Control Room Design Help Needed - Trap Placement

Hello forum members, i ran a post a few months ago that detailed plans for my new control room. It can be found here: http://www.johnlsayers.com/phpBB2/viewt ... 5906#55906 After hours of reading through this great site and also Ethan's forum and acoustics articles i think i have my acoustics in order. Apart from thanking everyone involved in this site for their benevolence i must also thank my buddy "Joel" for spending hours on this 3d model. BASIC ROOM INFO: The room will be used purely for mixing and sequencing - i will record in adjoining rooms. Dimensions: Length 4100mm (west and east walls) Width 3640mm (north south walls) height 2500mm Construction: Walls - Solid Brick Floor - Oak Hardwood on joists and bearers. 1 ft airgap to dirt - have put sound absorbing material (residential stuff) in between the joists. Ceiling - Plasterboard 10mm suspended on faring channels - will add insulation at a later date. Window - 9' x 4 1/2' Crappy aluminium window - 4mm standard glass Doors - cavity slider (near dj decks) 720mm wide x 2040mm. - entrance south east corner - 820 x 2040 - acoustic seals solid mdf. I was hoping to gain some constructive criticism regarding the placement and construction of my traps and monitor placement: 1. The front corner traps (north wall / window) are 'superchunks' they will be made from 705 equivalent material. The left one is 500mm x 500mm or 1'8" x 1"8 and it is in two sections (one under the desk and one above) they have a total height of 6 feet. The one on the right is smaller 250mm x 500mm or 10" x 1'8" as the window gets in the way. I can make it move out an extra 70mm if i cover the window frame. It has a height of 4 feet. 2. The first reflection side panels west and east walls are three 600mm x 1200mm or 2'x4' 50mm or 2" thick 703 sheets with 2" airgap to walls. the frames holding them are 100mm or 4". 3. The back wall (South wall / DJ setup) is almost entirely covered by 2" 705 or 703 ? with 2" airgap. total surface area is roughly 9' x 7'. 4. Above the djsetup is a "superchunk" joining the rear wall / ceiling axis. it is 2' x 1' and 9' long. 5. The ceiling hangers are 15 sheets if 703 2" that are 2' x 3 1/2'. They are angled at 4" from the ceiling to 8" from ceiling. 6. The main desk will be fixed to the north and west walls. My monitors will sit on this desk maybe on auratones or audiophile spike kits. QUESTIONS: Do i need all of these treatments and should i modify them in any way? eg: i could make the side traps in a 8" frame and add 4" or even 6" of 703 or 705. I could also make the rear trap 6" but this would be really hard - prefer not to. What types of material should go where? I was thinking 705 for bass traps (superchunks) and 703 everywhere else) Are there too many traps - i followed Ethans mantra - " you can never have too much bass trapping" - Finally are my monitors going to be accurate sitting on the desk or should they really be on sturdy (sand filled) speaker stands? Looking forward to your responses. Thanks in advance!

bump... :oops: I hope i have followed the rules properly??? i am desperate for any feedback as this has been doing my head in and i was hoping to finalize the design and build the furniture etc in a week's time (work holidays). Want to get it as right as can be before i sink 2 gorrilas into buildng this stuff! Here's hoping! thanks 8)

Aloha, One of the things you might want to consider is the importance of achieving symmetry in your room design and treatment placing. Any chance you could you post the skp file, please? Thanks! :wink: Aloha 8)

i'm no expert in anything... however, i'm fairly certain it is better acoustically in the control room for your ceiling to be lower at the front (near your monitors) and to gain in height towards the rear of the control... if i interpretted your models correctly, i think your ceiling is "backwards!" (very well done models indeed!) cheers! kevin

kendale wrote:

Aloha, One of the things you might want to consider is the importance of achieving symmetry in your room design and treatment placing. Aloha 8)

Thanks for your reply Kendale. I thought that the room was fairly symetrical as the monitors are almost centered (i can move one of the lcds to put the speakers dead centre) and the side absorbers and celing absorbers are symetrical and identical. Do you mean that the smaller superchunk (right hand side - window) will be an issue? I was hoping that the bed which is also on that side would act as a bass trap to some degree. the rear wall and rear superchunk are almost symetrical - making it smaller would make it symetrical - i thought it would be better to leave it bigger. Would it be wise to run a thread in the "acoustics" forum to discuss the type of traps and thickness etc. or keep it here?

kendale wrote:

Aloha, Any chance you could you post the skp file, please? Thanks! :wink: Aloha 8)

The images were created with Lightwave 3d modeller. I can send you a file in this format if you have it though. Kevin, thanks for your reply also - yes i can hang the celing absorbers in a different way - if i drop em more at the front and place them in a straight diagonal line until they hit the celing where the rear wall superchunks are. Keep the suggestions coming i really appreciate it!

Aloha,

The images were created with Lightwave 3d modeller. I can send you a file in this format if you have it though.

Thank you for offering, but I'm afraid I don't have that program. I wish I did though, as the renderings look great! :wink:

I thought that the room was fairly symetrical as the monitors are almost centered (i can move one of the lcds to put the speakers dead centre) and the side absorbers and celing absorbers are symetrical and identical.

For the most part, the side & ceiling absorbers are fine as far as placement and symmetry goes. You may find that multiple flat ceiling absorbers will work fine and be a lot easier to build & install. Am I correct in my understanding that the layout prescribed by Glenn (bed centered on rear wall/wrap around work station) in your other post will not be used? It was a pretty good suggestion. So, the areas in question are: - what appears to be a desk of some kind on your left, and the bed on the right. While they may have a similarly sized footprint, their reflective/absorptive properties are quite different. • Left/right room symmetry (at least within a foot or two of ear height) is important for good stereo imaging. - the off centered positioning of the rear wall unit. Could the wall unit be centered on the rear wall, and ceiling corner trap run the full length of the wall? This positioning may also allow for corner traps in the rear of the room in addition to the proposed ceiling corner trap. - Perhaps some type of window treatment to stop the reflections off the window into the mix position.

Do you mean that the smaller superchunk (right hand side - window) will be an issue? I was hoping that the bed which is also on that side would act as a bass trap to some degree.

While the bed may have some degree of absorption qualities, it's a bit difficult to predict what kind/how much/to what extent it will have, so I would not count on it as an integral part of your design.

Finally are my monitors going to be accurate sitting on the desk or should they really be on sturdy (sand filled) speaker stands?

• Monitors should NOT sit on the console but behind, placed on heavy decoupled stands - console placement causes early reflection problems in most cases, unless the console is slanted down in front a LOT. They would be better on stands, angled in 30 degrees, and the two legs of equilateral triangle comprised of two speaker centers and a point about 10" behind your head. • Distance to wall behind speakers will change response drastically - there is a wall bounce calculator on the Acoustics forum that's fun to play with (needs Excel) • Moving either speakers or your head by as little as an inch or two can sometimes make drastic changes in response, due to modal peaks and dips.

Would it be wise to run a thread in the "acoustics" forum to discuss the type of traps and thickness etc. or keep it here?

Chances are that it's already been posted; its just a matter of finding it in the wealth of info available. Perhaps a search would prove fruitful. Hope this helps, Aloha 8)

i think the biggest challenge for you will be the symmetry of the space. the difference between the two side wall treatments will very likely cause you to feel a bit off balance until you "learn the room" and compensate for it. you might be better off turning things sideways and putting some more absorption over the bed.

Hi Kendale, Thanks for your detailed post! You are right in suggesting that Glenn's (old post) suggestion is a good one. I had considered it but the problem is that there is two doors there (hard to see in some drawings). The gap in the rear wall absorber and superchunk is to accomodate the door that swings out from the east south wall junction. The only way for it to be possible is that i would have to get a fold out sofa bed and live with a dodgy back (i tried out a heap of sofa bed's and i couldn't find one i thought would be suitable for daily use) ..... (this would have been ideal acoustically as the back wall would have been a soft sofa bed and huge rear wall absorber. The second problem with this is that i would have lost all the usuable shelving space above the sofa bed unless i made shelves above the sofa - in any case hard to lean over a sofa. Its important to me as i have thousands of vinyls (DJ) and i neen them to be close to my decks. As for my monitors - can they be placed / raised on stands placed on the desk or mst the stands be coupled to the floor. it would be hard to bring the desk out as it would block the first of the three 19" rack cabinets under the west wall desk. I was thinking of isolating them and raising them from the desk using auralex pads or stands and spikes.... What do you think? [/b]

Thanks for your reply and drawing Glenn, Your ideas are always good. I had thought about this option and luckily for me i can implement it using the current furniture design - giving me the option of both setups. What is preferable in terms of design? Option A: (My design) PROS: +Speakers centred +firing down long room axis +equal side traps +equal celing traps +almost equal rear wall and bass trap +almost equal front corner traps +all my equipment fits in the room as i have used every amount of available floor and wall space well. CONS: +Difference in surfaces of left and right sides of room - Left side desk = hard surface - Right hand side Bed = soft surface +Mounting speakers desk in front of glass window? Option B: (Glenn's suggestion) PROS: +monitors centred +can mount speakers on stands coupled to floor and bring desk out (room alows for this) or bolt stands to the wall +similar surfaces on both sides desks (hard surfaces on both sides) +similar surface on rear wall (all soft) +equal ceiling trapping +almost equal rear wall trapping +similar distance between objects on left and right sides CONS: +front bass trap in only one side (but might be able to add one to other side) +window on right side of speakers and absorbers on left side +lose a bit of uable space in this config. So i guess ultimately it's a toss up between having an uneven freq response caused by a bed one one side and desk on the other - or by having a window on one side and desk / dj stuff / absorbers on the other... Not sure what would be worse - in both cases it's kinda not perfect but at least i shouldn't have bass buildup and reflection issues, just a slight imbalance between stereo imaging in left and right sides... thanks for all the suggestions up to this point! Keep em coming..

if you build your treatments to be moveable you can try both...

i think the biggest challenge for you will be the symmetry of the space.

I completely agree with this ! Try to make the room or if it's not possible yourself and the speakers symmetrically placed in the room, Can't you just reverse everything and place the bed near the wall and yourself and the speakers on the opposite side of the room but everything symmetrically placed ?