cement wall, symmetry + ratios for studio design

Posted: Thu Jun 21, 2007 8:39 pm

Coming off of 2 reads 'Acoustic Design for the Home Studio' and 'Build it like the pros'(where I found this website), I'm now WAY motivated to get out of my 9' cube and move to the basement. Have learned alot from both, but as with most people, my options and needs are a bit unique - and my research has come up a bit short on a few issues. I think I have a decent idea of what to do, but appreciate any feedback.

Fortunately, isolation is not a concern - my 9'cube room is quiet enough at the times I record, and the basement is even more so. I'm hoping to build (as affordably as possible), the best room I can for monitoring mixes and tracking vocals - all other tracking is direct.

2 room build options (3 walls already in place on either):
A: 13'8"x11'5"x8'10" (#2 Sepmeyer ratio), near perfect symmetry with virtually no obstacles.
B: 21'3"x14'x9'10"h (with I-Joists (see below)- option to make the ceiling lower) - follows the .618 rule loosely, but also has a 3"x14" support joist the runs the width of the room 4' from what would be the front, and a 12"x30" vent spanning 3/4's the way across the back width.
My assumption here is that size(along with proper treatment) trumps perfect ratio/symmetry, but if not - smaller would be a bit cheaper.

My basement is poured with a brick mold, and either room would have a cement front and side wall (the larger room would have an add'l 4' cement section along one side(front)) with the back wall (on either room) being a 2"x6" wood framed wall. My plan is to build a standard 2"x4" wood stud side wall with the inside consisting of drywall under a raised-brick panelling. I would leave the outside of this and the rear wall exposed - the rest of my basement is failry large. I'm hoping the panelling will acheive as close to any symmetry I could acheive(mids/highs) with the molded cement wall just short of building a brick wall. Also, don't think there would be any advantage to insulating/drywalling the exposed walls - couldn't really find any info on these issues, so any suggestions welcomed. Again, with proper treatment, I really want great stereo imaging for monitoring.

The ceiling(upstairs floor), is exposed with I-Joists 16" on center running the length of either room. My assuption would be to drywall the smaller room (with proper treatment) for a perfect ratio - but in the larger room - leave it exposed, treating the front area fairly heavily, and experiment with the back part of the room for a live feel ?

I've read several articles on vocal booths, but haven't found any on recording vocals in a large room. As most of you can guess, even with significant treatment and an SE reflexion filter, vocals still come off fairly 'boxy' in a 9' cube. I'm looking forward to experimenting once built, but any suggestions regarding the build that would help - or any articles... again are appreciated.

Dean

Posted: Wed Jun 27, 2007 12:17 pm

Anyone ? Not enough info or am I just too far off base ? Any short opinion welcomed on any of my questions.
Quick summary (details above) Goal - Best room for monitoring mixes and tracking vocals (isolation not an issue) - upgrading from a 9' cube.

2 room choices in basement:
A: approx 1400 cf room - near perfect symmetry and ratio - no obstructions or...
B: approx 2700 cf room - decent ratio with some obstructions - assumming proper treatment for both, do I stand to gain alot with a larger room ?

Wall construction:
A front and side wall in place are cement with a layered brick pattern mold, the back wall is a 2"x6" frame awaiting drywall. My plan for the 4th wall is to build a std 2"x4" studed wall - layer the inside with drywall followed by panelling with a brick pattern (for both looks and some symmetry?) leaving the outside frame exposed.
My thinking here is bass escaping the back/side/ceiling(into a much larger space) would be a good thing requiring less treatment inside, and any deviation in symmetry with the side walls (cement vs panel/dw) regarding mid/highs would be controlled via proper treatment. Are these bad assumptions ? An alternate would be to drywall (or wall) the cement sidewall - in addition to more work and money, I fear issues arrising similar to floating a floor ??? - I would do though if I stood to gain alot.

These are my key and most pressing issues - any comment on others requested above also appreciated.

Posted: Wed Jun 27, 2007 5:41 pm

I would use the larger room. Your dimensions are similar to mine.
(http://www.recording.org/ftopict-31197.html)

The bass trap-loose coupling of the back wall would help as will the exposed rafters. Consider setting up along one of the long walls to get less early reflections from the side walls. My room is roughly this size.

Consider building bass traps into the corners if possible.
Consider a panel bass absorber above the half brick wall
Put lots of broadband absorption on those full brick walls.
Put diffusers in the rafters.

peace
Phil

Posted: Wed Jun 27, 2007 7:03 pm

Thanks for the response and the trap suggestions. I plan on putting bass traps in all corners, as well as experiment with additional ones in the ceiling/wall corners and or near the obstructions.

I am leaning towards the larger room although I haven't really considered setting up along the long wall - what I've read suggest running the length of the room... maybe more of an issue when isolation is more heavily implemented ?
I like the idea of having a 'live' end, and am not sure I want to run against the rafters, (even with alot of absorption), but the option of running that way does open a 3rd possibility of making option A a little bigger plus an open ceiling(throwing off the ratio a bit). More things to consider... I like ruling out all options though.
Thanks again for your response.

Posted: Sun Jul 01, 2007 10:50 pm

i would split the large room into 2 space - run the CR along the 14' length, and have the other section be your vox/live room. assuming you're going to put something on the ceiling and want to treat the block walls somewhat. put the dividing wall out starting at 15 degrees 11' (narrow end of the room) from the corner where the outside frame wall and block wall meet. this puts the live/vox room on the side with the most block walls where (someday?) you may have the most volume. put in a glass door beween the CR and live room. put the main entry in the live room so you can put a couch in the back of the CR...

unfortunately i cannot post the drawing i made here...

Posted: Mon Jul 02, 2007 9:18 am

Sounds like a good set-up and I appreciate the suggestion, but I'm pretty sold on the 1-room concept - for monitoring, everything I read keeps suggesting going large and to conform to certain ratio rules(or staying away from 1x, 2x, .5x multiples), and maintaining symmetry.

I'm going with the large room (did some detailed measuring last night). Its situated in such a way, that if I decided on a dedicated vocal booth/area I could configure one of the adjoining rooms at a later date - for now, I'm planning on heavily treating the front, and leaving the back-end open. My biggest issue (I think) given the walls and obstacles is in trying to maintain symmetry - I'm guessing a big investment in treatment once built, but I'll take it one step at a time.

Thanks again.

Posted: Mon Jul 02, 2007 8:57 pm

the challenge will be that such a large room will likely need to be pared down because of the ceiling height even though you want to retain the volume, the symmetry and ratios will be tricky. here's what i was thinking might work.

Posted: Wed Jul 04, 2007 7:37 am

Thanks for the drawing - I like the way you maintained symmetry in the control room, and offset the vocal room. Given the obstructions I have on both sides of the larger room, I'd have to take the ceiling far lower than I'd like (I want to keep it as open as possible) and work around a couple of windows that don't really interfere leaving it as 1 room.
If the 1 room concept doesn't work as I hope, doing something like this after the fact wouldn't be a stretch, especially if isolation became a concern - food for thought going forward.
Thanks.

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