys, this is my first post and I am really glad to have found this great forum. I am planing to setup a room in my flat for digital music productions and I would like to obtain semi-professional results in the near future (hopefully). I digged into some literature and tutorials but think I now should ask the pros how to avoid mistakes as much as posible from the beginning on. The goal is to obtain a representative, neutral sounding picture of what I am composing and mixing. For nearfield monitoring I am using a pair of M-Audio's BX-8 D2. There are two alternative rooms available to setup the studio. A large room, which I would prefer and an alternative small room, which in my opinion might be to small and not suitable. But maybe you can give me advice. All walls in both rooms are made of brick, covered with mortar and woodchip wallpaper. The ceiling is made of gypsum-plates, attaached to wooden beams and covered with woodchip wallpaper too. The floors are pitch-pine piling. I attached pictures to illustrate how I would setup the studio to my best current knowledge und intuition and where to place elements to improve the acoustics (red). Not shown for clarity is a screen placed at the ceiling and tilted by 12° to avoid reflections into the sweet spot. As I am pretty unsure about this configuration, where to place absorbers and diffusors and not to overkill, I would appreciate any comment on the following questions to avoid bad decisions and mistakes during purchase and construction. Since I am living for rent, I would like to avoid installations which permanently alter the room or which are hard to remove. My budget is currently at 1000 USD and must not exceede 1300 USD. 1. Are the spots where I intend to place absorbers reasonably chosen? 2. At which places diffusors should be installed? 3. Which type of absorbers and diffusors would be recommended for my budget and the give room situation? (commercial solution vs. DIY?) 4. Could the smaller of the two rooms (see pictures) be more easily optimized with the given budget? 5. How critical would be the small wall-distance of the speakers in the small room or the alignment of the work-spot along the shorter axis of the room? Hopefully my description is accurate enough and I would be glad to receive any tips or recommendations on the current setup. Cheers, Matthias

Hi Matthias, and Welcome! :)

For nearfield monitoring I am using a pair of M-Audio's BX-8 D2.

Those are rear-ported, which pretty much rules out soffit mounting, so they'll have to go on speaker stands, as you show in your proposed layouts. The stands must be massive (very heavy), and the speakers should be decoupled form the stands with a layer of Sorbathane rubber, or something similar.

Not shown for clarity is a screen placed at the ceiling and tilted by 12° to avoid reflections into the sweet spot.

That probably will not prevent reflections, but it will help with flutter echo and probably also with some modal problems: And if you put a thick layer of absorption on that panel (at least 10cm) then you'll be dealing with the reflections too. Built like that, it is normally called a "hard-backed ceiling cloud", and that's a good idea.

As I am pretty unsure about this configuration, where to place absorbers and diffusors and not to overkill,

Both of those rooms are too small to be able to use most types of diffusers. Your only options for treatment are absorption and controlled reflections.

There are two alternative rooms available to setup the studio.

I would definitely use the large room, not the small room, for many reasons. However, I would turn the layout around 180°, so you are facing the window, not the closet. That closet is going to cause you LOTS of problems if the room faces it, so your only real option is to face the window. If you do that (face the window) then your speakers should go right up against that wall/window, and you should have a thick panel of absorption between the wall and the speaker. The rest of your "option #1" would then be more or less correct, except that you need to make the corner bass traps much bigger: at least 60cm across the front face (the diagonal). You could then take everything out of the closet, take off the doors, and fill the entire closet with absorption, for a really nice rear bass trap wall.

3. Which type of absorbers and diffusors would be recommended for my budget and the give room situation? (commercial solution vs. DIY?)

Forget diffusers: the room is too small for that. You can build your own absorbers using something like Owens Corning OC-703 semi-rigid fiberglass. Make a wooden from to hold it in place, cover the frame in cloth, and you have a really good, inexpensive absorber.

4. Could the smaller of the two rooms (see pictures) be more easily optimized with the given budget?

If you take out that closet completely, just leaving a blank wall, then it might be a possibility. But since it is even smaller, it will need even more bass trapping than the larger room, so it might actually cost you more to treat the small room. I think the large one is better.

5. How critical would be the small wall-distance of the speakers in the small room or the alignment of the work-spot along the shorter axis of the room?

OK, this gets a bit complex. the minimum distance from speaker to front wall depends on the speaker itself: What is the lowest frequency that it can produce? The round-trip distance must be GREATER than the half-wave length of the lowest frequency. If not, you will get cancellation at that frequency, due to the reflected wave being exactly out of phase with the direct wave. The manual for your speaker says that it goes down 38Hz, but in reality it will still produce sounds lower than that. Call it 34 Hz., for the sake of argument and easy math. The wavelength for 34 Hz is roughly ten meters. Half wave is 5 m, so the speaker must be at least 2.5m away form the front wall. Your room is obviously too small for that. You cannot get your speakers far enough away from the front wall to avoid SBIR. So you need to go with "Plan B": put them as close to the wall as you can get them, with a thick panel of absorption in between. So turn your room around, re-do the design based on your original "Studio3D_1.jpg", modified, as above, and post the result here so we can take another look at it. - Stuart -

Hi Stuart, thank you very much for you detailed an extremely helpful comment. I modified my design accordingly and comment on your suggestions below. I decided to use the large room for setup.

Hi Matthias, and Welcome! :)

For nearfield monitoring I am using a pair of M-Audio's BX-8 D2.

Those are rear-ported, which pretty much rules out soffit mounting, so they'll have to go on speaker stands, as you show in your proposed layouts. The stands must be massive (very heavy), and the speakers should be decoupled form the stands with a layer of Sorbathane rubber, or something similar.

My current stands are decoupled from the speakers by a rubber foam sheet of 3 mm thickness (delivered with the stands). If I think of something more "heavy", I would test a thick rubber sheet used to decouple washers from the ground. I will also try to add weight to the stands, or - if this doesnt work out well - try to build something massive from scratch.

Not shown for clarity is a screen placed at the ceiling and tilted by 12° to avoid reflections into the sweet spot.

That probably will not prevent reflections, but it will help with flutter echo and probably also with some modal problems: And if you put a thick layer of absorption on that panel (at least 10cm) then you'll be dealing with the reflections too. Built like that, it is normally called a "hard-backed ceiling cloud", and that's a good idea.

I will try that! My intention is to use 10 cm thick basotect acoustic foam or so called thermarock wool for all absorbers at the walls and the ceiling to obtain the desired absorption to attenuate the first reflections both at the sweet spot and the couch for listeners.

As I am pretty unsure about this configuration, where to place absorbers and diffusors and not to overkill,

Both of those rooms are too small to be able to use most types of diffusers. Your only options for treatment are absorption and controlled reflections.

I will try to figure out the number and right placement of absorbers using a mic (Behringer ECM8000) and software (Room EQ Wizard) to check for energy time curves and reverbation times and would try to get down to 0.3-0.4 s reverbation time especially for low frequencies without killing higher frequencies.

There are two alternative rooms available to setup the studio.

I would definitely use the large room, not the small room, for many reasons. However, I would turn the layout around 180°, so you are facing the window, not the closet. That closet is going to cause you LOTS of problems if the room faces it, so your only real option is to face the window.

I flipped the design to face the window now. Even though not really desired by my housemate, I will move the closet out and place an absorber at that spot. The closet cannot be used as a basstrap as there is opposition from my housemate. :)

If you do that (face the window) then your speakers should go right up against that wall/window, and you should have a thick panel of absorption between the wall and the speaker. The rest of your "option #1" would then be more or less correct, except that you need to make the corner bass traps much bigger: at least 60cm across the front face (the diagonal). You could then take everything out of the closet, take off the doors, and fill the entire closet with absorption, for a really nice rear bass trap wall.

Two room-height bass traps with the dimensions 285x62x28 cm (HxWxD) will go into each corner of the room to treat the modes as good as possible. The speakers would be shielded from the window and frontwall mostly by two additional basstraps of this dimension. The frontside cannot be fully covered as I am afraid to get fungi problems. However, the window front will be shielded by a 10 cm thick absorber.

3. Which type of absorbers and diffusors would be recommended for my budget and the give room situation? (commercial solution vs. DIY?)

Forget diffusers: the room is too small for that. You can build your own absorbers using something like Owens Corning OC-703 semi-rigid fiberglass. Make a wooden from to hold it in place, cover the frame in cloth, and you have a really good, inexpensive absorber.

I will build all absorbers and bass traps using mineral wool as you suggest. The products locally available are called sonorock or thermarock and are designed for acoustic shielding.

4. Could the smaller of the two rooms (see pictures) be more easily optimized with the given budget?

If you take out that closet completely, just leaving a blank wall, then it might be a possibility. But since it is even smaller, it will need even more bass trapping than the larger room, so it might actually cost you more to treat the small room. I think the large one is better.

Agreed. :)

5. How critical would be the small wall-distance of the speakers in the small room or the alignment of the work-spot along the shorter axis of the room?

OK, this gets a bit complex. the minimum distance from speaker to front wall depends on the speaker itself: What is the lowest frequency that it can produce? The round-trip distance must be GREATER than the half-wave length of the lowest frequency. If not, you will get cancellation at that frequency, due to the reflected wave being exactly out of phase with the direct wave. The manual for your speaker says that it goes down 38Hz, but in reality it will still produce sounds lower than that. Call it 34 Hz., for the sake of argument and easy math. The wavelength for 34 Hz is roughly ten meters. Half wave is 5 m, so the speaker must be at least 2.5m away form the front wall. Your room is obviously too small for that. You cannot get your speakers far enough away from the front wall to avoid SBIR. So you need to go with "Plan B": put them as close to the wall as you can get them, with a thick panel of absorption in between.-

I hope that the plenty of absorptive material between the speakers and the wall now attenuates SBIR or dampens it to accepable levels.

So turn your room around, re-do the design based on your original "Studio3D_1.jpg", modified, as above, and post the result here so we can take another look at it.-

I attached the new design (and for information a photoraph of the window front wall) and am really looking forward to further suggestions. Or maybe a Go! for starting construction. :) Many thanks again! Matthias

That layout makes a lot more sense!

My current stands are decoupled from the speakers by a rubber foam sheet of 3 mm thickness (delivered with the stands). If I think of something more "heavy", I would test a thick rubber sheet used to decouple washers from the ground.

If the 3mm sheet came with the stands, and they are good quality, then you should be OK. "Heavier" rubber will probably not be useful: isolation depends on correct deflection if the rubber under the weight of the speaker, and heavy rubber will probably be too stiff, and will not deflect enough.

I will try to figure out the number and right placement of absorbers using a mic (Behringer ECM8000) and software (Room EQ Wizard) to check for energy time curves and reverbation times and would try to get down to 0.3-0.4 s reverbation time especially for low frequencies without killing higher frequencies.

It's not really reverb time that you are measuring. Small rooms do not have statistically valid reverberant fields for the lower part of the spectrum. Rooms have to be quite large to have a statistical reverb field. What you are actually measuring is modal response. If you measure correctly with REW, then the modes should be fairly obvious on the graphs.

However, the window front will be shielded by a 10 cm thick absorber.

You probably don't need to cover the glass. You seem to have good bass trapping in the corners and absorption on the sides, and the glass is well out of the area that could cause you first reflection problems, so you could leave the glass clear, and have natural daylight coming in, if you want to. If you already have that absorber, then put it on the back wall instead, as well as the other absorber you show there. The back wall will need plenty of absorption. You might need to cover the front of your bass traps with plastic, to prevent them from taking out too much of the high frequencies. REW will show you if you need to do that. You should also put plastic under your cloud absorber, to prevent the fine particles from coming loose and filtering down onto your equipment over time. But don't cover the side panels or the panel on the rear wall.

and am really looking forward to further suggestions. Or maybe a Go! for starting construction.

Looks good to me! I say "Go!" :) - Stuart -