CJ2's Basement Control/Recording Room

Hello all, I'm excited to post my design. First of all thanks for this forum, wow, what a resource. I've been pretty much living here (my wife will attest to this), and I'm greatful for all of the shared experience. I want to thank you in advance for your feedback. GOALS: A combo room with a RFZ for mixing, as well as a recording room. I want it open, because I also like to use it for a rehearsal space for my band. In my job (Church music director) I do a lot of audio production so my #1 priority is a great room to mix in. #2 is a live feeling room for recording from vocals to guitars to horns to drums. Isolation isn't an issue (no neighbors, a wife that loves it as much as me). As far as volume goes, I'll compose and mix at a lower volume 75db or so, but I'll also do some final listening for the vibe up around 90db. When I built the room, I researched room modes and built it as favorable a ratio as I could. The walls are poured concrete on two and drywall/4"stud filled with r-13 fiberglass/60 mil EPDM/RC channel/2 layers of 5/8 drywall. The ceiling is the same contruction as the walls except there is 12" of medium density spray foam. The only wall penetration is a door that swings into the space which is the entry door of the room. I've priced out the materials to build, and am ready to start construction. I have a few questions on the design and treatments, then I'm ready to pull the trigger. FYI Ceiling height is 103.5" (9'7.5") DESIGN DETAILS: ~Framed Walls 2x4, 24" OC with "noggins" I don't know what we call them here in the states, probably something boring like "bracing" ~Roxul Rockboard 60 at 2" thick in all stud walls ~Remainder of cavities filled with Roxul Safe (if I can find here in Iowa) for maximum low Q absorption ~Speakers JBL LSR4328 active monitors soffit mounted in a ported box that is extra deep to exhaust a little heat. I'm checking with JBL for recommendations. ~Soffit wood is 3/4 MDF with a birch veneer ~Bezel for the monitors will be solid birch. ~Slats will be solid birch or MDF with veneer ~Ceiling will have 4) 4' x 10' clouds with 4" of Rockboard 60, covered with very thin plastic and velour (I like the velvety look) suspended 3" from the ceiling ~Slat absorbers and bass traps will be covered with plastic then velour ~I'll treat the velour with fire resistant spray material ~I'll have a loveseat or some chairs, I'm going to experiment with these based on the room response when construction is completed. ~Flooring is called Kennecto which is a vinyl tounge and groove floor that simulated a wood floor (quite well I might add). I've attached two pictures and the sketchup file to look at. BUDGET: $4000 USD. I'll be doing all the construction and wiring. My preliminary calculations have me just under $4000, but I can go over if I need to. QUESTIONS: 1) Any design red flags? 2) Is filling the side walls with Roxul Safe going to absorb bass as well as lining the wall with more Rockboard 60 (2") with bass hangers? It's less expensive just to fill 'em up 3) With the various wall sizes, will I have enough broadband absorption? 4) Do you think the back angle slat walls will give me too much high Q reflection for the mix position from the back angled walls? I've not found anywhere that can give me any answer. I've just gone by other studios and mix rooms. 5) Will a thin plastic sheet covering the insulation before the fabric goes on give me too much highs? 6) Any thoughts on potential sub-woofer placement? Thanks again, Charlie

Not really an answer to your questions, just a couple of comments on things that I noticed:

"Isolation isn't an issue (no neighbors, a wife that loves it as much as me)"

Are you SURE about that??? Sound goes both ways: are you absolutely certain that there will never, ever be ANY external noises at all, that might wreck your once-in-a-lifetime perfect take of the best performance ever? I mean things like vacuum cleaners, TV's, radios, cars, people walking or talking, dogs, aircraft flying over, truck driving past, wind, rain, thunder, and probably about a million other things. Are you SURE that those things will never bother you, ever, and that it is safe to spend all that money building a studio with zero isolation? Just a thought. Also, if you don't need isolation, then why are you specifying "double 5/8 drywall with sound channel" on your diagram?

I'll compose and mix at a lower volume 75db or so

That's actually a rather low level. Most people listen to music at significantly higher levels, especially if they have their iPod ear buds stuck right up next to their ear drums, as so many do these days. If you mix at a too-low level, you might end up missing stuff that ordinary people will hear clearly. Just saying....

The ceiling is the same contruction as the walls except there is 12" of medium density spray foam.

What do you mean by "spray foam"?

Speakers JBL LSR4328 active monitors soffit mounted in a ported box that is extra deep to exhaust a little heat.

When you say "ported box", what do you mean by that? Are you just talking about a vented box around the speaker cabinet, where the vents are for cooling, or are you talking about an actual ported box, where you plan to extend the bass range of the speaker in some fashion with a tuned port? --- On your plan, you show two structures up the side of the room, measuring 11' 5/16. What are those? Slot walls? Something else?

6) Any thoughts on potential sub-woofer placement?

Personally, I like to have the sub on the floor between my feet, to get it as close as I can get it to the same distance from my head as the mains are, and for other reasons. But that might or might not work for your room. - Stuart -

Stuart, thanks for the feedback, I'll clarify a bit on your comments. About the isolation, the room is already built with the wall and ceiling construction I described in my post. The spray foam is actually an expanding foam called Icynene. It is a great sealant, good with highs and flanking noise, but poor with lows as it has little density. I should have used a layer of the rockboard in there as well. Live and learn. All in all isolation is pretty good. The one weak spot is lows from the floor above. My alternative, would be to frame in a ceiling and pack it with rockboard. Hmmm, now you've got me thinking. The JBL speakers are an actual ported box. I've been looking at other soffit mounted posts with active monitors and they seem to have slots in the boxes for venting. I'm assuming they are for venting the power section and the bass port. I could be wrong. Again I'm checking with JBL to see what their recommendation for soffit mounting the speakers. Any links would be appreciated. The splayed walls on the pic in the control room area are a slot wall with some absorption in the middle area. The design at this point was Roxul Rockboard 60 at 2" in the stud cavities covered in thin plastic and velour. Then the angled area behind the wall would be filled with Roxul Safe. The slots are there to reflect some of the highs so the room is not too dead. I thought I'd experiment a bit with the slots to get the best room response I could. All of the slot walls are designed this way. I'd love to hear some thoughts on this method. Subwoofer placement makes a lot of sense. Thanks for your feedback. Charlie