Small mixing/recording room design - Singapore

Hi everyone, I'm a producer in Singapore doing mostly electronic (programmed) music (pop, R&B, synth-dance) for various major labels (Warner, Universal, etc). I just got an apartment and am planning to build a studio in what was formally a bedroom in the apartment. My goals are to create a small but cosy and welcoming space for me to record and mix music in. I expect mostly vocal and solo instrument recording, and I do mostly Control Room recording, but a vocal booth might be helpful to provide options. In terms of aesthetics I'm aiming for a place that's not overly expensive, but still conveys an authoritative but friendly vibe to major-label artists that may pop by. Loudness-wise, I normally mix at or below 85 dB. There are no shared walls with neighbors, just shared ceilings and floors (it's an apartment on the 7th floor) and I don't foresee isolation being a huge issue. Walls seem to be the standard drywall-on-both-sides-of-framing deal, but again, isolation is not a huge priority. Dimensions of control room: 11.6 x 14.4 x 9.1 feet Dimensions of vocal booth: 7.9 x 4.8 x 9.1 feet Here is the JPG of a design I've come up with, to the dimensions of the room, with some help from Sayers' stock design online... Here's a SketchUp model from my website Some clarifications: a door to the right of the singer (not visible from this angle) leads directly to an attached bathroom. The door to the left of the singer is currently an open doorway but that's due to my SketchUp n00bness - if it's meant to be a vocal booth there will be a solid core insulated door there. Budget is about USD7-10k. Questions: 1) The vocal booth is currently a walk-in closet. I haven't put in any acoustic treatment in the graphic yet, but I am aware that small rooms need to be treated like crazy. Given the dimensions of the booth, is it even worth constructing a booth? Or should I just maintain it as a closet and go fully with the control room recording idea? 2) For the Slot Resonators, I've seen the webpage on John's design, but I can't really make sense of it. What does "gaps alternating between xx-yy mm" mean? What intervals do you increase the gaps at, or is that arbitrary? For example, if the first gap is 5 mm, do you use 7 or 8 mm for the next gap? I'm interested in broadband absorption, obviously, so does anyone have a completed plan for a resonator of say 9ft in height? 3) Will this design work, acoustically? I've put the seat at roughly the 38% position with respect to the front wall, not where the acoustic treatment ends (that's correct, right?) BTW, I'm planning to put in a cloud as well, but it's not represented in the file. 3a) Is this room in conformance to all that Golden Ratio mumbo jumbo? :) Thanks guys for all the help. Please forgive me if I've inadvertently missed out on something in the pretty long list of requirements! :) Looking forward to your brutally honest feedback and comments.

Hi Tat! Welcome!!!

Dimensions of control room: 11.6 x 14.4 x 9.1 feet

According to Bob Gold's calculator, that isn't too bad as a ratio. It works out to 1 : 1.26 : 1.57, which is really close to "C. P. Boner0s ratio" of 1 : 1.26 : 1.587. There are about a dozen isolated modes, all between 40 an 100 Hz (roughly), but overall it looks reasonable. However, I'm assuming that those are the dimensions you'll be STARTING with, not necessarily the final inner-leaf dimensions? (Assuming you do decide to do some isolation).

Here is the JPG of a design I've come up with,

A couple of comments (in no particular order...): 1) I guess that's just a rough draft, not the final complete plan? 2) I'm wondering about those "holes" in the front corners, in the middle of the bass traps. Is there a reason for those, or do you plan to fix that? 3) I see you are not planning to soffit-mount your speakers: Any reason for that? You seem to have the space and budget to do it, and the benefits would be excellent. 4) Left rear corner: Is that a window of some kind? Can you get rid of it? It is in the exact location where you a bass trap should go. 5) ...

Given the dimensions of the booth, is it even worth constructing a booth?

I reckon that it is a reasonable size: I've seen smaller! But you'll need to modify the shape, and isolate it better, if you want to use it seriously as a booth. You should probably think about angling at least two of the walls to get away from parallel, plus plan on isolating it from both the CR and the rest of the building. That might take up a lot of space.... Is the wall between the CR and booth movable? I mean, could it be knokced down and re-built in a slightly different location? 6) ...

What does "gaps alternating between xx-yy mm" mean? What intervals do you increase the gaps at, or is that arbitrary?

It means what it says! You don't VARY randomly/arbitrarily between the two numbers, you ALTERNATE between the two numbers. So one gap will be XX, the next will be YY, the following will be XX again, etc. 7) ...

I'm interested in broadband absorption, obviously, so does anyone have a completed plan for a resonator of say 9ft in height?

For broadband, angle the entire structure away form the wall behind it. The resonance and Q depend on the depth behind the slot, and also the absorption in the cavity: Follow John's plans, and take a close look at how he has implemented those slot walls in several of his designs. 8) ...

Will this design work, acoustically? I've put the seat at roughly the 38% position with respect to the front wall, not where the acoustic treatment ends (that's correct, right?)

It looks like a good start on a design. With some tweaking it should be great, I reckon. 9) ...

Is this room in conformance to all that Golden Ratio mumbo jumbo?

Well, it's not a "golden ratio", but it is really close to a known good ratio, so you should be fine on that front... But once again, you need to work with the ratio for the FINAL inner-leaf surfaces, not necessarily the ones you have now.

Looking forward to your brutally honest feedback and comments.

Yep, we sure can do that! "Brutally honest" is what we do best! :) - Stuart -

One thing though... Your room ratio should be based on the outer - heavy, rigid, Low Frequency containment shell. If your walls are gypsum then you will have fewer VLF issues as they pass the very lows and absorb LF up to a point. Ratios are very important to consider in the design stage as they will affect the ultimate outcome of the design. With your proposed room and the dimensions given, like Stuart said, has a fairly even spread and you won't have any near doubles in the modal patterns until about 195Hz (I wouldn't worry about it). You should focus your trapping from 40Hz to 180Hz. Note that in a small room it is very easy to create a dead environment with trapping. Be prepared to do some testing... The idea of all the trapping is to control the LF decay (not RT-60) to a point where it matches the decay of the mid and HF - so the response is uniform. Cheers, John

"Your room ratio should be based on the outer - heavy, rigid, Low Frequency containment shell. If your walls are gypsum then you will have fewer VLF issues as they pass the very lows and absorb LF up to a point." Please explain this in terms that anyone reading with a sixth grade education can understand. It reads like Philip Newell...

It doesn't seem to be talking about MSM theory, either...

I want to say that there is mention in MHBOA (Everest) of something that may allude to this...but Mr. Everest may be( excluding Eric) the only one that can decipher those minute mathematical details in the hopes of making this a reality.

xSpace wrote:

Please explain this in terms that anyone reading with a sixth grade education can understand. It reads like Philip Newell...

Hahaha! Sorry! Well, picture the low frequencies as water waves. If the barrier is thin and the waves can move it, the wave will continue on through the medium until it strikes a surface that does not move. At that point it will loose a small amount of energy and re-radiate perpendicular to the surface that was struck. Also, for example, a normal bedroom wall with 12mm gypsum board will pass low frequency and at some frequencies act as a panel absorber. If the walls are lined with the standard fluffy pink stuff, the panel absorber becomes more efficient. But a thin interior shell will pass the low frequencies and should not be used in modal calculations. -- By thin interior shell I mean fabric covered insulation, 3mm paneling, drop ceilings, etc... Cheers, John

Your room ratio should be based on the outer - heavy, rigid, Low Frequency containment shell. If your walls are gypsum then you will have fewer VLF issues as they pass the very lows and absorb LF up to a point.

Actually, for MSM construction, the room ratio should be based on the inner leaf, not the outer leaf. In this case, as the original poster explained, there is no "heavy, rigid, Low Frequency containment shell". There is just a simple MSM wall. - Stuart -

Tat, Wow, I'm sorry... just trying to help here. I figured I'd give my help to this forum as well as Gearstlutz. --Don't want to step on toes.. but maybe these 'senior' people can give some hard testing data and quotes from reliable research or at least a polite PM to new people here if they are incorrect instead of (it seems like) a flaming. Anyway, I simply wanted to clarify in case you may had misunderstood:

tattong wrote:

Walls seem to be the standard drywall-on-both-sides-of-framing deal, but again, isolation is not a huge priority.

It's the drywall you want to measure from to calculate your modes. NOT the surface of the inner shell or rock wool, or fabric, or 3mm ply. If that is what is being taught here, it is wrong. -To those posting this nonsense, please provide the research data and AES papers to prove this claim. MSM..? I think they mean Mass - space - mass.

tattong wrote:

1) The vocal booth... Given the dimensions of the booth, is it even worth constructing a booth?

It is definitely worth doing. You will need as much trapping as you can get in there, but I would not recommend splaying walls or any silly nonsense like that when you are already short of space. The canting or splaying of walls does not help modal issues and there are more cost and space effective means to eliminate flutter echo. You can incorporate bass traps in corner polys, checker-board absorption panels to obtain better diffusion, etc...

tattong wrote:

2)I'm interested in broadband absorption, obviously, so does anyone have a completed plan for a resonator of say 9ft in height?

Here's one.. it's easy to build - just plug in your numbers: http://jhbrandt.net/SlatPerfCalc.xls -- Just plug in your numbers in the yellow fields. You can vary the widths and it's broad band!! Place at least 50mm rigid rock wool on the face (right behind the slots) - If you need more info, let me know here so all can benefit.

tattong wrote:

3) Will this design work, acoustically? I've put the seat at roughly the 38% position with respect to the front wall, not where the acoustic treatment ends (that's correct, right?) BTW, I'm planning to put in a cloud as well, but it's not represented in the file.

Yes, Multiply your room length (from drywall to drywall) by 0.38 This is only an ideal starting point - but you don't want to be at like 50% or 25%. ok?

tattong wrote:

3a) Is this room in conformance to all that Golden Ratio mumbo jumbo? :)

It's close. Mind you, the 'golden ratios' devised by Sepmeyer, Louden, Volkmann, & Boner are only starting points. Even the exact ideal ratios at some dimensions become problematic with double and triple incidences. Serious math must be employed to ensure a favorable outcome. Like I said before; you won't have any near doubles in the modal patterns until about 195Hz. and You should focus your trapping from 40Hz to 180Hz. I actually did the calculations. Good luck with your room, Cheers, John

hello john! 1st: welcome :)

jhbrandt wrote:

It's the drywall you want to measure from to calculate your modes.

stuart and you are meaning the same. we're used to say inner leaf and meaning exactly what you said in this quote. MSM also MAM meaning mass - spring - mass mass -air -mass nice to have you here. greetings, carsten

It's the drywall you want to measure from to calculate your modes.

Exactly. The INNER LEAF drywall, not the OUTER LEAF drywall, which is what I understood you to be talking about. Sorry if I misread what you were saying.

NOT the surface of the inner shell or rock wool, or fabric, or 3mm ply.

Huh? What "inner shell" would that be? Sounds like a 3rd leaf to me. Within your inner leaf you will certainly have some treatment of one kind or another, but that should NEVER be built as a shell, and certainly not with "3mm plywood"! You might perhaps use plywood as an element in some type of acoustic treatment, but you certainly don't want another "shell" inside your MSM wall! That would be a third leaf, and would serious reduce isolation at low frequencies.

MSM..? I think they mean Mass - space - mass.

Errr.... no, "they" mean "mass-spring-mass", based on the principle of physics in which it is based. Also often called (less correctly) "MAM" for "mass-air-mass". (Air is a spring, of course.) MSM is the basic principle for getting excellent isolation at reasonably low cost. Maybe you know it by a different name.

I actually did the calculations.

I find it easier to use on-line calculators than to go to all the hassle of doing thousands of calculations by hand. I used Bob Gold's in this case. No big deal. It took about ten seconds to plug in the numbers. 195 Hz is indeed the first frequency where two modes exactly match, but there are numerous others below that (at least 20) where two modes are within less than 1% of each other, starting way down at 62 Hz. (To be more precise, 62.1 Hz is the 0,0,1 axial mode, and 62.5 hz is the 1,1,0 tangential mode.)

You should focus your trapping from 40Hz to 180Hz.

39 to 125, to be more precise (theoretically, of course). But personally, I reckon I'd go for broadband bass trapping, rather than trying to target specific frequencies or ranges. - Stuart -

He means the treatment, soffit fronts, slat walls......

jhbrandt wrote:

Hahaha! Sorry! Well, picture the low frequencies as water waves. If the barrier is thin and the waves can move it, the wave will continue on through the medium until it strikes a surface that does not move. At that point it will loose a small amount of energy and re-radiate perpendicular to the surface that was struck. Also, for example, a normal bedroom wall with 12mm gypsum board will pass low frequency and at some frequencies act as a panel absorber. If the walls are lined with the standard fluffy pink stuff, the panel absorber becomes more efficient. But a thin interior shell will pass the low frequencies and should not be used in modal calculations. -- By thin interior shell I mean fabric covered insulation, 3mm paneling, drop ceilings, etc... Cheers, John

Thank you John. I wasn't asking because I needed an explanation...I was interested in >your< explanation. Looking forward to your contributions at Mr. Sayers forum, Brien

Carsten .. Brien THANKS! Good to be a part of this great site. Cheers, John

Stuart, Sorry we got off on the wrong foot. Let's work together ok? Sincerely, John

Cool by me, John! :) - Stuart -