Asymmetrical Control Room Space

Hello All. This is my first time posting a question so I hope I do this right. If not please bear with me… I’m in the process of building a control room in Portland, OR and I need some help with how to orient things and acoustic treatments. The space that I’m using for the control room is a former kitchen/bathroom that is in one corner of a large rectangular space. I’m not going to worry about what to do with the tracking room just yet as we are on a tight budget and are kinda putting this together as we can afford it. I imagine we can muster about $1000.00 dollars to do the remaining work on the control room. My issues are these: 1. The control room walls have already been built and the room dimensions are a bit close to a square which I know is not good but various factors necessitated this shape and size. I would like to make this space work as well as possible. 2. There is on wall which has an electrical breaker box attached to it which we simply cannot afford to move right now. This creates a space which is asymmetrical which I realize is also not good… I’m planning on using a space that is currently a shower to put tape machines and power supplies in to isolate their sound. There are two blacked-out walls in my sketchup that I can’t move/tear down. This doesn’t have to be a world class control room (I’ve been working in acoustically imperfect spaces for many years) I just want as good of a layout as I can get under the circumstances. Noise is not an issue. So… My questions are these: 1. Which way should I orient my monitors? And where should the listening position be? 2. What sort of acoustic treatments/splayed walls would be beneficial? 3. The ceiling is currently 11’ 9” high. Should I hang another ceiling below that in order to better control the acoustics or should I just attach acoustic treatments to the ceiling that already exists? 4. What about hanging an angled ceiling?!? Thanks in advance for any and all help!!! -Collin

you could do something like this - and add a cloud ceiling. cheers john

Thanks a bunch John. I had toyed with doing something like that myself. My only question is this: On Ethan Winer's Acoustics FAQ page he states that larger acoustic spaces are better acoustically and he suggests a minimum 2500 cu/ft. for listening/control rooms. Do you think the gains made by your design would outweigh the loss of space? Thanks a bunch. -Collin

Also... I'm having difficulty finding info on what exactly a cloud ceiling is. Is it just hanging panels of rigid 703 fiberglass? Also are there guidelines as to amount and placement of such clouds. I've been looking through the forum but haven't really found this info. (sorry if i missed it). Thanks again in advance! -collin

The angled walls eliminate flutter echo, so let you only use as much absorption as is necessary for first reflection points (including ceiling, which is the purpose of the "cloud" - while Ethan is right about cubic volume, a CR is better with a bit dryer sound so you don't assume that the reverb you're hearing is "in the mix" - so a smaller, more absorbed room can work OK for a CR. If you're in doubt, get a few rolls of masking tape and tape the floorplan out on your floor; it doesn't hurt to even move things into place and do a "walk-thru", so you can see if it'll work for you or if it's too cramped (ergonomics and acoustics don't often go together peacefully, so this is good to know ahead of time) That excercise will help you decide what'll work for you... http://www.recording.org/ftopict-26889.html http://www.johnlsayers.com/phpBB2/viewt ... 1&start=90 Couple of cloud ideas... Steve

I made a rough 3D version of John's suggestion for a design. It looks pretty good. I think I will do the taping off of the room and see how it feels for real but i intend to procede with this design and I'll post pictures when i can. Thanks for all the help!!! -Collin

Hello. I'm getting ready to build this beast and I just had a few questions that could use clarification. I'll be refering to the picture attached to this post which is based on John's suggested design. #1. I'm assuming that the brown corner walls are to be similar to the design described as corner asborbers in the link: http://www.johnlsayers.com/HR/index1.htm Is this correct? Is it ok if they're a bit free standing like this? #2. I'm also assuming that the middle pink wall is just really a frame which is covered with cloth and that has OC 703 behind it. Is this what John was suggesting? #3. And I hate to even ask this question.... but.... We're considering soffiting speakers within the brown wall. Do you think its worth the trouble or should we just stick with the free standing near fields that we already have? Would it be a good idea to have both? Obviously all that we really need is ONE acurate monitoring system. Thoughts... Thanks Again. -Collin

Aloha Collin, Looking good. :D

#1. I'm assuming that the brown corner walls are to be similar to the design described as corner asborbers in the link: http://www.johnlsayers.com/HR/index1.htm Is this correct?

Somewhat, yes. However, if you decide to soffit mount your speakers, you want to have the area around the speaker face (bezel) a solid surface rather than slats.

Is it ok if they're a bit free standing like this?

They will still work if they're free standing, but if you're in a more permanent situation (unlike myself), and since you'll have to frame the front and side walls anyway, why not just frame the corners as well and build it into the room? You'll have a lot stronger unit overall, and a cleaner looking result.

#2. I'm also assuming that the middle pink wall is just really a frame which is covered with cloth and that has OC 703 behind it. Is this what John was suggesting?

Basically speaking, yes. Small rooms tend to need a lot more absorption. As such, the front wall/ front corners are among the key locations to incorporate as much absorption as possible. The rear wall, rear corners, ceiling and side walls also need to be treated. See attached pics for some examples.

#3. And I hate to even ask this question.... but.... We're considering soffiting speakers within the brown wall. Do you think its worth the trouble or should we just stick with the free standing near fields that we already have? Would it be a good idea to have both? Obviously all that we really need is ONE acurate monitoring system.

There seems to be two schools of thought here. Bryan Giles, Aaronw, Andy Wheeler, and many others have all soffit mounted their monitors. I've chosen to soffit my Mackies HR824's and they sound great. Some of my impressions after soffiting: - bottom end is tighter - imaging is clearer - drums sound clearer, more defined in mixes - able to hear clearer at lower volumes than before - room sounds quieter without music playing, louder & tighter with less effort when music played - less fatigue/more enjoyment in listening to mixes! Another benefit (among the several benefits) to soffit is that it saves precious floorspace. Be sure to allow adequate cooling if you are using a powered speaker. Soffit threads that come to mind: http://johnlsayers.com/phpBB2/viewtopic ... highlight= http://johnlsayers.com/phpBB2/viewtopic ... ight=#2596 http://johnlsayers.com/phpBB2/viewtopic.php?t=4773 http://johnlsayers.com/phpBB2/viewtopic.php?t=4091 Hope these help, Aloha 8)

Aloha Collin, A couple of more (hopefully) useful drawings :D Aoha 8)

Wow! Thanks for the data/diagrams/pictures. That clears quite a bit up for me. Two immediate questions come to mind in looking at these: What are those "Acoustic Hangers" exactly? Just hanging foam or a tube bass trap? Also, those air holes that provide circulation only needed for self powered speakers to release heat or is there an acoustic purpose? Cheers, Collin

Aloha Collin, Glad they were helpful. :D Here's a few pics on acoustic hangers. I've read posts where any of the following materials were used: pink fluffy insulation, rockwool, OC703, or polyester batting over a 1/4" sheet of masonite, fiberboard, particle board, hardiboard, or plywood. Here's an explanation by Steve on how they function:

The actual HANGING part of a trap such as this uses a different principle for absorption - it actually relies on the hanging mass to move a little bit, somewhat similar to the "soft" styles of martial arts - in order for the bass sound waves to MOVE the hanging mass, they have to release energy - then that energy is no longer sound, but (slow) movement. Also, some of the energy is converted to HEAT, same as normal absorbent types of traps. The "normal" way of building such a trap is to line it with the denser rockwool type materials, then wrap the actual hanging parts with lighter, fluffier insulation - part of the purpose of the lighter insulation is to keep the individual boards from banging against each other or vibrating; part is to absorb any higher frequencies as well. As far as I know, there is no good reason to use one type of insulation over another, as long as you do NOT use any of the foam type insulations; but any fiberglass or mineral wool insulation should work. The boards themselves can be hung as close to each other as you can get them and still have them hang freely; the more of them in a space (still free) the better the absorption. It's more efficient if the boards are neither parallel or perpendicular to the entering sound waves, but instead hung at an angle.

The "holes" behind and above the speaker area are for ventilation/cooling for powered speakers. The hole below the 5/8" plywood/insulation/cloth area is to allow the bass frequencies to enter the trap. Aloha 8)

Hi All. I'm now finally getting ready to start construction on this front control room wall. I recently posted some questions in the "Speaking of Speakers" section regarding specific soffiting questions, but I guess this is more of a design/construction issue. (although they all seem to run together...) At any rate, I'm working off of the general layout that John suggested to me previously. I'm gonna start with some basic questions to make sure I'm headed down a sane and solid path... I've attached a jpeg featuring more exact proportions and angles. 1. Does the general geometry of this layout make sense? Will the speakers be too close to the side walls? Is the listening position too far back? 2. Should the Slot Resonator between the two Soffit Walls be effectively sealed from the space created behind the Soffit Walls? Or should air be able to move freely behind that entire area? Thanks so much for eveybody's help! Collin

Aloha Collin, Congrats on starting your build phase. :D Any chance you could post your skp file, as appears to be a bit different from John's design? It's important that the side wall angles, soffit angles and depth of the front wall/soffits are as close to John's plan as possible, as there are certain principles involved that the design is based upon. Any changes/compromises from those design principles will also change/compromise the outcome of how your room will sound in regard to the designs intent. :shock: Aloha 8)

Aloha, Perhaps something more like this? Aloha 8)

Kendale, I can't thank you enough. Here's the .skp of the control room as it is now. Dimensions and lengths are acurate to real life from a birds eye view. I haven't started the front/soffit walls yet as I want to get my design right. As you see I've tried to make the room mostly symmetrical and have the 60 degree speaker angle from the soffit faces to the listening position. I see you think i should move all those front walls a bit further out (like John's design). What are the specific design issues I'm missing? Thanks so much again.

Oh yeah... Here's the jpeg that corresponds to that skp file.

Aloha Collin,

(from skp file) I wanted to make this wall at a greater splayed angle but was unable to. This was the best I could do.

Yeah, I'm with you there. There are so many things I wanted to do in my build, but wasn't able to - like having a separate building for starters, but we do what we can, eh?. :wink:

As you see I've tried to make the room mostly symmetrical and have the 60 degree speaker angle from the soffit faces to the listening position. I see you think i should move all those front walls a bit further out (like John's design). What are the specific design issues I'm missing? Thanks so much again.

Hey, no worries! :D Okay, according to your skp file, the right hand wall is angled @ 6.5 degrees, but the left hand wall is square @ 90 degree. (This gives you only a 3.25 degree angle for both walls, provided you angle the rest of the layout.) John writes in the SAE (http://www.saecollege.de/reference_material/index.html) section on room shape & size -

I believe that a wall must be at least 12 degrees off parallel to stop parallel wall standing wave interference. That's either one wall at 12 degrees or two walls at 6 degrees each. If you can afford to make the angle bigger, do so. Also you can create angled walls within a rectangular room by adding acoustic treatment. (I'll demonstrate that in the pages on wall treatment). (Note: having non parallel walls doesn't entirely stop standing waves - they still form within a room but along different lines of repetition). The main reason for having angled walls in a control room is because of reflection control of the high frequencies for true imaging from your speakers. John Sayers

So one of the principles I was referring to was having both walls angled (at least 6 degrees each) in order to acheive symmetry left/right of the mix position. The few inches lost are more than compensated by the benefits of having a clearer image at your mix position. There are several ways to approach this: - If the left hand wall is already built; start by considering it "already angled @ 6.5 degrees" and layout the rest of the room from there. - If it's not already built, could you angle it 6.5 degrees out into the live room area? - "create" an angled wall using acoustic treatments (this will force you to reconfigure the rest of the room accordingly) If this angle is really all you have, then work with that. Be sure to angle the rest of the room accordingly and use as much acoustic treatments as you need/can/are able to in order to control reflections, especially at the mix position. The second thing would be to center your monitors (horizontally) on the 3'7" soffit face between the side walls and the front/center wall section. This should put the center of the monitor (LF/HF) @ about 1'9" horizontally. Your monitor height – woofer (some say HF) at ear level (avoid mid point of floor to ceiling measurement – either sit higher or lower if necessary) If you want to mount them high you must angle them down so that they point at the engineer. (FWIW, my console stands 37" tall, so I ended up using the "woofer @ ear level" approach.) Finally, regarding the front wall; while there may be several other reasons why John chose to draw it the way he did, one thought that comes to mind is by having it out from the wall a bit further it allows you to have more trapping and treatment, which also improves your isolation. The 6" difference in room length will for the most part be mostly unnoticable. Hope this helps, Aloha 8)

Well, I've decided to go with a slightly angled soffit wall to get the speakers a bit higher as my ceilings are high and, well, i can... (see attached jpeg) I've also decided to put my speakers on free standing wooden "stools" inside the soffit structure to isolate them from both the soffit wall and the main wall. Thus far I've built the frame and the "stools" and i'll be posting some pics later today as soon as i can. Three questions: 1. Am I correct in assuming that all the walls and ceilings behind the soffit should be covered in isulation? Can it be the fluffy pink stuff? 2. Does the airspace behind the slat resonator (in between the angled soffit walls) need to be isolated air-wise from the space behind the soffit walls? Or should air flow freely behind the entire structure? 3. Any thing i should watch out for when putting these speakers on freestanding "stools"? Does it need to be a very rigid stool for example? Thanks and I'll be back with exciting pictures later today!

Still wondering if i need to sperate the airspace between the soffit area and the slot resonator area? If i do, do i need a "dividing plate" to seperate above and below the speaker box to force air to go through the holes in the speaker box? Is this speaker stand idea any good? Cheers!

I guess this is what I'm asking about....

its a good idea to split the sections like you've drawn it. this way your trap spaces can each be their own "spring" space. you can tune them each independently. you should probably go with the heavier insulation rather than the pink stuff in this small space as it will be more effective. if you had a lot of air space you could go with the lighter stuff.