Acoustic build-out in my control room.

[kcrummett]

Currently my control is just a bare room with a cloud(that hopefully can remain permanent) over mix position and some semi-strategically placed reel traps. My intentions have always been to build in permanent acoustical treatment to a have a truly purpose-built and professional looking/sounding control room. I've included drawings of my CR below as well as 3 REW "All SPL" readings of the room with all temporary treatment removed. If you would like any other info from my REW readings please let me know.

My game plan is to start with a simple build out, remeasure, listen, then reassess. But I have a few questions about where to start and what is an absolute must for this control room based on the drawings and REW images, if anything. As is, my mixes translate well outside the control room. The lowend is a little muddy but not overly abundant to my ears. But listening at the producers desk and on the couch is not so hot. And talking anywhere in the control outside of the position is painfully live and ringy which can make communication in the control room frustrating(mostly for me because I'm overly sensitive to the problem).

Is the following a good starting point, overkill or on the wrong path all together?

1.Building a fabric covered frame, filled with 4" rockwool and 2" of airspace left between the rock wool and preexisting wall, surrounding the mix position (front wall and sides including the first reflection points).

2. Soffits in the corners where the walls and ceiling meet in the front and sides as well as a much larger soffit/bass trap where the back wall meets the ceiling, all filled with pink insulation.

3. Creating the back wall the same as the mix position but with a, 8' wide x 4' tall QRD centered above the couch.

Here is a previous post regarding my studio. I'm not sure whether it's relevant or not, but I figured I'd include it incase it's helpful.
http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20358

Thanks in advance for reading this!

[Soundman2020]

Currently my control is just a bare room ....

Is it too late to change that? The diagram shows walls that are splayed unnecessarily, wasting a lot of room volume. There's probably something like 80 to 100 square feet wasted there. So if you can change that and get the walls straight again, you could improve the acoustics.

with a cloud(that hopefully can remain permanent) over mix position

There's also an angled section to the ceiling above the cloud, which also wastes room volume, so if possible it would be good to straighten that out as well. You don't need both a cloud and and angled ceiling. One or the other, and the cloud does not remove volume from the room, so it's probably the better choice.

I have a few questions about where to start and what is an absolute must for this control room based on the drawings and REW images, if anything.

I'm guessing that you are probably unwilling to correct the shape and size of the room, so the next best thing is to get it laid out correctly. First, clear the room. Get all of the furniture out, or at least puch it all to the back, leaving the entire front half tof the room completely empty.

It's a small room, and there isn't enough space to get your speakers far enough away from the front wall (it needs to be at least 7 feet away, and preferably more, to prevent SBIR artifacts from the front: 10 feet would be better), so your only other option is to push the speakers right up against the front wall, except for a 4 inch gap so you can insert a panel of OC-703 there. For those dimensions, your speakers should be 46" from the side walls, and therefore they will be 78" apart. Set them on very solid, very heavy (massively heavy!) stands, such that the acoustic axis is 49" above the floor. Now set up your chair on the room center-line, 98" from the front wall. That's the position where your ears should be. Set up a vertical pole 114" from the front wall, also on the room enter-line (in other words, 16" behind your head). Tape a laser pointer to the top of each speaker, directly above the acoustic axis, and exactly perpendicular to the front panel of the speaker. Rotate the speakers in place in their stands until both laser dots are hitting the exact same spot on the vertical pole. Now go back and double-check all of those measurements. Note that they all refer to the ACOUSTIC AXIS of the speaker, and not the top, bottom, side or center of the front panel, nor the location of the tweeter. Find out from the manufacturer where the acoustic axis is in your specific model. So the acoustic axis of the speaker will be 46" from the side wall, 49" above the floor, and aimed perfectly at the pole that is set up 16" behind your head.

Bingo! Your geometry is correct. That's the theoretical optimum setup. It might be possible to improve on that, by taking careful measurements with REW and adjusting distances and angles slightly, but that should be a pretty darn god spot.

Before you do anything else, do a complete set of REW tests like that: First calibrate REW fully, at 80 dBC for each speaker (which will automatically give you 86 dBC with both in, which is correct. Do three measurements: one with ONLY the left speaker on, another with ONLY the right speaker on, and a third one with BOTH speakers on. Post that MDAT file some place where I can download it, and post the link here.

With that in done, set up the desk in front of the chair so you can operate your gear comfortably from that position. Don't move the chair! Only the desk.

Now do another set of the same three REW tests, without changing any settings, and WITHOUT changing the position of the mic in the room. It must be in the exact same location, in all three axes, precise to within 1/4". Also post that MDAT file some place where I can download it, and post the link here. Make sure that each measurement in each MDAT file is labelled, so I know which is which.

My game plan is to start with a simple build out, remeasure, listen, then reassess.

Good plan!!!

The lowend is a little muddy

From the graphs, I'd say that is is more than just a little muddy! Take a look at this thread ( www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=20471 ) to see what REW results should look like in a properly done room.

but not overly abundant to my ears. But listening at the producers desk and on the couch is not so hot.

All three locations appear to have some fairly serious issues in various places on the spectrum. The room is going to need some serious bass trapping, plus a fair bit of other treatment, and tuning. However, you only posted the full-spectrum frequency response graph, so I can't tell you much at all about just how bad it is, or what you'd need to do to fix it. I'd need the actual MDAT file, with all of the measurements mentioned above.

1.Building a fabric covered frame, filled with 4" rockwool and 2" of airspace left between the rock wool and preexisting wall, surrounding the mix position (front wall and sides including the first reflection points).

That sounds a bit like you are trying for a LEDE approach! LEDE was abandoned as a room design concept a couple of decades ago, in favor of better developments, such as RFZ, CID, NER, etc.

At the front of the room, I would do at least 24" (and preferably 36"" superchunk bass traps in both front corners, plus the two panels of 4" OC-703 between the speakers and the front wall, and a couple of inches of OC-703 on the angled ceiling, plus the cloud, plus 6" of OC-703 on the first reflection points. Nothing more.

2. Soffits in the corners where the walls and ceiling meet in the front and sides

For what purpose? Why do you want soffits up against the ceiling? What do you intend to mount in there? Maybe that's for your HVAC ducts? Or something else? If so, that's a pity, as it would have been better to use that space for acoustic treatment.

as well as a much larger soffit/bass trap where the back wall meets the ceiling, all filled with pink insulation.

I'm not following: How can you have a soffit that is also a bass trap? Please explain. Bass traps need to have a large volume of porous absorption in them, but the solid, hard, rigid surfaces of the soffit would make that pointless. It's one or the other: you can't have both a soffit and a bass trap. If the soffits are intended for lighting or covering VAC ducts, or pipes, or some such, then it would be better to change the location of those, so that they are not in the corners, and you can then use the corners for bass trapping.

3. Creating the back wall the same as the mix position

You have major problems at the back of the room, so you are going to need major treatment there. I would recommend doing deep hangers across the entire rear wall, with smaller one towards the middle and larger ones in the corners.

but with a, 8' wide x 4' tall QRD centered above the couch.

You need a distance of at least ten feet between your ears and the face of any numeric-based diffuser. That refers to all "ears" in the room that need to do critical listening. Diffusers create lobed patterns of intensity, phase shifts and time shifts, and you need that ten foot distance for those artifacts to smooth over and become more uniform. If you have ears closer than ten feet to a diffuser, then even a small head movement can change the perception of balance, level, tone, and directionality. So either you'll have to move your couch ten feet in front of the diffuser, or you'll have to forget about diffusion. The room is border-line large enough to use diffusion, but you need to pay careful attention to seating positions for everyone who needs to be doing critical listening.

It would be good to see some photos of your room the way it is right now!


- Stuart -