Rick, thanks for the helpful insight. I'd love to be able to do wood floors too. Maybe if I can find an inexpensive flooring to use I'll do it, but
Bruce Hardwoods run around $7/sq.ft.
The tracking room alone is over 600sq.ft. so thats $4200!
There goes my 6 pack of Brent Averill API mic pres for the drum kit
Now for your questions:
I see you had diffusers along the tracking room perimeter. What type are these going to be?
I plan on using a combination of the varible bass absorber/diffusor that John has detailed here:
http://www.locall.aunz.com/~johnsay/Studio/PDF Files/Variable_Bass_Absorbers-diffusors.pdf
and a series of RPG diffusers on the columns in the tracking room.
And BTW, did you ever work out your well width/depth issue on your control room RPG? I would be very interested in seeing those. I have always wondered what the parameters are for designing a RPG in relationship to room size. I mean, what do you use to determine the starting point of the design. I understand the frequency relationship to the wells themself and the quadratic/primitive root type sequence thing, but not relitive to the room. Are there some kind of room dimensions that determine anything in the RPG parameters?
From what I understand, RPG is just another type of diffusion. So, given that, you would begin by calculating your room modes.
Determine the problem frequencies.
And tune the RPG to eliminate or attenuate those problem frequencies.
Some one here on this board, I forget who it was, made this available:
http://studiotips.com/tools/
It is a series of spreadsheets that are helpful for this type of calculation.
The "Diffuser" spreadsheet has a calulator for the RPG duffusers.
And of course, there's a multitude of
Helmholtz calculators floating around too.
In fact, I still don't understand the underlying design decision hiarchy for absorbsion either. I mean, what determines the what and how of absorbsion use, and type, as I am sure it is not a matter of arbitrary quantity and placement.
Remember, Absorbtion is only one method of room treatment. Diffusion is another. The two are not the same.
Absorbtion techniques are employed to attenuate high frequency problems, and diffusion is used to attenuate low frequency problems. (someone flame me if I got that backwards!) It is my understanding that the best sounding rooms use a combination of both.
Again, running your room modes will determine your problem frequencies, then you have to decide, based on those modes which ones to use. As far as how much to use; well, I'm sure there's expensive acoustic design software that could tell you that answer. I'm going to utilize those techniques I've seen others use here with great degrees of success.
I believe once construction is complete, most of the room tuning is an emperical process. Thanks to this community, we have been given construction details for treatment, calculators to determine modes, and spreadsheets coupled with standard construction techniques to get our designs very close.
The rest is really up to your ears.
As far as construction
I plan on using a scissor truss for the roof and ceiling:
Sjoko, had me convinced on using a cathedral truss because of it's asymetery:
But, well, economics dictate otherwise.
The room walls are 10' high, and the scissor truss provides another 4'-6" of height at the center. (based on my roof pitch and the coresponding internal ceiling pitch.).
I do have a reflected ceiling plan, and I'll try to post it soon.