Step By Step Studio Tuning

I'm nearing the end of the construction phase of my studio and I'm seeking advice on how to approach the treatments after the paint drys. My build thread on on the "Studio Construction" forum. In short, I've got a roomy control room, nice drum booth, good sized vocal booth, and a rather large main studio area. My isolation should be taken care of. I guess what my question(s) come down to are: 1) Which room should I start with? Control room first then use the equipment there to tune the rest of the rooms? Does it really matter where I start? 2) Should I get ETF and measure each of the rooms before I do anything else? Are there some basics I should start with since they are ALWAYS going to be there? 3) When I have multiple options for treatment (i.e., absorbtion (sp?) vs diffusion, what criteria should I use to determine which way to go? Cost? Looks? Space available? 4) Can I realistically completely treat the control room (so I could start to get a little revenue!) before I attack the other rooms or will there be some interaction? I know it's lots of questions but I don't know if I've seen a step-by-step explanation of what to do after you've finished basic construction. Thanks! Len Morgan

Len, before I start I'd like you to post an updated plan of just your CR, showing actual measurements from every surface - include distance wall-to-wall at the very front where it's splayed, distance along the centerline where the splays STOP, and then post a second copy with your proposed locations for mix desk, any furniture, producer's desk, etc, if you know what you'd like in the room at this time. Please rotate the CR drawing 90 degrees from the way it's presented in your first page floorplan, and size it so it's 750 pixels wide (the long dimension of the room) for best detail. While doing this, think about how much depth at the rear of the room you're willing to give up if it will drastically affect the room sound, and whether you will have carpeted floor or not (sorry if it's been mentioned) You can definitely do your CR first, there will be little to NO interaction between rooms because of this. That's already been decided by your wall/ceiling construction, and won't change whether one or all rooms are treated. I'm seeing quite a bit of parallel wall surface, and from all your pix it looks like the ceiling is also parallel to the floor; please confirm or explain if it's not the case. Your live room also has a lot of parallel surface; the booth will alleviate some of that, and if you're willing to build an angled slat resonator across the east wall of the LR that comes out to the drum room window on the north end, and terminates in the corner of the south end of that east wall, all that will be left is parallelism between floor and ceiling. I don't remember seeing actual numbers for ceiling height; it will help if you can also provide those for each room (unless they're all the same) For a start on your CR, you can temporarily ignore the slanted parts of your walls on the south end, and the little alcove on the north end; see if you can implement the methods I show in "are my speakers in a null", in this forum, using the rough dimensions of the room as if it were a rectangle. Keep in mind that the front of the room will change because of the splays, but this method will help you locate your desk at least. Oh, are you planning to soffit mount your speakers or not? And how high will they be, if you know at this point? There are some things of interest in Newell's Recording Studio Design (check your question in the "null" thread) on pages 410-420 you'll want to check out on that subject. Crash time, gotta run for now... Steve

Will do. I'm going to be going down to the studio today (wife has to work until 4:30 so we're going to "do" Christmas later this afternoon) and I'll make some measurements. One quickie though: You said to make the new Control Room drawing 750 px WIDE. Isn't 700 the official limit for this forum? len

John says both 700 and 800 pixels here and 700 pixels here... And Steve says between 700 and 750 pixels here. I tend to go with the lowest number, just to be safe. My new (work-issued) laptop has a screen width of 1680 pixels, so it matters not to me! :P --Keith :mrgreen:

Yeah, 800 doesn't cause much scrolling on a 1024x768 screen, but since most people always "fudge" the speed limit...

Ok, here's the dimensioned pictures of the finsihed room sizes. To answer your questions, Steve: 1) I am willing to give up as much space as required on the back wall (and side walls too for that matter) to get the best possible control room. I would like to be able to have other people in the room hear basically the same thing I will at the mix position. My mixing/patch desk will be about 6 feet wide and 50" deep. It's fairly flat but I would like to mount three LCD screens in it and not have them interfere with the sound (I know this may be impossible). My eyesite is not good enough to mount them over the window (and I'm ALREADY wearing bifocals). It would be nice to have a small couch or fold out footon at the back of the room (in case a session goes late or I make another attempt at Russian and my wife misunderstands me :-( ) This is not necessary but a nicety. As to carpet, I've always heard it's bad news. If it helps, I'll do it. Currently there is commercial grade vinyl tile on the floor. I could go for wood laminate some time in the future over that but not until I've got at least a little revenue coming in. Ceramic tile would doable if that was better. As a general consideration for the main room, since it is so large, it might be nice to have it some what accoustically variable or have a live end and a dead end but I'm not set on this either. Basically, I'm putty in your hands. :-) Ceilings and floors of all rooms are parallel. Sorry, I didn't have much choice within the confines of the shell I had to work with. Ceiling height in all rooms is right around 95". There is a "beam" that runs down the middle of the main room that encloses the posts that hold the roof up (see the pictures in my studio build). I didn't measure the beam but my guess is it's about 8" high and 18" across. I was not originally planning to soffit mount my speakers but changed my mind a month or so ago. Unfortunately I had already built the framing and had to live with the splayed walls at the front. My plan is to finish the CR and then build another soffit wall (I really think I'm just mounting them in the wall flush with surface rather than a "real" soffit mount which as I understand it is free standing and decoupled from the walls of the room). This will require two new walls that will start at the edges of the window and come inside the currently angled walls. I should have just enough room to get my speakers in there. They will be raised (or not raised) as needed for the best listening conditions I can get. I am not married to any particular design features (except the doors and windows since they'd be a little hard to move at this point). I'll give up whatever space I need to get the best possible sound. For example, I don't mind giving up the main room window to SE corner for a slat absorber as you suggested. Let me know what you think or if you need more to work with. len

Len, those are scans? Were they originally electronic, and if so what program? Any chance of getting a DXF file of each? Thanks... Steve

I'll give it a try. The program I used was Punch Software's "Architect 3000" (available at Walmart). You'll have to use the measurements from the scanned drawings because the program can't seem to decide whether to use inside, center, or outside dimensions. All of the measurements I provided are actual measured finished ones. len

Got 'em; hopefully night shifts will be slow so I can get a head start... Steve

Steve, I know you are very busy but I'm getting close to finishing the rest of the construction/painting so I'll need to start treating the control room. I think I've got my vocal booth taken care of. I got a box of Auralex AudioTile which should be enough for an 8x5x8 room. The control room is next. At this point, I want to start at the front and work my way back. The reason is I want to put the glass in before I do any major testing and I'd really not rather have hamers and such anywhere near new expen$ive glass!!! Remember, I'm the one that sealed myself in the vocal booth while drywalling. len

OK, so you ARE going with soffits now - is that the latest? What are the dimensions of your speaker boxes? Steve

Speakers: 22"H x 10"W x 10"D I'd like to leave an opening (I'd like to use a baffle over the front of the speakers) big enough for larger speakers although I know that presents problems because of the depth. See what you can do. Again, as always, I appreciate your looking at this and advising! len

Steve, I've got a little more info to add to this. After penciling in my "soffit" walls at the front of the control room, it looks like I'm a little shy of being able to build a couple of cinder block pilars to mount the speakers on (so that they won't rest anywhere on the wall itself. If you look at the scanned control room drawing (the one with the green highlights on it), you can see that the two splayed walls were probably a mistake (too late to fix now. The one on the right side was probably necessary because of a post that would have made for about a 20" door to get into the main room. Since I had to angle one wall, I decided to make them both the same. In order to get the proper 30 degree angle my sofit wall has to come out away from the CR walls and (currently) about 10" in front of the window. If you can picture this, where the window is, a "wall" will come straight out about 10" and then angle off towards the splayed walls on either side. This will give me a little bit of a tunnel effect as I look through the window. I'm going to have to increase this tunnel to about 12" deep if I want to be able to get two cinder blocks side by side behind the wall. At the top of the window, a false wall (filled with insulation and covered with cloth) will angle up toward the ceiling at about 30 degrees. It will reach the ceiling before it reaches the mix position but I had already planned on a ceiling cloud. So, this brings up the following questions: 1) Is the "tunnel" going to present a problem (accoustically)? 2) Should the parts of this new wall/sofit that are not part of the speaker baffle be filled with insulation and covered with cloth or a hard surface like plywood or MDF? 3) Is putting an absorption wall angled from the top of the window going to do me any good or would I be best off to just take my two "sofit" columns straight up to the ceiling and leave the middle area above the window alone? 4) Since I'll have to build out about a foot from the front of the window (at least on the lower section, would it benefit me to also move the glass out of the wall and increase the distance between the two panes? I'm thinking that the total gap between panes would then be about 2 feet. I realize that I'd need to make the new build out stronger if It needs to support the glass. Of course, that also means I'll have to do something over the window too. 5a) Sort of switching topics for just a moment, the side absorbers John designed (which I plan to add on either side of the mix position appear to have an 8" x 7' flat face to the speakers if I'm reading the drawings right. Wouldn't this give two flat hard areas that would immediately reflect sound back to the baffle and then to the mix position? 5b) The drawing indicates that the back "wall" of the absorber is 7' tall by 4' wide: Why not 8' which is how plywood is sold? Is that a Canadian 8' that looses a foot due to the exchange rate? :-) I'm sorry for all the questions but I'm getting close to being stopped on the CR until I can get a little direction as to how to proceed. Thanks, len

I thought I'd snap a photo of the front of the control room to give you a visual idea of the area I'm talking about. len

Steve, I thought I'd post a drawing of what I'm thinking of adding to the room (particularly the front of room) in the hopes of a "go/no go" so I can start building. Note that the orange at the front of the control room (bottom of picture) is the soffit wall. It starts at the floor and the "table" in the middle goes up to the bottom of the window. The "speaker columns" continue going up. When you get to the TOP of the window, my plan was to come out at an angle from the wall to the ceiling (probably 3 feet or so) and it would be insulation/cloth. The speakers would be sitting on two cinder block "pilars." The reason I'm pushing a little is that I pretty much have to build these pilars before I start putting the wood together. Pretty tough to do the other way around. :-) len I can't add the scan because it's too big. I'm going to try and point to it

Len, I finally had to regenerate your drawing from scratch, then convert to jpg - try as I might, I can't find a way to get 16" square pillars into soffits, far enough away from the window to give anywhere near large enough baffle size. I'm attaching the sketch (not dimensioned, but scaled) - the smaller squares are 10", the larger ones 16", window is 5', distance of the two splays is 53" longitudinally, with 23.5" narrower each side of the front wall. Moving speakers any further apart would put your mix position too far back in the room, and in fact this way puts it almost dead center :cry: I'm thinking maybe change away from a 60 degree setup here, and move the outer ends of the soffits up the walls toward the rear of the room a bit to get better positioning of the mix position and still allow later upgrade on speakers?? John has used up to 90 degree angle, although that will make imaging more touchy. Other than NOT soffiting the speakers, not sure what to do with this one... Steve

Steve, Thank you very much for the reply! I DID manage to get the 2 8x16x8 blocks in the space but I neglected one factor: the size of the baffle! Is there some minimum size I should be aiming for? My listening position (as I've penciled it on the floor) is just about where you've got it (i.e., right about 1/2 way back. This did cut into the space a little but actually gave me great visability from the mix position out the door to see who's coming in the front door. In the last couple of days, I've managed to get my hands on a (used but fully functional) video system so I can mount a camera right above the door to the main room which has line of sight to the front door. :-) So, maybe I need to do this backwards. What minimum size baffle to I need to be effective? Based on that, I can narrow the angle (from 60 degrees) to move the mix position forward AND get a big enough baffle. As a thought, as I understand it, the reason for the baffle is because when the sound wave hits the edge/corner of the speaker cabinet, it re-radiates and creates a "phantom" wave as if there was a driver on the corner/edge. What would be the effect of curving the window side of the soffits so that instead of creating a "hard tunnel", it gently curved? I could even do the same on the other side (the splayed side) so that the shape of the sofit from the top would look like a shallow "S." I'd have no "corners" to worry about. The window side would be a convex curve but the other side would be concave which might cause a problem. I've never seen this done and maybe there's a good reason for that. It's a little extra wood work but perhaps workable. I'd appreciate your thoughts, particularly the "big one": what is the minimum baffle width/speaker width ratio to make the baffle worth the effort. Thanks again!!! len

Radiusing your corners at the window will help with higher frequency diffraction effects, but won't fix the baffle size problem; I need to know which speakers you'll be using and what their published lower cutoff frequency is first, but for a lower Fo of 57 hZ, total baffle width should be 80 inches. Less than that will work, but that's optimum. The formula for finding baffle width in inches is Wb = 4560/Fo, where Wb is baffle size in inches, and Fo = the low cutoff frequency of the woofer. HTH... I'm still working on options for this... Steve

Steve, The speaker specs are 30 Hz - 25 KHz (with the -3 dB points at 43 Hz and 23 KHz). I see four and a half possibilities: 1) Change the angle by moving the end point of the baffle to the joint between the splayed wall and the wall perpendicular to the front wall. I tried this on the floor and if I use only one cinder block, laid sideways (long side along the baffle wall) I get 53 1/2" across the front of the baffle (and 11" out from the front wall as before). 2A) I have a pair of M-Audio BX8s to use instead. These are however DEEPER than the Polks, have a rear bass port, and get pretty warm. They also have an angled front on the top of the cabinet that makes the baffle more of a wood carving if I'm going to get everything flush. 2B) I could mount either one of these monitors on (or just in front of on stands) the mix desk (i.e., NOT in a baffle wall) and put a bunch of absorbtion in the "corners" behind them. 3) This is the most drastic - I could tear down the front (splayed) section of the control room and rebuild it in place WITHOUT the splaying. This would give me a lot more space behind the speakers (and is probably what I should have done in the first place although it causes other problems like the door to the main room would have to go down to 26" or so). As you can imagine, this is probably the least desireable option. 4) Add a subwoofer to the system either on the floor between the monitors or above the window. I'm not sure exactly what the baffles do except to stop re-radiation of the lows from the edges of the speakers. I want this room to sound good so I'll do what's necessary. I guess one other option I have would be to turn the control room 180 degrees and have the window at my back. I'm kind of stuck here. I thought I'd done everything right but I guess I was wrong. :-( len

I guess one thing I should add is that this baffle wall is only the BEGINNING of the treatment I expect for the control room. I was also planning on the side absorbers and a slotted wall (shallow inverted "V") at the back wall and some sort of cloud above me. Since I've seen those on almost every reasonably sized control room, I assumed they just came with the territory. Does that change the baffle wall problem any? len

A few more thoughts... After reading the article you referenced in another thread about the baffle step response, I came away with the following: 1) Any "errors" caused by the BSR can be fixed with a correction network in the speaker path. 2) The real world response (as opposed to the theoretical) is 3 to 4 dB loss of bass. Might it not be possible to "get this back" by using LESS LF absorbtion? 3) It would seem to me that ANY increase in size of the front of the speaker cabinet is an improvement. I believe the only two conditions mentioned were speakers in free space and speakers with an infinite baffle. After taking one of my monitors and placing it my cardboard "cinder block," I don't see why I need two of them. One of them should be more than stable enough since I'm going to have to have some sort of top plate that is anchored to the pilars since the monitors will have to be pushed forward (and therefore over the front edge of the pilar) in order to get flush with the front surface of the baffle. This will give me a little more room behind the baffle wall. I guess what it comes down to at this point is how bad could putting as big a baffle as I can fit into the space I have. By changing the design completely (like putting lots of absorbtion BEHIND free standing speakers), will I gain substantially? I know whatever solution I come up with will have to be a comprimise from perfect but isn't that pretty much the situation we are ALL in? len

Your speakers will need to overhang the pillar by a bit anyway, so if you build a single stack pillar, FILLED with concrete and rebar it should work. One downside is that ideally, the ENTIRE pillar and speaker should comprise the second mass in a m-s-m system in order to best isolated LF from structure - this would mean a fairly "tippy" pillar, with only an 8" wide front-to-back dimension, and could cause some problems - Speakers can move slightly when reproducing strong bass (Newton, an' all that) so might rock enough to contact the soffit and rattle. ANY speaker mount needs to isolate from structure in some way, otherwise (since speed of sound in solids is several TIMES that in air) you get a "pre-echo" radiated from surfaces close to you (like the desk) - similar to early reflections, only even EARLIER :cry: Few speakers are heavy enough by themselves to work well by placing elastomer pads right under the speakers; this usually causes the m-s-m resonance to be in the audible range. That's why it's better to "spring" the entire speaker "pillar" and hard fasten (straps or something) the speaker cabs to the pillar, so the act as one mass in the m-s-m equation. I'll try to find some time tonite (if work is slow) to play with these new dimensions, wish me luck... Steve (peaked rear absorbers aren't necessary if you don't use slats; the peak is mainly to keep rear wall reflections at higher frequencies from coming back to your ears) Side absorbers shown at the SAE site are more for portable treatments - all you should do before serious listening in your CR is to use flat, stood-off absorbers at sidewall first reflection points and cloud on ceiling, and a good deep rear absorber such as Newell uses in the Hidley-type "non-environment" rooms. In fact, you should listen FIRST so you'll appreciate each step of the treatment...

Thanks Steve. Good luck tonight.

knightfly wrote:

ANY speaker mount needs to isolate from structure in some way, otherwise (since speed of sound in solids is several TIMES that in air) you get a "pre-echo" radiated from surfaces close to you (like the desk) - similar to early reflections, only even EARLIER Crying or Very sad Few speakers are heavy enough by themselves to work well by placing elastomer pads right under the speakers; this usually causes the m-s-m resonance to be in the audible range. That's why it's better to "spring" the entire speaker "pillar" and hard fasten (straps or something) the speaker cabs to the pillar, so the act as one mass in the m-s-m equation.

Somewhere here there was a design for a speaker pilar that had a shelf and a couple of straps around the speaker to hold it tight to the shelf so that it didn't contact the front wall at all. That was what I was going to do. That brings up a question though: in the m-a-m equation, is the speaker pilar mounted (hard) to the floor or does it sit on something (i.e., rubber, wood) which becomes the -a- part? In thinking back over Sir Paul's speakers, I think he poured a cement column onto his floated floor directly, so I'm missing where the -a- is unless it is the -a- between the pilar and the wall itself. Thanks, and again, good luck!!!! len

Aloha Len,

Somewhere here there was a design for a speaker pilar that had a shelf and a couple of straps around the speaker to hold it tight to the shelf so that it didn't contact the front wall at all. That was what I was going to do.

Was it this one? http://johnlsayers.com/phpBB2/viewtopic.php?t=718 Aloha 8)

Paul has used mostly the Sylomer for mounting floors, etc, and may have also for his speakers; it's very high damping (several times that of neoprene) so works better for all this stuff. However, in order to get m-s-m resonance low the weight needs to be high; if pillars are mounted solid to the floor, then the speaker weight should be increased, possibly by adding a thick steel plate on top. Ideally, your pillars should be in contact only with the earth; then there's more than enough damping that you can just put rubber pads under the speakers, and the pad's only function in that case would be to stop rattles, and keep the speaker from moving around on the pedestal. However this is a HUGE job to get right for a less-than-world-class million-dollar facility with REAL acousticians and engineers doing all the heavy math for location, etc - not too practical for a home/project studio (even though I've not yet ruled it out for my new build :? but probably WILL rule it out before I'm done)... Steve