Studio build for local college

Hi there, I have browsed this forum for awhile and now have a project that I would like to share and any input would be great! Long story short, I have taken on helping out a local college with a couple modules of their Audio Engineering and Music Production program. They have decided not to continue using a facility they had been renting out and build their own studio on site. So after visiting the facilities it was very clear that some work has to be done to make it a decent recording environment for the students. I have taken some measurements and fumbled my way through SketchUp to give a better idea of what I am dealing with. First off the description: There are 2 room that are beside each other to be used as the Control Room and Tracking Room. Tracking Room: 210"W x 208"L x 103"H Control Room: 210"W x 120"L x 103"H The rooms are constructed of concrete blocks for the walls. I have no idea as to if they are solid or hollow. The rooms are located in a single storey building. The floor and roof are concrete as well. There is a false ceiling hanging down 7 3/4" in both rooms and is the typical office building fiber-board panels with their metal grid. (not sure what the proper name is for these). The control room and tracking room are seperated by one row of these blocks (I will confirm, but they seem to be 8-10" thick). I did take a few pictures today to help describe the rooms as well. Control Room North East Control Room North West Control Room North West & Ceiling Control Room South Tracking Room South West Corner Tracking Room South East Corner Tracking Room North West Corner The photos were taken quickly, so they are not the best...but I can get better ones. Here is the sketchup file that I drew up... Now here is what I had in mind so far: The tracking room: -remove that blue draping (as it is not donig much of anything) -Isolation booth in SW corner -Floating floor with laminate, hard wood or T&G -Corner Bass traps (use a tuneable port) Not sure if they should have a hard or absoptive exterior...probably the later based on all of the very hard walls -building some triangular shaped absorber panels (maybe slat resonators) to help absorb in the room but also to break up the parallel walls...as it is almost a cube -Some form of baffling the HVAC vents (can be seen on the header above the door on the NW photo...as these are very noisy! Control Room: -Shelves and storage of equipment is moved out -Bass traps/broadband absorbers in the rear corners (maybe up front?) -Wall hanging absorber panels behing monitors, sides of room for reflections -Cloud above mixing position -Triangular panel on back wall to break up between front and rear walls The end goal is to provide a reasonable recording space. Based on budget and time constraints, this will not be a full blown build. I have access to trades that are emplyed at the college for any construction work that needs to be done (however I am sure they will need guidance/supervision with most of the project as it is not what they will be used to). For materials to work on both the rooms I was hoping to keep a budget of around $5000. With that being said some lumber & supplies I should be able to get the college to provide. There is more room if needed (budget wise), but also have to keep in mind that the facility also needs equipment to use in the rooms. Here was a layout I started to work on as a rough idea for a start:

Hi there "cmuller_21", and Welcome! :)

They have decided not to continue using a facility they had been renting out and build their own studio on site.

So are we looking at the space that they will no longer be renting, or are we looking at the space that they just built to replace it? If it is the former, then I guess that you just want a temporary fix until the new place is ready. If the later, then you have a problem! If that is the newly built facility, then you sure do have your work cut out for you! I'm afraid I don't have good news for you there. First, the control room dimensions are not good. A well-respected room mode calculator that I often use, comes up with this heartening message about your room "Room Ratio: 1 : 1.16 : 2.03. Nearest know ratio: A worst case scenario. 1 : 1.075 : 1.868". Not good. That room will have modal resonance issues. It fails two out of three critical tests used by the BBC for determining if a studio is usable, and also fails all three of the Bolt, EBU and IEC tests. Sorry to be the bearer of bad tidings, but you really should consider building a false wall in that control room to try to fix that. If you build it reduce the longer dimension by one foot, you get a somewhat more useful situation, but to really fix it you'd need to come down to 12.2 feet long and 8.4 feet high, while retaining the 10 foot width. That would put you the ballpark for Louden's fifth best ratio, get you passing both Bolt and IEC tests, as well as passing 2 out of the 3 BBC tests. Much better. That would be a usable space. Another option is to leave the length as-is, and install a hard ceiling at 8.3 feet. That would give you close to Louden's 6th best ratio. Not as good as the above, but not bad either. The other thing you certainly need to do, is to rotate the room layout: right now you have your speakers firing across the short axis of the room, which places the mix position (engineer's head) right in the middle of the room, in the worst possible acoustic location. So not only do you have serious modal issues, you also have your head right in the worst spot for hearing them all! The speakers should fire down the long axis of the room, and your head should be roughly 38% of the distance between the front and back walls, never at 25% or 50%. Rotating would mean that your window would be on one side, not straight ahead, but that's not a big problem, compared to how it is now. Turning your head when you need to see the musicians is not a big deal. OK, so all of the above is before you even think about treatment. No amount of treatment is going to fix problems such as the above. Next, the speakers are set up incorrectly: you have them turned on their sides, which means that the fields from the woofer and tweeter are offset form each other horizontally: so your ears are never on-axis to both at the same time! The speakers should be oriented vertically, with the tweeter above the woofer. The human auditory system is much less sensitive in the vertical plane than the horizontal plane, because our ears are on the sides of our head, not on our foreheads and chins! The speaker angles also seem wrong, but that's hard to judge from the photo. They should be angled inwards at 30°, such that the acoustic axis is aimed at the engineer's ears. That does not look to be the case. The speakers also seem to be too low: the acoustic axis of your speakers is supposed to be 1.2 meters off the floor. Note: "acoustic axis". Not the top, bottom or center of the cabinet. The manufacturer should be able to tell you where the acoustic axis lies on yours. Another biggie: those bookshelves have got to go! That's on your list, and you are spot on there: They are not helping your room acoustics in the least, and are probably doing all kinds of strange stuff: acting as diffusers for some frequencies, resonant cavities for other frequencies, perhaps even waveguides for others, in addition to the issues with the resonance of the wood itself, and all that edge diffraction going on at the corners: not good. The drop ceiling is also not doing much useful: I'd take it out and use that space for a cloud, and I'd probably make it hard-backed, to help with the modal issues a bit. Your basic plan for treating the control room looks good, but without fixing the dimensions, it won't accomplish a lot. However, I think you'll need much more absorption than you are counting on: theory says you need 391 sabins of absorption in that room, implying 391 square feet of perfect absorption. Your entire room surface area (walls, floor and ceiling) is only 822 square feet. Leaving out the floor, you have 647 square feet left. So you need to cover at least 60% of the entire wall and ceiling surface with absorption. By the time you allow for doors, windows and other things that cannot be covered, you don't have much space left. Anyway, not sure if that is much help to you! - Stuart -

Thanks for the info. This is the facility on the college campus. Definitely not ideal, however it is the only space that can be used...so I have to make it work in some reasonable fashion. All of the equipment is going to be gutted from there and other equipment installed...and yes the horrid bookshelf treatment will be removed and proper monitor placement as well. This was the first day of going in and seeing what was there to work with... I know that using the room length-wise would be best for a mixing position, however the one thing I do have to keep in mind is that it is meant to be a training facility...and being used width wise gives much better space for students etc...not that it has to be that way, but something I need to consider if there is a possibility of making it work. With all of that being said, I am looking for some guidance to make it workable..I know with its build constraints that I cant expect near-perfection...but I am sure it can be improved upon greatly from its current status. As far as how the rough approximate layout for treatment is...am I headed in the right direction?

The only way I think you could make it work width-ways is to use a very narrow desk, so that you can get the engineer's head out of the 50% location of the room depth (front to back). Since all room modes originate and terminate in corners, the middle of the room is the place where ALL of the modal peaks and nulls are at their maximum value. It really is the worst possible place to have the listening position. The theoretical best place is at 38% of the room depth. For a 10 foot room depth, that means your head should be 3' 9" from the front wall. That's where your ears should be: So you'll need a skinny desk that allows for that location. Considering that the speakers must go on stands behind the desk, and cannot be on top of the desk, that makes the desk rather narrow. If you can live with that small desk, then you can probably use the room width-ways. You will still need heavy treatment to deal with the modal issues, if you cannot change the other room dimensions. Just because your head won't be on the 50% location does not mean that you don't have modal issues! You still need heavy bass trapping, simply because it is a small room. Setting up width-ways also means that you cannot use the normal speaker geometry, with a 60° intercept angle: that would place the speakers too close together, and too close to your head. so you will have to switch to the 90° intercept, and live with the consequences. It's unfortunate, since the larger angle implies a narrower sweet-spot, and that's probably not what you need for a training room. For training, you should have the sweet spot as broad as possible, so you can get two or maybe three people in it, but that won't be possible if you set up width-ways. So I'd say that you can set up that way if you want to, as long as you are aware of the issues and work to minimize them as much as possible. For treatment, I think you have the right basic plan, except that the rear wall is going to need heavy absorption, not a reflective surface. Maybe 6 inches of 703 spaced 6 inches away from the wall, and angled out further at the top. You would want that as wide as possible, and going from floor to ceiling. (Or if you have a couch back there, then from the top of the couch-back up to the ceiling). I would make that to cover about two thirds of that wall width (one third each way form the center line), leaving space for bass trapping in the corners. Apart from that, I think you have the rest pretty much figured out. The cloud I would do hard-backed, to help break up your vertical modes a bit, and with thick absorption on the front (4" of 703). The other first reflection points could also be done with 4" 703, and the corner bass traps should probably be superchunks for that room, and as big as possible. I'd suggest 36" across the front (diagonal), but no less than about 28", minimum. And floor-to-ceiling, of course. I would cover all the bass traps and the ceiling cloud with 6mil plastic, for two reasons: to not kill too much of the high end, and in the case of the cloud to also prevent fibers filtering down onto your gear. But don't put plastic on the rear absorber, or on the side first reflection points. Then cover everything with acoustic cloth, to make it look nice! :) The room is too small to be able to use most types of diffusion, and I guess you already knew that, since you didn't mention any diffusion. Sounds like you have a plan! - Stuart -

Thanks for the advice on the control room! Very much appreciated. I will be back next week and decide which way to setup based on your comments. Regardless of which way it goes, shortening the length by 1' would still be a good idea? Now that the control room is out of the way (somewhat)...what about the tracking room? The idea is an iso booth in the room as well as treating that room (being that it is a concrete cube basically. Am I headed in the right direction with that?

Could you build an isolation booth on one end of your control room? 5x7x8 is a good size for a booth and you would have room left over for a nice storage area, or if you wanted the booth centered, you could put 2 small ones on either side of the booth. The tracking room dimensions are even more horrible unfortunately :roll: You will probably have to build another wall in there and either divide the space into two tracking rooms, or add another storage area. The good news is that you will ALWAYS need more storage area. We don't have enough, and it is always a pain to get everything put away.

I would cover all the bass traps and the ceiling cloud with 6mil plastic, for two reasons: to not kill too much of the high end, and in the case of the cloud to also prevent fibers filtering down onto your gear.

In this case would you need to use fabric that passes the blow through test? Good luck with the build! I am in a similar situation working at a small college and being stuck with what I have. In the end, I have decided "to decide" that this is a tremendous learning opportunity for my students! :wink: Most of us end up just having to make do the best we can. It may not be ideal, but there are always things you can do to make it better. My students are eating up the whole process. If your university policy allows, I highly recommend letting them do some of the building (under supervision from someone who will keep them safe of course!)

Now that the control room is out of the way (somewhat)...what about the tracking room? The idea is an iso booth in the room as well as treating that room (being that it is a concrete cube basically. Am I headed in the right direction with that?

Like Scott said: "The tracking room dimensions are even more horrible". Very true: it is practically square, and not much use like that. I think putting a booth in there might be an option, as that would certainly break up the modal paths. However, you don't have a lot of space in there: How many people do you need to get in there for a normal session? Based on that you can determine if it is worthwhile or even feasible to give up the amount of space necessary for a booth. I like Scott's idea of a storage room, as that would take up less space than a booth, and would not need to be isolated.

In this case would you need to use fabric that passes the blow through test?

For the fabric cover, yes, but not for the plastic film. The idea is that the plastic film should reflect highs back into the room somewhat, and allow only low-mids and lows through to be absorbed by the insulation. (that is in addition to stopping the fibers from falling out of the cloud). The problem with all small rooms is that they need a huge amount of bass trapping, but most forms of bass trapping also absorb high frequencies, so typically small rooms are too dead, with way too much high frequency absorption. The plastic film helps to keep most of those highs in the room, by not allowing them to "see" the absorption: they just "see" the reflective surface of the plastic, and bounce back: The lows, however, don't "see" the plastic at all, and pass through it pretty much as though it was not there. That's the theory. 6 mil plastic sheeting reflects down to around 600 Hz. If you need to reflect lower than that, then you need something thicker and more rigid, such as maybe thin plywood or melamine. Or even wood slats spaced far enough apart so as not to act as Helmholtz resonators. The cloth is just there for decoration, aesthetics: it hides the "ugly stuff" behind it. So yes, it needs to be breathable so as to be transparent to sound: it needs to let sound through at all frequencies, so it can be treated by whatever is on the other side. - Stuart -

Okay...so taking some of the advice mentioned...here was a rough sketchup of an idea for the tracking room. trying to keep the room to a useable dimension I figured 1:1.4:1.9 would potentially work. Lowering the ceiling to 8' and having the room 15'2.4" L x 11'2.4" W seems to do much better on the room mode calc and tests. This would leave space for a vocal booth and for a storage area. Just a quick rough idea done in SketchUp for the tracking room and some ideas of paneling for the control room if it is kept the same as it is now. thoughts? It does not leave a huge room, but it would be better to have a decent working environment for tracking in than the square cement box. For now it is drawn as a square, but the new walls would be angled for non-parallel walls. with the cavity on the left hand side of the larger tracking room, could this be used as a bass trapping area and allowing for more room in the tracking room itself? The upper left room would be for storage and the upper right as an iso booth...or the other way around. One more question: should the floor be built up? There is not a lot of height, however there are 2 very hard parallel surfaces with the roof and floor. Any suggestions? My thoughts were maybe raising it a couple inches, laying down hard wood and insulating between the cement and raised floor with roxul.

That looks like a decent improvement. One thing you can consider when figuring your modes is this: turn the room on end. Sound waves don't care which way is "up" and which way is "across", so you can interchange the "width" and "height" parameters. Sometimes that helps you find a ratio that allows you to make better use of height, if you have space available up there. It's always a shame to wast space in a studio: More volume generally sounds better, and more room height is always a good thing. So it might be worth playing around with some other options, where your room "height" is set to ten feet (which is really your width), and you vary the "width" parameter in the calculators between 8 feet and whatever the number is for the maximum space you have above you. It might turn up nothing at all, but you never know: you might find something even better than what you have now.

One more question: should the floor be built up?

Very likely it should NOT be raised. That is technically a "floating floor", and is very seldom needed for studios. But that doesn't stop a lot of people form building them anyway, and building them incorrectly, then wondering why the room sounds lousy... :) This might help to understand that issue better: viewtopic.php?f=2&t=8173

however there are 2 very hard parallel surfaces with the roof and floor. Any suggestions?

Exactly: That's why you need a cloud. Or you need to treat the ceiling directly, with absorption. Here's a curve ball for ya: You might actually be able to raise your ceiling a bit, then hang a hard-backed cloud at an angle to help deal with the modal problems. If you do that then you can no longer use the room mode calculators, or rather you can still use them but their predictions will not be totally accurate any more. However, the advantage of the higher ceiling and the angled cloud would probably outweigh the disadvantage of the room mode calculation issue. Worth thinking about!

My thoughts were maybe raising it a couple inches, laying down hard wood and insulating between the cement and raised floor with roxul.

That's more of a drum-riser concept than an actual floated floor, and you might well need a drum riser like that... but in the live room, not the control room, and not for the entire floor. There are good reasons for doing that... :) - Stuart -