New studio in Thailand

Greetings from Thailand! After lurking here and on other studio forums for a year and making a lot of designs, I’m ready to post my plans and reveal to the world my ignorance.! We’re getting ready to build our little dream house in suburban Bangkok, in regular meetings with our architect, and the Devil is starting to appear in the details. Problems are exacerbated by differences in local material availability and professional skill sets (to put it tactfully). With apologies for a long post, I’d be very grateful to get some professional opinions to point me in the right direction. About me: I’m a composer, using a lot of computer-controlled equipment for working and to make recordings. I write orchestral and electronic pieces, so I don’t create very high sound levels; 100 dB is exceptional, and I don’t use a subwoofer at this time. Occasionally I record other instruments. The property: The house/studio is going on a corner lot bordered by two quiet streets. We own the lot on a third side (housing a yoga studio), so we have only one neighbor, the back of their house separated by a 2-meter-high wall. And Thais don’t complain much about noisy neighbors. I do need to keep out the sound of a PA horn on the street corner that occasionally blasts out useless announcements (it’s a Thai thing). The house: It will comprise two buildings, resting on separate raised concrete foundations separated by about 3 meters: the house itself, and a combination studio, office/guest room and toilet. Like most Thai buildings, it is made by casting a reinforced concrete frame and filling in walls with brick, covered with concrete. I’ve specified autoclaved aerated concrete (AAC) blocks, rather than the usual cheap clay bricks, because AAC is lighter and has better heat and sound blocking qualities, and because ordinary Thai brick work often leaves many small holes, not always complete filled with mortar, exacerbating the noise and heat problem. The north and south walls, directly exposed to the outside, will be a double layer of 10cm block with staggered seams, while the east and west walls will be a single 15cm layer. Interior concrete walls will most likely be 10cm AAC. The studio: Interior studio dimensions are 542 x 445 cm with a 375 cm ceiling. So the h:w:l room ratio is ~1.00:1.19:1.45. The actual roof is concrete, sloping from 480 to 420 cm, but that can be easily changed. The suspended ceiling is 60x60 cm tiles similar to sheetrock, and the space above will be insulated. Behind the west wall is a space for equipment (a Liebert UPS, several computers and Pro Tools interfaces) and for storage. Originally these were two separate spaces, but I’ve combined them. The floor will be a hardwood laminate over concrete. Bass traps will be made across the “front” (west) wall-ceiling joint, and probably in the corners. Question 1: As it stands, the wall between studio and closets is also concrete block with a heavy door. I wonder it would be better to make the wall with sheetrock on steel studs stuffed with fiberglass, remove the door and use the spaces as bass traps. I guess I’d have to put Owens-Corning 703 or similar on the walls inside. I could fill part of the storage area furthest from the door, but I do need some storage space. Or is it better to keep the wall concrete and do all the treatment within the room proper? Question 2: If the above idea is worthwhile, should the wall be as solid and massive as possible – double sheetrock with Green Glue and properly sealed, or would a flimsier wall work better? Question 3: Would it be better to slope the front part of the ceiling down to say 3 meters, allowing more bass trapping above the ceiling and some deflection of flutter echoes, or is it not worth the trouble? Getting the workers to construct a ceiling like that is not trivial. Hopefully I at least left out anything important. We’re still in the phase where construction details can be altered if necessary. Thanks for your help! John Melcher

Hi John, and welcome to the forum! :)

and the Devil is starting to appear in the details.

Doesn't he always? :) Between him and Murphy, it's surprising that we ever manage to build studios at all!! :shock: :lol:

With apologies for a long post,

Please don't apologize for that ! Wait until you see some of mine.... Long posts are good as far as I'm concerned, because it shows that you put a lot of thought and effort into it. You'd be surprised how many times we get newcomers that post a picture of a crumpled restaurant napkin with a wobbly rectangle drawn on it, and say "Design my room for me here.".... :shock:

I do need to keep out the sound of a PA horn on the street corner that occasionally blasts out useless announcements (it’s a Thai thing)

You'll need to get a level for that: Measure it a few times with a sound level meter, both out in the street close to the source, and also more or less where room will be that you plan to build. That will be a key part of your isolation design. Also measure other noises that could be a problem: thunder, hail, rain, wind, traffic, aircraft, animals, phones, TV, radio, etc.

Like most Thai buildings, it is made by casting a reinforced concrete frame and filling in walls with brick, covered with concrete.

Yup, I'm entirely familiar with that: That's the same way most houses are built here where I live.

Interior concrete walls will most likely be 10cm AAC.

When you say "interior walls", are you talking about proper the inner-leaf of a proper decoupled 2-leaf MSM system?

Interior studio dimensions are 542 x 445 cm with a 375 cm ceiling. So the h:w:l room ratio is ~1.00:1.19:1.45.

Not bad, but it fails one of the critical tests use dby the BBC. take a look on Bob Gold's calculator. http://www.bobgolds.com/Mode/RoomModes.htm You should probably adjust the dimensions a bit, to fix the issue.

Question 1: As it stands, the wall between studio and closets is also concrete block with a heavy door. I wonder it would be better to make the wall with sheetrock on steel studs stuffed with fiberglass, remove the door and use the spaces as bass traps. I guess I’d have to put Owens-Corning 703 or similar on the walls inside. I could fill part of the storage area furthest from the door, but I do need some storage space. Or is it better to keep the wall concrete and do all the treatment within the room proper?

I would go with "Plan B": Wall, doors, and treat the room properly. It doesn't really matter too much how you do that wall, and a couple of layers of drywall on stud frame would be fine, as would concrete. As long as there's a good amount of mass in that wall, you'll be good.

Question 3: Would it be better to slope the front part of the ceiling down to say 3 meters, allowing more bass trapping above the ceiling and some deflection of flutter echoes, or is it not worth the trouble? Getting the workers to construct a ceiling like that is not trivial.

IT can be beneficial to slope your ceiling, but you can achieve pretty much the same thing with a flat ceiling and an angled hard-backed cloud hung below it. That's probably a lot easier to do. Since you aren't doing an RFZ design, it's probably not worth angling the ceiling.

Hopefully I at least left out anything important. We’re still in the phase where construction details can be altered if necessary.

I'm curious as to how you plan to layout that room: Normally, you should have the speakers firing down the longest dimension of the room, and it should be symmetric left/right of the center-line, but I don't see how you can do that with your room, as the doors get in the way. The door at the rear, to the storage area, is not so much of an issue, but the front is: Is there any chance you can re-design that so that the main entry door is in one of the side walls, rather than the front wall? - Stuart -

Thanks very much for your reply!

Interior studio dimensions are 542 x 445 cm with a 375 cm ceiling. So the h:w:l room ratio is ~1.00:1.19:1.45. Not bad, but it fails one of the critical tests used by the BBC. take a look on Bob Gold's calculator.

Actually, I did use that. I started with "Sepmeyer Room A" (1.00:1.14:1.39), which translates to a room 542 x 445 cm, with a 390cm ceiling. It's excellent down to 44 Hz, except for a "yellow" warning at 77.4 Hz. By reducing the ceiling to 375 cm, it's "green" all the way to 38.7 Hz. The proportions are then 1.00:1.18:1.44. I'm not sure what BBC test you're referring to.

Interior concrete walls will most likely be 10cm AAC. When you say "interior walls", are you talking about proper the inner-leaf of a proper decoupled 2-leaf MSM system?

I mean the wall separating the studio from the bathroom.

...would be better to make the wall with sheetrock on steel studs stuffed with fiberglass, remove the door and use the spaces as bass traps. ... Or is it better to keep the wall concrete and do all the treatment within the room proper? I would go with "Plan B": Wall, doors, and treat the room properly. It doesn't really matter too much how you do that wall, and a couple of layers of drywall on stud frame would be fine, as would concrete. As long as there's a good amount of mass in that wall, you'll be good.

I've engaged an acoustic consultant to build bass traps, diffusers, etc. He told me that the closet won't be a good bass trap, regardless of the wall material, but said it would work better if it could move easily. He suggested a wood wall. But this seems to me that by doing this, I'm effectively extending the length of the room for bass frequencies by 160 cm. Bob's calculator says this is still okay but not as good.

I'm curious as to how you plan to layout that room: Normally, you should have the speakers firing down the longest dimension of the room, and it should be symmetric left/right of the center-line, but I don't see how you can do that with your room, as the doors get in the way. The door at the rear, to the storage area, is not so much of an issue, but the front is: Is there any chance you can re-design that so that the main entry door is in one of the side walls, rather than the front wall?

The entrance is in the back of the room. The workstation and speakers will be in front of the wall for the machine room / storage.

I'm not sure what BBC test you're referring to.

It's right there, on the Bob Golds' calculator results: Scroll down until you see the heading "computed information". The third item down is "R. Walker BBC 1996". Under that are three test results, that are either "pass" or "fail": Those are the three tests that the BBC uses for deciding whether or not a room can be used as a control room or critical listening room. If any one of those is a "fail", then the room is rejected. If you click on the heading, it takes you to a technical paper from the EBU that uses the same BBC criteria, and also others.

He suggested a wood wall. But this seems to me that by doing this, I'm effectively extending the length of the room for bass frequencies by 160 cm.

The material itself that you use for building the wall doesn't matter. What matters is the mass. Or more correctly, the surface density of the wall. Walls that have more mass on them will isolate better to lower frequencies. Walls with less mass, won't. There's an equation in physics known as "mass law" which describes this. But you can make up that mass any way you want: concrete, wood, metal, plastic, glass, whatever. Walls having the same surface density will provide the same isolation at the same frequency, regardless of what materials went into them. So for example, a wall with two layers of 5/8" drywall would stop a 200Hz tone just as well as wall made of 7/16" glass, and they would both stop that same tone just as well as a wall made of 1/8" steel plate, or one made of 1/16" lead sheeting, or 1/32" platinum plate. All of those have roughly the same surface density, and according to mass law they would all provide about 27 dB of attenuation for a 200 Hz tone.

I've engaged an acoustic consultant to build bass traps, diffusers

Diffusers? The room is too small to be able to use numeric-sequence based diffusion. According to D'Antonio and Cox (the guys who invented it, and have done extensive work on the mathematical description of how it works), numeric-based diffusion should never be used unless there is at least 10 feet (about 3.1 meters) between the face of the diffuser and the ears of anyone doing critical listening, and for lower frequencies their rule is "3 wavelengths of the frequency one octave down from the lowest cutoff frequency". So for any diffuser tuned lower than about 700 Hz, that distance would be greater than ten feet. And in later research, others have suggested that the number should be seven wavelengths, not three. The reason is simple: up close, diffusers distort the phase, timing, angle and amplitude of the reflected and scattered waves. There are "lobes" around the diffuser at different levels, up close. It takes a while for those distortions to even out and smooth over, and only beyond the 10-foot (or 3-wave, or 7-wave) distance are the smooth enough to not cause problems with the way your brain interprets them. Numeric-based diffusion is only appropriate for large rooms, where there can be plenty of distance between the devices and people's heads. Of course, that doesn't stop people from putting diffusers in small rooms, thinking they look cool and make the room "sound better", but in reality they are not doing themselves any favors. And of course, the manufacturers are in no hurry to tell folks not to buy their products unless the room is large.... :) So for your room, diffusion is not really an option if you want it to be as accurate as possible. Good use of absorption and reflection is all that you need. Yes, if you tweak the room geometry just right, you probably could manage to squeeze in 10 feet between your head at the desk, and the rear wall behind you, but what about your clients sitting on the couch at the back? :) Also, on the bass traps issue: your rear door is right where one of your bass traps needs to go: Bass traps are most effective in corners, but that door is too close to the corner to allow for a suitable sized bass trap, so you might want to consider moving that door further towards the center of the wall. Have you considered doing an RFZ design for your room? - Stuart -

Thanks again! For simplicity sake, I'll break out your ideas into separate replies.

I'm not sure what BBC test you're referring to.

It's right there, on the Bob Golds' calculator results: Scroll down until you see the heading "computed information". The third item down is "R. Walker BBC 1996". Under that are three test results, that are either "pass" or "fail": Those are the three tests that the BBC uses for deciding whether or not a room can be used as a control room or critical listening room. If any one of those is a "fail", then the room is rejected. If you click on the heading, it takes you to a technical paper from the EBU that uses the same BBC criteria, and also others.

Duhh, right in front of me! Interestingly, this "ideal" room mentioned by Everest and others (1.00:1.14:1.39) fails the test: l/h < (4.5w/h - 4). However, if I drop the ceiling yet another 11 cm (542x445x364), it passes, with virtually identical modal response. :) I'm having some trouble grasping exactly what that term represents, so I'll take the BBC's word for it. But what happens if the ceiling is sloped? I was told it should be at least 15 degrees. If it slopes down from back (by the entrance door) to front by the storage machine rooms it would drop 145 cm (tan 15 deg. =.268), or from 364 to only 219 cm. Or should the "ideal" height (364cm) be in the middle, or the front of the room instead? Personally, I'm inclined to keep the ceiling constant and hang an angled cloud.

He suggested a wood wall. But this seems to me that by doing this, I'm effectively extending the length of the room for bass frequencies by 160 cm.

The material itself that you use for building the wall doesn't matter. What matters is the mass. Or more correctly, the surface density of the wall. Walls that have more mass on them will isolate better to lower frequencies.

I'm not trying to isolate bass frequencies, am I? The space behind this wall is just storage, and the only noise is from equipment fans. The original design had a concrete block wall and a heavy wooden door. Then I started thinking, if the wall were more flexible, the door were removed, and absorbant material put on the closet walls, it might serve somewhat as a bass trap. On the other hand, if bass passes through to the outer walls before being reflected, the room dimensions are essentially changed; the length becomes 702 cm. A main consideration is ergonomic. A drawback of using so many computers is dealing with crashes and otherwise having to go into the machine room several times a day. Taking the door off makes it a lot easier, but I don't want to create a resonant chamber. I'm inclined to go back to the original design with a concrete wall (less resonance, and much cheaper) and a door.

The room is too small to be able to use numeric-sequence based diffusion ... numeric-based diffusion should never be used unless there is at least 10 feet (about 3.1 meters) between the face of the diffuser and the ears of anyone doing critical listening, and for lower frequencies their rule is "3 wavelengths of the frequency one octave down from the lowest cutoff frequency". So for any diffuser tuned lower than about 700 Hz, that distance would be greater than ten feet ... So for your room, diffusion is not really an option if you want it to be as accurate as possible. Good use of absorption and reflection is all that you need ... Yes, if you tweak the room geometry just right, you probably could manage to squeeze in 10 feet between your head at the desk, and the rear wall behind you, but what about your clients sitting on the couch at the back?

If I position my head at the "38% point" away from the front wall, the distance to the back wall is .62 x 542 = 336 cm = 11 feet. It's a personal studio, so there are no clients, nor any couch. The back of the room might be used for instrument recording occasionally.

Also, on the bass traps issue: your rear door is right where one of your bass traps needs to go: Bass traps are most effective in corners, but that door is too close to the corner to allow for a suitable sized bass trap, so you might want to consider moving that door further towards the center of the wall.

I was planning to use all the space between ceiling and roof as a trap, plus across the back "corner" between wall and ceiling. There is also space at the front corners. The corner you referred to is actually about a meter from wall to door, so I could squeeze one in. To move the door further requires changing the bathroom configuration - possible, but just barely.

Have you considered doing an RFZ design for your room

I did - the original design was a 9-sided room, which I ruled out partly because of cost, but mainly out of fear the local builders would make a mess of things. I was planning to hang "Abflector" type reflective surfaces on the side walls and ceiling near the mixing position.

Hi John, I live in Thailand too. :D I'm Musician/Audio engineer graduated from SAE. Actually I'm Recording/mixing engineer but I've learned some Basic Acoustic at SAE and reading few Books about Acoustic. I'm not an expert but I'd like to ask stuart some question and share my opinion. I believe Stuart will correct me If I make any mistake. :lol:

I did - the original design was a 9-sided room, which I ruled out partly because of cost, but mainly out of fear the local builders would make a mess of things. I was planning to hang "Abflector" type reflective surfaces on the side walls and ceiling near the mixing position.

local builder are OK but you have to check everything don't let them do it on their own. Get them a good Table saw will help them cut accurate angle easily. To keep out sound of PA horn. I think you have to build decoupled drywall anyway. So building RFZ should cost you the same as building decoupled wall. My architect (The one I'm working with right now) told me cost of dry wall (12mm gypsum without insulation) is 300 Baht/Meters ² (I think building cost is included because 12mm gypsum only 1xx Baht per sheet) Rockwool 40kg/m3 60x120x5cm 150 Baht per sheet that's about 200 Baht/Meters ² let say it's about 800 baht/Meters ² for 2 layers of 12mm gypsum wall with 2" insulation or 500 baht for single layer of 12mm gypsum wall with 2" insulation I roughly design RFZ and pull it up 3m it's SUM area of drywall and ceiling surfaces are 81Meters ². So, building should cost you around 64,800 Baht for 2 layers and 45,000.- for single layer I've check Ray tracing Blue area is Refection Free Zone. If you'd like to get more area just Splat side walls wider. So you can sit closer to Acoustic axis crossing point (I'm not sure that "Is it ok to sit this far from crossing point" :oops: .)

Soundman2020 wrote:

Also, on the bass traps issue: your rear door is right where one of your bass traps needs to go: Bass traps are most effective in corners, but that door is too close to the corner to allow for a suitable sized bass trap, so you might want to consider moving that door further towards the center of the wall.

About Bass trap at Bottom Right corner. I think it is impossible to move that door. Can't we ignore it? I saw some of John Sayers's design do that such as: Thai Architect always put doors in corner and I see something like this all the time. is it OK to do like what I draw or like John did?

If I've engaged an acoustic consultant to build bass traps, diffusers

Many studios in this country were designed to use diffuser wrongly by person who doesn't have true knowledge. Most of them were built long time ago. Back in those day we don't really know much about audio engineering and acoustic. So, Their are many small studio with diffuser and when newbie acoustic consultant/designer see those studio make them think that diffuser is OK to use in small studio (and I was one of them :oops: ). I didn't notice this until I discuss with Stuart about diffuser last year. He mentioned "Cox said..." So, I've checked in a book called "Acoustic Absorbers and Diffusers: Theory, Design and Application by Trevor J. Cox and Peter D'Antonio" So, Stuart is right. Sorry If some parts don't make any sense because of my English :oops: Ken

Hi Ken, Thanks for your post! It's great to get a local perspective. The PA is becoming more than just a studio problem and may require a drastic solution. Actually, I don't think it will penetrate the concrete studio walls, especially since it's in the back of the building complex, with several walls in between. But it's going to be a nuisance when I'm NOT in the studio. They hired a lady - a friend of the village council I think - and she sees it as her little radio station, and the more noise she makes, the better she is doing her job. I also suspect that someone on the council got a kickback for buying the PA (they put it in just 2-3 years ago). Today is quiet so far, but yesterday there were 5 separate announcements, each followed by a minute of old Thai music, loud & distorted. For the cost of building double walls, I could probably bribe the village association to remove the speaker, or pay someone to destroy it. My wife is working on subtler "Thai style" measures to eradicate the problem. :) Your drawings are beautiful. Originally I had a similar design, but I opted for something simpler; it's just me sitting in a room, composing, playing or recording music (much of it computer-generated), and I hate to lose the space. I'm not planning to rent it out, so there is no direct return on investment, and I'd rather drop 86,000 baht ($2,700) on musical instruments. Is that estimate for wood studs, or steel? Wood is the more expensive option, and it has to be treated for termites. A design like yours requires specialist builders, especially for the speaker soffit design (including cooling and electrical work), and they will be more expensive. I've asked my consultant (you may know him) to give me his price. The diffusor information is interesting. The distance from the front edge of a back wall diffusor to the ideal listening position is about 310 cm, 3 wavelengths at about 420 Hz. But if there is still signicant comb filtering out to 7 wavelengths, I could only diffuse above 1000 Hz. There is also the issue that, for a control room, I might not want any diffusion, only absorbsion.