acoustic treatment ideas

[edit - I changed the Subject and deleted some rambling] Below is my diagram of my new control room, which is 97" * 135" *217" (2.45M * 3.43M * 5.51M). I built the diagram below to start playing with positioning speakers, the work surface, and the couch and came up with 2 optimal positions for the speakers and I hope pretty good positions for me (brown circle) and the couch (at the back of the room). Anyone have any comments about my diagram, did I mess anything up?

The first picture is the control room's back wall. The back wall has a door in the corner. The second picture shows the mixing location. The 2 speakers are in my 2 'favorite' positions. The left one against the corner gives good bass output. The right speaker is in 'nearfield' position but the bass is anemic. I had some spare Auralex Lenrd traps so those are currently standing freely in the front corners behind the speakers. The current console desk, speaker stands, and floor coverings are temporary just to try out the room. My hope is to get the acoustics good first, then work out my workflow before I design the desk.

Here's an image of the control room and surrounding rooms. Also attached is a sketchup file of the control room only.

[Edit: I deleted some of the questions that are no longer pertinent and shortened some other sections] OK, here are the missing details as required: Where I am in the process: The basic room construction is complete. I'd like to keep the room rectangular (this is a temporary space that must be destroyed when I move). How loud am I?: I mix around 85db,it shouldn't be a problem with my neighbours. The long uninterupted wall of the room is shared with my neighbour (think townhouse). However, I built a false wall with 2 skins of drywall - but it touches the existing porch roof structure which bolts into my neighbours house. Existing Construction: This is a patio conversion. Basic room dimensions are listed in the top post of this thread. The slab is concrete, directly on the ground, thinner than most house slabs. The concrete slab is independent of my house and my neighbours (It's an old porch slab separated by some insulation like what is used between slabs of a driveway). The two walls going into my dinning and living room (see picture) look like this: living room, 2 layers of sheetrock, 2*4 with insulation, plywood with embedded gravel (a type of siding), furring strips, another layer of sheetrock, control room. The wall to my neighbours house is like this: neighbours front room, 2 layers of sheetrock, 2*4 with insulation, plywood with embedded gravel (a type of siding), 2" air gap, 2*4 with insulation, 2 layers of sheetrock, control room. The outside wall is sheetrock, 2*4 with insulation, and plywood as an outer skin. The ceiling is sheetrock, a grid of 4*8s and 2*4's stuffed with fluffy fiberglass insulation, some air space, a plywood roof painted with rubberized roofing paint (hope it doesn't leak too much!) Budget: I'd like to complete the treatment of the room for around $1000. This project is at my house in Saudi Arabia. Construction materials are very expensive and hard to come by. Existing Materials: I currently have - a bunch of spare Aurlaex 2' * 2' * 2" foam 'wedge panels' and - 8 Auralex Leonard bass traps from an old control room available as existing treatment materials - a nice 80-year old tribal rug from Afghanistan - a bit of left over fiberglass insulation (fluffy, foil-backed home wall stuff) -I may have a source for Rockwool, but they haven't answered my calls for overweek. I think my order is too small to be important. Do It Yourself Skills: I have decent woodworking skills and access to an excellent shop full of stationary tools - but wood is outrageously expensive - think like $5-10 for an 8' 2*4! Doing a single slot resonator with pine might cost $500. Goals: I'd like to create a reasonable sounding room that is used for mixing, mastering, and DI-based tracking. Questions: 1) Any suggestions for placement of traps, panels, clouds, new false walls, etc. 2) Any creative ideas for treatments if they are needed in front of the sliding glass doors? 3) Could I make reasonable bass traps in the front of the room by gluing the foam Auralex Lenrds to the wall, put say 8" of fluffy pink insulation in front of them, and then cover with a wood frame covered by flame-resistant fabric? 4) I have some cloth vertical blinds on both sliding glass doors. They aren't in the control room currently, they are in the adjoining rooms. Will it help to move these vertical blinds inside the control room, maybe put one on the sliding glass door to the right of the mix position and put the second one on the opposite wall. The second blind wouldn't be covering anything other than wallboard, but it would retain some symmetry. 5) Any other ideas?

[Edit-updated Rockwool supplier info] Here's my room mode distribution plot. It doesn't look too bad. Today I carpetted the front 3/4 of the room. I know that's not ideal but it was free and I have 3 studio projects backed up. I brought a sub woofer into the room and time-aligned it with the Tannoy Reveal tops. It helped to full out the bottom end but I obviously still have some problems to work on. It may take me a year to tame the room but I'll do it while I'm working in it. I found a semi-local source for rigid Rockwool, but the guy on the phone wasn't very helpful. He said - 'we can make you anything you want, any thinckness, any density' - I thought - ohhh, this sounds expensive. I've requested a quote for 23 sheets of 4 pcf rockwool. I plan to use this same material for bass traps, side wall absorption, and a cloud. Question: Has anyone tried using metal frames for a cloud? The thin stuff (like commercial 2*4 replacements) are very light weight and might make for a super light-weight cloud. I'm also thinking about building a front-of-room bass trap up both corners and across the wall-ceiling interface, so it's one continuos trap in the shape of an inverted U. What do you think?

Here's a few new pictures showing a new desk I built and the final furniture in the room. I've settled on 2 different speaker positions and 1 location for the current sub woofer. I hate to use a sub but my speakers needed the boost - so I did some careful sub positioning starting with the room mode diagram, then fine tuned with a small time delay on the tops to phase align at the crossover of ~ 50Hz and used a 1/24 octave RTA to find the final sub position in the room. I had some Auralex foam left over from another room so I threw it up to help as best it can. The room actually sounds quite good, but as you'll see in the next post I have a few problems to deal with. My wife (in the corner) and a neighbour volunteered to paint! Also, note the cynder-block speaker stands in the corner. I have it currently set up so I can easily move the speakers from the desk to the corners to improve the listening experience on the couch. There are 2 2'*3' windows at head height along the back wall, that are currently 'plugged' with some foam.

Here's a fun graph. Hopefully it is mostly self explanatory. The 'chair leaning forward' and 'lean back' meaurements were made with the speakers on my desk. The couch measurement was made with the speakers moved to the room corners. The background room measurement was made with the main computer off but my laptop would have contributed some noise. The db scale is not calibrated to SPL. The listening tests were made at ~85 db C weighted. I adjusted the scale for each plot a little bit (except the background noise). Measurements were taken with SmaartLive and an ACM8000 mic, which should be relatively good within a +/- 2db's. I'm kind of worried about how to tame the really low frequencies, I don't have room for 4' deep traps to capture 60 Hz, or worse yet 8' traps for 30 Hz. I wonder if a 4 foot high gobo of 3" or 6" 4 pcf Rockwool behind the couch will help on the really low frequencies. (I've been waiting over a week for the local rockwool distributor to return my call and give me a quote). [Edit] The thicker bars represent the primary modal 'lows' at the chair listening position.

John or knightfly, Could one of you move this thread to the acoustics forum please? Thanks,

Mark - playing around with a few sheets of foam is just touching the edges of your requirements. In fact if you invited 6 people to stand in the room they would have more acoustic effect as the human body is a pretty good absorber. here's a more realistic solution. There's traps in the two front corners, there's a slot resonator to absorb the low mids plus give you a splayed wall effect on the front part of the room where it matters. Other options are treating the rear wall and adding ceiling clouds. cheers john

Thanks John. The foam is temporary, I've had it for about 4 years and didn't know any better when I bought it. 1) For the front-of-room bass traps should I leave the foam Lenrd's behind the rockwool panels? (I guess measurements will tell). Also, would a 4' high gobo of rockwool at the back of the couch have a significant effect on sub-100Hz? This would be about 3' off the back wall. I'm not sure if this type of bass trap needs to be sealed on the sides or if free standing would do the trick.

Mark -I've put the low frequency control in the ceiling units where they can be 'off the wall' yet not affect floor space. cheers john

Here is my idea of this room I whould use mobile absorbers , to hide the glassdoors while mixing. The back wall should be a dead wall. maybee you like this idea :D http://xs107.xs.to/xs107/06403/controlroomvorschlag1.png peace mika

Mark -I've put the low frequency control in the ceiling units where they can be 'off the wall' yet not affect floor space. cheers john

Ceiling bass traps were in my original plan, but I didn't think they would do much below 200Hz or so due to their close proximity (<12") to the corners. I guesstimated decent broadband absorption above 200Hz. I thought a trap needs to be about several feet from the wall (1/4 wavelength) to do much at 60Hz. Mika, I like the mobile plan. I think Ill try that for the front wall.