Acoustic treatment advice please

I have a detailed post on the studio construction page under Building a Quiet Space in Walkout Basement http://www.johnlsayers.com/phpBB2/viewtopic.php?t=7960 I'm at the point where I could really use some input before I take a stab at room treatments. Bought 36 pieces of 2" x 2' x 4' 703 equivalent (Mansville Spinglass 3lb/sq. ft. density) to work with. Would like to use studio for multi-purpose recording.. everything from drums to vocals and acoustic to rock. Using Mackie HR824's in a stereo monitor system. Have looked around this site and others and would be up for building anything from a rear CR diffuser to slat resonators or clouds so with that in mind look at the attached layout in MS Word and please chime in. Ran RT60 and Room Mode cals and came up with a few ideas for comment. Tracking Room Data Modes 50/68/76/100/136/150/152/200/204/229/272/305. Q - With the RT60 calc I completely treated the ceiling and the two windowless walls with OC703-4". The resutant RT60 values were between .17 and .12 with hardwood floor. Do these RT values seem appropriate for my desired applications? Q - If instead I install a full length slat resonator on these walls with OC-703-2" placed 2" out from the wall will I achieve similar LF absorption? Q - Also considered putting short slat reso on 12 degree angle to offset opposing wall. OK? Q - Would this approach make the the room too bright. Two walls would be all glass and door, the other walls would be slats and the ceiling would be all HF and Mid Absorber. Q - The ceiling would be OC703-2" installed 2" out simply covered in burlap. Is this a good idea? Control Room Data Modes 34/37/68/75/77/102/113//136/150/154/232/309 Not so good, huh? In the CR I thought I'd follow Johns Wall Units plan except I have a drawing of a modified back wall array to share for comment. See attached CR Wall Unit .doc. Will it compromise effectiveness if instead of building/joining 2 LF corner slat absorbers and 2 rear absorbers as per the John Sayers Wall Units plans I: Q - Seal the existing walls at the back of the CR and make one continuous large cavity? Q - Cover the corners with slats and bass trap guts? Q - And then front mount fabric covered OC703-4" along the middle of the array (without slats) for the Rear Wall Absorber? Thanks, Charlie

how is your isolation at this point? is the room actually as quiet as you wanted it to be? assuming it is, you now want to treat the space. I recommend measuring the actual room rather than calculate it. if you don't measure, then the basic advice would be to use broadband treatments. since your "control room" is an open space, you may find adding free standing slat resonators to even the symmetry around the desk will help. I'd keep the space as live as possible and use drapes or reverible absorber/reflectors on the walls to alter the space as needed - live to dead. for the back wall, you could build slat resonators and absorbers to control the reflections back to the desk. see image. you'll want to segragate the sections to improve the efficiency of the slats. you can build a couch riser to get the folks seated there better aligned as well.

Wow Glenn, thanks for the help, the sketch is great. The isolation room seems really quiet when I'm working in there.. no airplanes, cars or dogs like before. We'll see how the testing goes. Thanks, Charlie

John, I'm ready to add slats to CR broadband side resonators. Attached are the results of the R Plus D Freq Response Tests taken at the mix position and a floor plan in MS Word. I'm not sure how to interpret the test data when it comes to tuning the resonators. Would you please assist? Sorry about the jpeg size but I had no luck trying to shrink... iphoto kept locking up. Thanks, Charlie PS, one more question concerning the LF absorber in the rear left corner of the CR. Its 4" of rockwool in front of a sealed cavity. I installed assorted hangers inside and I wonder if the cavity should be vented to make the hangers more effective. Could vent out the front or rear if needed.

Charlie - first I'd use the full space behind the left slot resonator. make the resonators broadband, I'd divide the left side resonator into two ot make it even more broadband. The opening to the hangers is fine - leave it open. cheers john

John, There is currently no direct opening to the back corner cavity/hangers just what passes through the front panel rockwool. Do I understand you to say leave it this way or make a vent in the back? The wall resonator units are already finished and fabric'd and each side is actually three sealed cavities, see photos. Can I just use 1" x 6" planks 1/2" apart horizontally all the way down the length of the entire unit? Finally the space on the left wall behind the slats.. are you suggesting more slat resonator area or a 2" 703 absorber panel? Thanks, Charlie