Control room redesign

Great forum John! I’ve read your posts on several boards now, and I’m quite impressed. I’m hoping you and others here can help me with my control room acoustics. Sorry if this is long, but I figure the more info I provide up front the fewer questions you’ll have. A couple of years ago I leased a space next to the main video post facility in San Diego, which unfortunately is about 50 feet from the second busiest single-track rail line in the U.S. (East of our building). The I-5 freeway is the same distance to the West. I didn’t build the space, and the guy who did seems to have been a novice at best. He didn’t even put insulation in the walls (we cut holes and blew some in), and the main control room has parallel walls except for some weird angles and door placement that have always been problematic. I started out facing north like the previous occupants (see the old pictures on my site), then turned west for more symmetry, and now I’m facing east to be closer to the machine room, and so that ad agency clients can see the talent easier. However, the lack of symmetry in this spot is driving me crazy, and some notes (116-130Hz) are so out of phase between the two speakers (Genelec 1032A’s on stands) that the notes almost totally cancel (compared to each monitor alone). I have several 8’x4’ panels of 703 free standing by the walls, and I know I need more bass trapping, but I think I need to fix the symmetry problem first. I came up with a couple of designs that involve tearing it all down and starting over, but I have a hard time justifying the cost and downtime with the current economic climate – and since any soundproofing improvements would be expensive so close to the train. Also, the position of the bathroom and kitchen make it very difficult to expand the control room west. So I’ve come up with a couple of ideas that involve minimal construction (moving a couple of doors and filling in the gaps) but wanted to make sure I’m not missing obvious problems or alternatives. BTW, since this is a post facility, I need a TV monitor and center speaker in front of me above the computer monitors, and I need to have the ability to add surround speakers at 110 degrees (although I guess more people are starting to put them 125 degrees off axis). Also, I’m not totally against soffits, but I’m not sure I’m capable of building them correctly, and I might trade the Genelecs for Adams eventually depending on how they sound when I’m done with acoustic treatments. That said, I’d be interested in soffit mounting eventually, but for now would probably put bass traps in the corners behind the monitors. DDStudio1.gif shows the whole space, DDStudio2a.gif shows my current setup. DDStudio2b.gif is my first idea, which is to turn south and move the door to the west wall. The pros – it’s more symmetrical and I can get to the machine room again. Cons - there’s only two feet of space between the wall and the oh-so-popular 8 ft. purple couch. Also, my clients won’t be able to see the talent (the bottom of the window is 4 feet high). I’m kind of resigned to that, although they already think I’m crazy for moving my room around so much. DDStudio2c is my latest idea, which is the same except that I’d move the door to the wall between the hall and the machine room, and move the booth door out of my room and into the machine room also, making the entrance to the booth and the control room in the machine room. Pros – the two foot space between the couch and the wall doesn’t matter, isolation between the control room and booth would improve (which matters when my partner’s using the booth with his control room), and I could use all of the evil 10’x5’ alcove for hanger-style bass trapping. Cons – any time clients are there, the machine room door would be open, creating more computer noise, cabling issues, etc. I’m starting to think that would be worth it to get rid of the accursed alcove. Finally, just to confuse things more, my ceiling is an 8’ drop ceiling with 6” fiberglass on top, and for the 10’ width of the alcove there’s a real ceiling (bottom of the second story which is only in the front half of the building), but the eastern three feet above the drop ceiling is open to the top of the building, which seems to be at least 25-30 feet high (see DDStudio2d.gif). This is good because some of the bass must be escaping, but the train noise comes through the rollup door in the back, over the other rooms and through this gap. Luckily, this isolation problem doesn’t really affect mixing, but hangers in the ceiling would have to address this issue. So what do you think? Am I crazy, or will this work. Anything I’m missing? I have other questions about bass trap specifics that I’ll save for later. Guess I'll add the other gifs as separate posts. Thanks, J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

How it is now...

Plan1

Plan 2

And finally the ceiling configuration... Thanks again, J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

Couple of questions JJ Do you use the booth or the machine room for V/O - you said the client needs to see the machine room?? Do you use the Live studio?? there appears to be no window fro communication to that room. I suppose you need acces to the kitchen?? I assume the studio photo at your site is a pic taken from the south wall looking north with the window being the one into the booth?? cheers john

Do you use the booth or the machine room for V/O - you said the client needs to see the machine room??[/quote] If I said that I was mistaken. I meant the "talent" in the booth. [/quote]Do you use the Live studio?? there appears to be no window fro communication to that room. I haven't used it at all, personally. It started off as a lounge (with the pool table on the home page) and has evolved into a pretty good live room. My partner tends to record most of the drums, etc., but his room isn't adjacent to the live room anyway. I'm not as big a fan of windows as you seem to be - especially for mixing - so I'm fine with putting that off 'til later, but we do plan to seal off the live room from the freeway with a wall and a solid core door. Even so, you might be surprised by how little traffic you hear in the drum tracks, and despite my initial reservations, the drums sound damn good! Anyway, my focus is v.o., audio post and mixing music. [quote]I suppose you need access to the kitchen?? Yes, but no more than I need access to the front door and the bathroom. As long as there's a door out of the control room area, that should be good enough. [quote]I assume the studio photo at your site is a pic taken from the south wall looking north with the window being the one into the booth?? Correct. Old pictures re: my desk and speakers, but the space is the same. The wall I'm thinking of facing is the one behind the couch on the site. You can just barely see the existing doorjam in that picture. Thanks. It's exciting to have input from the master! J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

How about something like this?? cheers john

I thought of that, but I was worried that the wall behind the monitors would be too short at 7', and the monitors would be in the corners, which I thought was undesirable. One advantage of facing south was freeing up both corners behind the monitors for bass trapping if I was using stands. In your design it appears that there's only trapping on the left side, which might not provide the symmetry I'm looking for at the mix position. How would your design work if I decided to soffit mount later? Would there be room for that? Also, since you added doors at the north end, there wouldn't be hangers in the former alcove, correct? I assume that was left over from my drawing. Thanks, J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

you couldn't soffit mount in this layout and yes those bass traps were left over from your drawing. cheers john

Thanks John. I'm thinking that the quality of the mixing environment is more important than my clients seeing the talent while sitting on the couch, especially since they can see the booth if they're next to me in a chair. So using mixing/acoustics as the main criteria, is facing south the best way? And would this make soffit mounting easier now or in the future? For me, symmetry and bass trapping (relatively equal RT60 across the frequency spectrum) is the key. Thanks again, J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

Yes JJ - if you want to soffit mount and don't mind notseeing directly into the booth then south is the way to. :) Don't forget the door! it would be better on the west wall or through the rear of the control room. cheers john

Great, John, thanks! Good to know I'm not completely crazy. I have some specific questions about bass traps, etc. that I'll probably post in the construction section. But while we're talking about free-standing monitors near corners, I'm wondering what bass traps are best in the corners behind monitors on stands. I've seen you recommend slot absorbers, but are there situations where the low bass extension of hangers/panel traps might be better - especially since the corners have so much low bass? Also, without soffit mounting, it seems that it would be better to have a non-reflective surface so close to the monitors. I plan on making traps appox. 2'-3' on each side for the corners. Is that big enough for hangers? Could I make them portable as long as they're airtight? So many questions... Thanks so much for your help, J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

In addition to my questions about bass traps behind speakers on stands, I have a new and bigger problem re: turning my control room orientation to the south. Yesterday I turned most of my stuff (including the big couch) in that direction and put the Genelecs where I think they would be - about 6' apart, close to the south wall, equidistant from the "new" side walls @ 3' each. I didn't move my desk, but it's quite small with only two 17" monitors for Pro Tools. I put a panel of 703 between the "east" monitor and the south door, but otherwise the sound treatment was the same as my current position. What concerns me is that the two monitors were nowhere close to symmetrical in bass response. In fact, the peaks and dips were almost opposite of each other above 80hz. The range between 80-140 hz was 10-15db louder on the monitor on the east wall! (In other words, the western one had more cancellation and dips in this region). And both monitors together were much worse than my current position in the 200-300 range, adding a lot more mud than I hear currently (the current ringing in this range is the whole reason I started down this path). BTW, I switched the monitors with the same results, so it's definitely the room. I assume that this 200-300 range needs absorption for more even response throughout the room. What concerns me is the lack of symmetry, since this is the whole reason I'm thinking about moving doors and filling in walls. So I have a couple of theories about the assymetry of bass response on the south wall. Which do you think is likely to be the _main_ cause of this problem? 1) The door is still in the south wall behind the east monitor. Also there's a sliding door on the east wall into the machine room. I'm sure this is having an effect, but is it the main one? 2) The room is shorter on the eastern side because the booth sticks out into the control room. 3) The eastern 3' of the control room is under a much taller actual ceiling (above the drop ceiling). See the last pic in my first post above. The "real" ceiling is at least 10' higher on the eastern side than the western one. If #3 is the main problem, then I'd have to close the eastern gap above the drop ceiling, which would be more expensive, could remove a possible current outlet for excess bass, etc. If #2 is the problem, even the additional ceiling construction wouldn't solve it. So what do you think? Is it going to take more construction than I previously thought to make the room symmetrical in the bass region, or will moving the south door and filling the wall fix most of it? Does a drop ceiling with 6" of loose insulation on top still let most of the bass out into the cavity above, and can two monitors 6' apart have wildly different bass response because of it? Thanks again! J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

1) The door is still in the south wall behind the east monitor. Also there's a sliding door on the east wall into the machine room. I'm sure this is having an effect, but is it the main one? 2) The room is shorter on the eastern side because the booth sticks out into the control room. 3) The eastern 3' of the control room is under a much taller actual ceiling (above the drop ceiling). See the last pic in my first post above. The "real" ceiling is at least 10' higher on the eastern side than the western one. If #3 is the main problem, then I'd have to close the eastern gap above the drop ceiling, which would be more expensive, could remove a possible current outlet for excess bass, etc. If #2 is the problem, even the additional ceiling construction wouldn't solve it.

I'd suspect both doors are causing the problem. They are basically panel absorbers with no absorption:) How thick is the glass in the sliding door?? 2) shouldn't be a problem I don't believe the extra ceiling height should effect the low end as much as you say it varies. I suspect both doors. But if there is that much variation why not stay where you are?? at least you can see into the booth:) You coiuld build a reciprocal wall on your right to match the booth window wall and build another wall across the north end to create symmetry. I really think you are in need of more acoustic treatment generally. cheers john

How thick is the glass in the sliding door??

I haven't measured it, but it's pretty flimsy and certainly isn't airtight. I was thinking of replacing it with a solid core one if I faced south.

I don't believe the extra ceiling height should effect the low end as much as you say it varies. I suspect both doors.

Hope you're right. Guess that means the ceiling tiles stop the bass pretty well.

But if there is that much variation why not stay where you are?? at least you can see into the booth:) You could build a reciprocal wall on your right to match the booth window wall and build another wall across the north end to create symmetry.

That was actually my first plan (not posted), but I thought it would make the room too small and short. One variation was to move the south wall 4' further south, and to convert my alcove into the hall. However, where I am now might be worse (see phase problems below), although maybe the south wall mirroring the shape of the booth wall would fix it.

I really think you are in need of more acoustic treatment generally.

No doubt about that :) I was just hoping to make the room more symmetrical, too. What worries me is how out of phase the two monitors are (and even one monitor in two places). Panning the recorded output of the monitors hard left/right and running them through a phase torch shows some wicked anti-phase in both positions. At the proposed south wall location the two are out of phase at 82Hz and the entire range between 120-136Hz. The signal actually progresses counterclockwise through the anti-phase and reaches the top again around 160Hz. Remember that the monitors were equidistant from all three walls and drop ceiling in the vicinity. My current position is worse. It has the same problem over two ranges - 87-120Hz and 161-178Hz. Notice how the response at the two positions are the opposite of each other? I also performed the same test in a supposedly well-designed symmetrical room, which has problems because of the all-dead acoustic treatment, but almost never goes into anti-phase and is much more consistent. These phase issues seem to be realtively independent of the volume differences between the two monitors - although, of course, they affect the volume of the summed signal a lot. So I might still want to turn south, but I'd be bummed if it turned out that the difference in the height of the shell made it impossible to have symmetrical bass. What do you think of the phase problem anyway? Is this normal? I'm thinking that no amount of absorption at these frequencies would fix the problem, so symmetry is key. Thank you so much for your patience and help! BTW, I can't give you Bush's head on a platter because the line's too long and the platter would be really big (or maybe really small) :) Thanks! J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com [/quote]

Hope you're right. Guess that means the ceiling tiles stop the bass pretty well.

No the bass would go straight through them but it still shouldn't cause out of phase components.

Panning the recorded output of the monitors hard left/right and running them through a phase torch shows some wicked anti-phase in both positions. At the proposed south wall location the two are out of phase at 82Hz and the entire range between 120-136Hz.

I'm not sure what you are doing here - recording them with what and how?? ...could you elaborate?? cheers john

I used Pro Tools' signal generator plugin to play sine waves in 4Hz increments betweeen 20-300Hz. I recorded the result as audio so it never changes. I then recorded the output of the monitors alone and together with an Audio Techinica 4050 (no Earthworks at the moment) in Omni mode, no hi-pass, etc., at the mix position. Pan them hard left and right and look at the result in a phase torch plug-in (circular, X/Y grid). Duplicating the track with the orginal tones and hard panning the original left and the duplicate right shows perfect unchanging phase. Comparing the monitors on the south wall to each other shows them to rarely be completely in phase but almost totally out of phase in the range of 120-136. The output at my current position has much larger sections of the bass spectrum out of phase between the two monitors as noted before. You can hear it in headphones, too. Interestingly, comparing one monitor's output - or both together - to the original file (after time adjusting) shows that the phase constantly/sluggishly rotates counterclockwise as the tones rise in pitch. This is true in my room and the other control room I tested. What's different between the two rooms, however, is that the monitors are out of phase with _each other_ in my room, whereas the other room is much more phase-coherent throughout the range I tested. In both rooms phase between the two monitors improves above 200Hz or so. Thanks, J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

No the bass would go straight through them but it still shouldn't cause out of phase components.

O.k., but forgetting phase for a moment, would the bass escaping above the east monitor account for less cancellation compared to the west one, or does the bass from the west monitor go up there, too? The east one had quite a bit more bass overall, usually 3-8db (although at a few frequencies it was the opposite), so it seems like the west one had more cancellations from bass buildup. In fact, at 186Hz (which doesn't seem to correspond to a node), the west one had a dip that was 16db quieter than the east monitor. Of course as you mentioned, it might be caused by the doors. Sorry for all the questions. Just measuring twice and cutting once. :) Thanks, J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

JJ you are chasing your own tail. You've got a room that has no apparent acoustic treatment and you are finding ambiguities in the rooms response. You would expect that which is why you need to look at proper room acoutic treatment - that's why people treat their rooms. :wink: cheers john

Understood, but it's not clear that this would fix the asymmetrical response I'm getting. Does the addition of symmetrical bass trapping in a room suddenly erase 8-16db differences in bass response between two monitors? It seems that bass trapping would reduce the problem, but the source of the asymmetry is elsewhere. My concern is that even with more treatment, and even with the doors moved to more acoustically neutral locations, the difference in "real" ceiling height would still make the two sides noticeably asymmetrical if I faced south. I'm worried about spending hundreds/thousands of dollars and seeing little improvement in symmetry, which is why I'm asking experts for their opinion. I read a lot of audio/recording forums almost daily, but this is the first one I've posted to in years because I respect your opinion and believe that acoustics is more important than all the gear in the world. I know that my place has problems acoustically, and I'd abandon it in a second except for the fact that there's built-in work from next door. Not enough work to justify a massive overhaul, but enough that I need to fix the acoustics as best I can. So I'm stuck with finding a solution that's the best compromise between sound quality and price. I plan to build bass traps per your specs once I understand the details better. You've convinced me that Ethan's bass traps might not be the ticket, and that slot absorbers and hangers are the way to go. But saying that a room with 703 panels covering almost every vertical surface has "no apparent acoustic treatment" seems a little harsh, don't you think? Thanks again for your patience and understanding :) J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

But saying that a room with 703 panels covering almost every vertical surface has "no apparent acoustic treatment" seems a little harsh, don't you think?

I'm sorry JJ - I didn't realise that that was your situation with the 703 - I thought you were about to add treatment.... My Bad. Could you describe the ceiling structure in a bit more detail - your drawing doesn't quite give a realistic picture :) I syour room open to the higher ceiling over the rest of the building?? cheers john

I'm sorry JJ - I didn't realise that that was your situation with the 703 - I thought you were about to add treatment.... My Bad.

No worries :) I consider myself fortunate to still have your attention after so many long posts! My control room has a drop ceiling over the entire length and width of the room. The bottom of the second floor is above that about 2' higher and runs the entire 20' length, but the width of the second floor only runs for 10' west to east. So the eastern 3' above the drop ceiling is open to the ceiling of the building, which is at least 15 feet above the drop ceiling. This back area used to be a warehouse space, and we've often thought of using it for a larger live room eventually. In my first post, the final drawing shows this visually. The ceiling in control room A is the drop ceiling, then the second floor is above it. I'm worried that bass escaping through the drop ceiling on the east side makes the east and west sides assymetrical in the bass. But if I closed it off, more bass would be trapped in the room, making the bass problem even worse. The subject of the drop ceiling is even more complex because I'm still trying to figure out the best way to treat it. If I try to hang 703 from the entire drop ceiling I'm afraid the drop ceiling frame won't support it. What do you think? What about the possibility of replacing the ceiling tiles with 4'x2' rectangles of 703? Otherwise I'd have to hang them from the bottom of the second floor, which means getting rid of the drop ceiling and closing off the eastern gap in the "hard ceiling" with drywall. At that point, maybe it would make more sense to use hangers and a false cloth ceiling, and take the 6" fluffy insulation that's currently on top of the drop ceiling and attach it to the bottom of the second floor ("hard" ceiling) for high frequency absorption. It depends, I guess, on whether a 2' gap is big enough for hangers. What do you think? Would hangers, say, 18 inches by 8 feet have enough mass for at least some upper bass absorption? Also there would be some challenges with air ducts since they're above the drop ceiling, but hopefully I can figure that out on my own. One more problem with getting rid of the drop ceiling is that the ceiling would then be 10', or half the 20' length of the room. Since this room is mostly rectangular, room nodes do seem to have an effect. On the other hand, if the bass is passing right through the drop ceiling, maybe I already have a 10' ceiling as far as bass is concerned. And if I put hangers in the 5' deep alcove at the north end of the control room, maybe the room acts as if it's 15' long... I think I 'm getting dizzy. :) As you can see, you've got me thinking a lot about acoustics. Many thanks! J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com

As you can see, you've got me thinking a lot about acoustics.

Well that's good :) I'd close off that huge cavity up there first. You can then treat the bass once it's contained. You could hang false ceiling panels by chains that go through the drop ceiling and attach to the actual ceiling. These could have a plywood backing on a 4" x 2" frame with 703/cloth on front. (clouds as they are sometimes called) They could then be angled with the chain length to break up the floor/ceiling parallels. Yes hangers in the rear would help a lot, and the room would still be 20ft. You could copy the angle of the booth window on the opposing side also. cheers John

I'd close off that huge cavity up there first. You can then treat the bass once it's contained.

Thanks. Not the answer I was hoping for, but pretty much the same conclusion I had come to. So about the clouds - do you think I need to keep the drop ceiling to keep the height at 8' for node reasons? Otherwise between construction on the "gap" and trying to cut holes for the chains for the clouds and the hangers in the back I think I'd rather get rid of the drop ceiling altogether. If the nodes are the reason, then maybe another wall in the hanger area to make the length, say, 18 feet? That would still leave 3ft. for hangers. Thanks again. I'm almost done with this thread. Soon I'll just be asking annoying bass trap questions! :) J.J. J.J. McLeod Different Drummer Studios www.differentdrummerstudios.com