Hi MusicLab. Please read the
forum rules for posting (click here). You seem to be missing a couple of things!
That said, neither of your designs is workable as a control room. The first one is completely "backwards", in that it starts out wide at the front and narrows down towards the rear, whereas real-world control rooms do the opposite: they widen out towards the rear, or stay the same width towards the rear. But they never get narrower, since that focuses and compresses bass towards the rear wall: that's a really bad idea, acoustically. You won't find any succesful high-end control rooms shaped like that.
The second design is only slightly better in that sense, but still unworkable: To start with, you are cutting off all the corners! That's where you need massive bass trapping in such a small room. Cutting off the only place where you can have the treatment that you need most, is not a good idea. There are many other things that make that design unusable as a control room, but just from that point of view alone, it should be discarded.
I would suggest that you should do some research, right here on the forum, on current modern control room design concepts and philosophies, and use one of those for your control room. Personally, I really like the RFZ concept, but CID, NER, MR, and some others are also good. If you don't want to go with any of those, then just stick to a plain old rectangular room with a good ratio for modal response, and treat it accordingly.
The first one is a preferential design with mainly architecture in mind,
If you want my advice: do not ever allow an architect to design a studio! Never, ever, under any circumstances! Studios are firstly and foremost
acoustical spaces with very specific requirements, and architects are not trained to produce those. I have been called in to "fix" the terrible, unusable, acoustics of several "architectural designed" places over the years, and they have always been acoustic disasters. Wonderful aesthetically, and structurally, for sure! Really nice looking, very attractive visually. But absolutely tragic acoustically. The best you can hope for in such cases is to deal with the worst problems, and perhaps make them acoustically acceptable, but never will they ever be acoustically great. Once the basic shape and size of of the room are fixed, there isn't much that can be done with acoustic treatment.
What you should do is to get the studio designed by an experienced studio designer, then perhaps, maybe allow the architect to "pretty up" some of the external aspects. But do not allow him to touch any of the acoustically critical aspects, such as room shape, room dimensions, locations of doors and windows, the HVAC system, internal room geometry, or treatment. The only exception is if you hire an architect who specializes full-time in studios, and nothing else. Those are the only architects who should design a studio, and especially a control room.
Now we are trying to think more of the acoustics of the control room, to build a really good control room, but we have to stick to that project as much as possible, architecturally speaking.
Unfortunately, if you have been given that shape to work with, and cannot change it at all, then you are pretty much out of luck, as far as having a good control room goes. Sorry.
Does someone has any suggestions or thoughts about the dimensions of the control room?
You can find the requirements for an acceptable control room in documents such as ITU BS.1116-2, EBU Tech-3276, AES-111 MÄKIVIRTA et. al., Genelec OY-2003, and several others. Those all show you exactly how the acoustic response of your control must be if you want to use it for serious work. To summarize: the floor area needs to be at least 20m2 for a stereo control room, or 30m2 for a multi-channel room (5.1, 7.1, etc.), the room must be symmetrical about the front-back vertical axis (in other words, the left side must be a mirror image of the right side), the shape must be either rectangular or a trapezoidal (Isosceles), the dimensions must meet the criteria "1.1 w / h ≤ l / h ≤ 4.5 w / h – 4", "l / h < 3" and "w / h < 3", the ratio must be within the Bolt area, the reverberation time must follow the equation Tm = 0.25 (V / 100)^^1/3 for the range 200 Hz to 4 kHz, rising by up to 300 ms at 63 Hz. and rising or falling by up to 100ms at 8Khz, there must be no early reflections within the first 15ms following the direct sound, and even then they must be diffuse and attenuated at least 10 dB for the range 1kHz - 8 kHz, there can be no flutter echo, there can be no tonal coloration, the frequency response must be as close to flat as possible, within +/- 10 dB for a typical home studio control room, or +/- 5dB for a high quality professional control room, the background noise level must not exceed the NR-15 curve under normal operational conditions, and preferably should not exceed NR-10, the relative levels of the individual speakers must be within +/- 3 dB from 250 Hz to 2 kHz, but above and below that they may very according to a curve that decreases at 2dB/octave in both directions, the absolute levels must be set to Lref = 85 – 10 log n ± 0.25 dBA (where "n" is the number of speakers), etc.
Those are the main ones. The fact that your architect didn't know about
any of the above is a huge big red flag, waving wildly. This is not a good sign...
Any suggestions about the polygonal shape of the CR
My suggestion would be to use a conventional shape that fits the above specs: either a rectangle, or a Isoscelean trapezoidal.
and the proportion between the wall?
Also as defined above. The relationship between the length, width and height of the room is critical to ensuring that you have good modal spread in the low frequencies, which is always the most problematic area in any small room.
We are really open to any suggestions to reach a good design for the CR!
My advice would be to scrap what you have at present, and start anew, with a completely clean slate and a fresh design based on acoustic principles, nor aesthetic ones. For a control room, aesthetics must, without any question, take a back seat to acoustics. That's not to say that it has to be ugly! Far from it: the interior decoration can be very beautiful. But it does not take first priority. Room acoustics are critical, and the decorative decisions must always be in harmony with the acoustics. No decorative piece can interfere with room acoustics.
So my advice would be that: Start over, but this time design it according to the standard and very well known principles of control room design. If you don't know what those are, or how to achieve them, then you have 2 choices: you can learn it yourself (realistically that would take you about 4 to 8 months), or you should hire a studio designer to do it for you.
That's probably not what you wanted to hear, but it is the truth. If there's one thing this forum is known for, it is "telling it like it is". No sugar coating. No punches pulled. You came hear to ask for honest opinions on your design so far...
The good thing is that with a space that size, there are excellent opportunities and possibilities for having a world-class control room and live room, with really great acoustics in both. However, that won't happen with the restrictions imposed by the architect.
- Stuart -
