Step By Step Studio Tuning

Steve... Would using a strap to hold the speaker be secure enough if the speaker is slightly tilted down at an angle? (Newton's Law again!) Or is there another method for securing a "tilted" speaker? (Len sorry if this is not the correct protocol for asking a question in your thread!)

Steve, Now I'm really confused. Is the -a- in m-a-m the material between the speaker and the pilar or between the pilar and the floor/walls of the rest of the studio. I don't have a problem putting a steel plate on top of the speakers if strapping them down doesn't work. Kendale Yes, that was the design I was talking about!! camistan, As far as I'm concerned, it is very much ok to ask your question here. It is relavent to the topic of the thread and therefore, relavent to me too. I can't think of ALL the questions! :-) len

m-a-m is the derivation of the mass-spring-mass equation - air is a spring, in fact a fairly STIFF one; so for walls, we refer to it as m-a-m - in any OTHER resonant system, whatever is being used as the Spring is the "Meat" of the sandwich, so to speak. IF you rest a speaker on a foam or other flexible pad, the speaker mass and the mass of the support are separated by the spring that is the rubber or foam, etc - so this is your m-s-m combination. calculating the resonance of this involves the two masses and the elasticity of the "spring" material. Damping is yet another factor, and the higher the damping the less problems at resonance. There is always more than one way to do things, and most speakers aren't heavy enough by themselves to make a large enough mass to get resonance below audible; so two ways around this are to (1) mount the speaker SOLID to the "pillar", and float the entire pillar/speaker combination - this will lower the resonant frequency a LOT. (2) solid mount the pillar, float the speaker on the pillar thru rubber/elastomer, and add weight to the TOP of the speaker to lower the resonant frequency. I'm off to last night shift, got my ass ran off last nite so had 0 time to work on your CR, sorry; on the previous subject, if it's still confusing say so and I'll try to add more later... STeve

Thanks Steve. I knew the m-a-m equation, I just couldn't find the "meat" as you said. In the design that Kendale linked to a couple of posts back, the speaker was strapped to the stand (which was what I was intending to do) and it appeared to be bolted to the floor too so I couldn't find the -a- in there. So, it sounds like my best option is the "float the pilar/speak" option. Any suggestions on what I could float the pilar on that would give it enough stability not to fall over and yet not couple (through flanking in the floor) to the rest of the room? What about a rubber mat or something like that that is cut big enough to fill the triangle behind the wall? As to what comes after mounting the speakers, I'm going to take your advice. I bought ETF (and the new program they have) and I already have a measurement mic so after I get these speaker walls up, I can start testing as I do each treatment for both placement and effect. len

For support, you'll need to know what the floor's like UNDER your pillar; then figure the total weight of pillar and speaker (including any sand or mortar fill) and rig some sort of test like I showed on the first page of Aaron's big thread to find the size pucks you need (one near each corner) in order to get 10% compression. EPDM is longer lasting than neoprene, Butyl has lots better damping, but with that much weight I'm not sure how much that would matter. I've got more on your drawing incl. dimensions and stuff, just got home from last night shift tho and need to crash. Will get it up sometime tonite... Steve

The floor under where the pilar will go is commercial vinyl tile over a concrete slab. len

Still working on your CR - hope to post sometime Sunday (gotta work extra 12-hour shift, but should be able to do that anyway) - you'll probably need to remove the vinyl where the pillars go, BTW - but don't start til I post new room layout. BTW, CAD isn't translating well to jpegs; which program do you use, and which autocad file formats will it import? Steve

Steve, Thanks for looking at it! I'm really ready to start on it now (all the little projects to fill in are done). As (bad) luck would have it, my step-daughter gave the computer a nasty virus and it's been in the "shop" for the last week and a half getting cleaned up. I believe the formats it can EXPORT are R12, R14, R2000, R2004. Also, I think it can take DWG and DXF although I believe you were only able to use the DWG (or was it the DXF) when I tried to export them to you in the first place. I'm eagerly waiting to see what you've got up your sleeve for this room! People are beginning to line up outside the building already. len

While I'm waiting on the control room monitor mounting details, I've got a quick question: When I started this thread, you mentioned right off the bat that I should put a slat resonator wall in the main room from the edge of the window to the drum room down to the South East corner of the room. Is this still recommended? I'm assuming that this is also floor to ceiling. Just as a thought, could I build a bench seat on the lower part of this (with lift up seats for storage) as long as the slatted area is sealed air tight? Thanks! len

Yup, and yup; the slat is mainly to break up parallels, and tuned to roughly the main irritation factor in a lot of rooms (300 hZ, which is also main modal freq for kick drums) - bench, good idea... Steve Managed to (dumb) leave my laptop in my locker at work over last days off, and it's the only one with your stuff on it - hope to get you going soon, sorry... Steve

I'm replying to this mainly because I stopped getting email notifications of changes (happens from time to time). On this slat wall/bench seat thing, if you can picture the bench coming out from the front of wall at whatever height benches are supposed to be, would I need to extend the "seat" of the bench all the way back to the existing wall or could it be open behind the seat as long as the cavity was air tight? Also, should the entire space behind the slats be one giant cavity or should it be divided up into separate spaces that are 24" OC (the same spacing as the studs in the new wall? Hope you get your laptop back soon! I'm waiting with baited breath (and raised hammer) to get the soffit wall in so I can make some music again! len

The bench should NOT intrude into the cavity behind the slats; it won't make any difference if you mount a bench right to the slats themselves, if they're strong enough; it isn't the slats that "resonate", it's the air column that's contained between the slats and behind them. That's one reason why you need cloth and absorbent right up against the slats inside, because you don't WANT the slats to vibrate if possible - it would color the room sound. You can go either way with internal dividers; using them would actually improve the range of the trap, since you'd be using several separate chambers behind same-spaced slats, each with a different average depth (therefore a different frequency range) - They've been done both ways; if you're planning on that room being your drum room, I'd consider leaving the dividers out and centering the trap for 300 hZ, or you could put dividers in maybe HALF the cavities and leave the other half as one larger trap, and use that portion's AVERAGE depth in calculations for your 300 hZ absorber. I've been working on your CR but find that I need a detail of your front CR window as it is now; exactly how you have (or will) frame your window, mount both glasses, frame the wall (single or double frame, ??) I'm looking at using 1/2" plexiglas extensions to the inside of the speakers, so they will make the baffles large enough without blocking the view, and I need to know where each component of your front wall is and how it's connected to what, etc - a DETAILED drawing or thorough explanation of how that part is done. For your rear trap, what seems to work out is to build a frame across where the little alcove is, making that entire part of the room a "non-environment" trap, and putting the couch just in front of that; this puts the couch in a good location for even modal distribution overall, even though it makes the room smaller. If you're getting antsy, maybe the quickest way would be phone; let me know if you're interested in this, and I can let you know the cost (I give members 50% off) Basically, I just need more detail so I can draw up some workable soffits for you; however we get there is up to you... Steve

Hi Steve! Again, thanks for the reply. Let me see if I can knock down these questions: 1) This is NOT going to be used as a drum booth - at least that is not it's primary purpose. If you look at my first drawing in my [url="http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4488"]build thread[/url], there is an 8' 1" x 11' room just to the NE of the "big room." That WAS going to be my vocal booth until I framed the walls up and saw how big it was! The vocal booth is now carved out of the lower left hand corner (SW) of the big room. I'm assuming from your last couple of posts that a good starting point for the drum room would be a panel resonator or two tuned to 300 Hz for the kick drum. I have two walls and the ceiling that are available for something like this (the other two either have a window or door in them). 2) On the slat wall, you suggested going from the drum/big room window edge to the SE corner of the room. At the corner, the last 3 or 4 feet are going to be very shallow, i.e., possibly not doing much of anything from a resonator stand point (especially if I have dividers on 24" centers). Is that going to provide any useful function beyond splaying that wall so it doesn't reflect off the two other wall sections on the opposite side of the room that are currently parrallel? I'm just wondering if instead of a bench in front of the slat wall, maybe a "Denny's semicircular corner booth" (without the table) might not be better. I'd still get my storage inside and I would think people sitting on it might color the response LESS than if sometimes they are sitting in front of the slat wall and sometimes not (or moving during recording). 3) I AM gettting ansty :-) and I agree that it's probably phone time. Let me know the costs and also if you would have any objection to me recording the conversation since I am horrible at taking notes. I am self employed so I can pretty much work around any time that works for you, day or night (I'm on Central Time in case you hadn't infered that from my location - sometimes it feels like we are so far out in the boonies that we are a few YEARS behind but it's only 2 hours). 4) You kind of lost me on the CR alcove. Are you suggesting that I just cover the whole thing up (perhaps with a solid door and take it out of the picture all together? I had never intended for any one to ever be in that area (although at one time I had considered making that the entrance to the CR itself instead of putting it on the side like it is now). The CR right now is rather large so putting the couch on the back wall (which I think is what you are suggesting) was something I'd always planned on. In case I hadn't mentioned it before, I used the "Blue Bear Studio" CR design as a starting point and my dimensions are pretty close to what's shown for his design when it comes to the control room. In fact the whole studio started off as a modification of that design because the dimensions of his space and the location of the pilars down the center of the space were almost exactly the same as mine. By "design details" of the CR front wall, I'm assuming that what you need are the construction details, i.e., where the studs are, how the window area is framed out, how it's attached to the building (anchored at the floor only), etc. I'm going to assume that this is correct and I'll see if I can get you a measured "as-built" drawing. I've got to drive a church bus this morning so I'll be tied up until noon or so but after that I'll see what I can whip up. If it helps any in the mean time, there are several pictures on the construction thread that show the framing. The only thing that really changed (and now I'm thinking this might have been a bad idea) is that I shrunk the window down 6" on each side to go from 6' wide to 5' wide so that I'd have more room for the soffit wall. The post in the big room (which couldn't be safely moved) really prevented me from seeing any more of the big room than I see now with a smaller (and cheaper) window so it wasn't a great loss. The "problem" is that all I did was frame out a stud on each side (with no stud underneath or above this "little" stud). I am at a point where I COULD remove these and put back the 6' wide window. I think the other thing that should be considered at this point is a "reality check" about the actual use of the room. I am more than likely NOT going to be recording an entire band at once and mixing down to a stereo pair without keeping the individual audio tracks so what I need accoustically for tracking is not the necessarily the same as what I need when I'm doing the final mix (which doesn't need visibility into the rooms. Do you see where I'm going? Could we fashion something that would be pulled out, hinged out, moved in from somewhere else (perhaps the little alcove/storage area) when it comes time to do the final mix? I also have a pair of powered M-Audio BX8s that could be used as near-field monitors on stands right at the mixing console when it comes to final mix time and use the wall mounted Polk monitors when I'm tracking. I use Cubase SX3 so I can record each mic and keep the original audio files which might need adjustment at final mix but I can't see how the anything but the levels would need to be changed. Do you think this idea might work? Let me know what you think and also what the cost/time would be best for you to hammer this out on the phone. Thanks, as always! len

Sorry, things got busy today with non-studio stuff. I'll try and get up the drawing tomorrow mornng. len

I couldn't decide whether to put this in my build thread or here in the tuning thread but decided here. What I've got is 3 "tables", two under the windows between the main room and control room and drum room and main room, and the other against the opposite wall mostly to have a place to put the mic connector panel. (See pics below). The question is what should I cover them with? To give you an idea of size, they are all 3' (more or less) high and the two under the windows are 5' wide, with the one by itself about 28' wide. Should I fill these with insulation (fluffy) and cover with cloth or cover them with a hard (plywood w/ Formica veneer) surface for a little diffusion? The drawbacks to absorbtion are 1) being at floor level, I don't think the cloth cover is going to ask long, and 2) it's at floor level not up on the wall. Any comments are welcome. Len PS: Steve, I'm having to hand draw the CR front wall details but hope to have them done today.

Steve, I can't get a framing drawing out of my software so the following pictures are the best I'm going to be able to do. They show the construction of the control room wall. The only difference between these and the way the walls are now (asside from being covered with drywall and painted) are a couple of 2x4s that I added on each side to narrow down the window to 5' instead of 6'. One one of the pictures, I tried to cut out the parts of the picture that are part of the OTHER wall (the main room wall) that is right behind this one. As to the "tables" that I'm building under the windows, since I didn't hear anything, I've gone ahead and covered them with 1/2" plywood. I am planning on finishing with Formica (or something similar). If this is NOT acceptable (i.e., they should be filled with insulation and covered with cloth instead, PLEASE let me know before I order the Formica. Thanks again. Len

Len, I got your PM; I've been lucky to get 4 hours sleep the last week or so, but plan on working on your CR front tonite. On your table scene, if you've covered those frames all over (not just the tops) with plywood, you've just built undamped, hard-to-calculate panel resonators - with at least one being in the center of a wall, it will try to affect 2nd and 4th harmonics of that wall's axial modes. This might be a good thing, but usually NOT; more likely, they will "suck out" frequencies that may already be a bit weak. Two ways I'd consider - first, fill with insulation and cover with cloth. This will be the LEAST likely to negatively affect room acoustics. Second, if you want the sides of these tables solid I would GLUE heavy rockwool to all the inside plywood surfaces to damp them. They might still act a bit as panel absorbers, but much more broadband due to the damping (therefore less detrimental) Sorry for the delay, I REALLY need a vacation about now and there's not a snowball's chance in Hell it's gonna happen... Steve

I can (will) take the plywood off the sides (I'm still going to need something to lay on the top or are you suggesting that I just remove the tables all together? That IS an option since all of attachments to the walls are into studs and don't penetrate the walls. My main reason for having them there in the first place was to have a nice location for the connectors to attach to (that wouldn't come off as easilly as a little box attached to the wall) and to have storage underneath for cables, mics and such, and a table to put drinks on during tracking. I can see how I've got panel absorbers of unknown frequency and that might not be a good thing. Since they are not supported except around the edges, they vibrate pretty easily. Good luck tonight...I really don't mean to push you, I know you're extremely busy and appreciate ANY time you give us here. len

The tables can stay, even the sides if you need them for connector mounts, although I probably wouldn't; but whatever panels (including the tops) that stay WILL need to have 3 or 4" absorbent glued to the inside for damping; it doesn't even need to be 100% coverage, but the more the better. I'm getting closer to done on your CR, but need more info; couldn't find anywhere which Polks you're using. mainly just need to know whether they are dual woofer (MTM) or single at this time. Here's a (really) rough jpeg to date, still working on framing and need to do a front view showing bezel, etc - the jpeg is to scale, but not labeled/dimensioned. I only need 36 more usable hours in a day and I'll be set... :wink: Steve

knightfly wrote:

couldn't find anywhere which Polks you're using. mainly just need to know whether they are dual woofer (MTM) or single at this time.

Well, kind of both. There is a woofer (in the middle, tweeter on top) and a "bass resonator" or something like that which looks to me like a speaker from the front but no coil/magnet on the back. There is a center "plug" on this that appears relatively heavy (I think it's wood) which I think gives it a little resistance to motion. As I understand it, this vibrates based on the air that is compressed/expanded inside the case (I guess kind of like a pressure relief valve). There are no ports in the front or back and they are passive not active so heat isn't an issue. And if it matters, remember that I have a pair of M-Audio BX8s that I could use instead (except that these are rear ported and M-Audio's engineer recommended NOT soffit mounting for heat/performance reasons. The design so far looks GREAT. I know you're not done yet but on the fold out baffles for mixing, how stiff would these have to be? As solid as if it were part of the wall or just not flapping when the A/C comes on and off? Just out of curiousity (sp?), it the purpose of raising the couch just to get the ears of people sitting on higher or does it serve some other purpose? len

The "non" speakers are passive radiators; they're supposed to act similar to a reflex port but without the audible "chuffing" that sometimes accompanies ports when speakers are pushed. The baffle extensions could be either triangular shaped inserts that would stand up in the corner during mix, or another way would be to use 1/2" plexi extensions across half the CR window from each side, screwed in place permanently. Too floppy and they may cause more problems than they solve. Head height is the reason for the dais under the couch, for two purposes - one is getting listener's heads out of the nulls, which wouldn't require the dais at all because they're ALREADY below center by about the right amount; but it looks to me like your CR window is kinda high, so if sitting on the couch at floor level doesn't give good line of sight into the live room, you'd need to raise the couch ABOVE the null point; this would take about 15" of rise so heads would be about 8" ABOVE the 2-4 null point instead of 8" BELOW it. You would also need to damp the decks of those two levels or you'd have MORE panel resonators mucking things up; by all means, if there's good line of site WITHOUT the riser then you shouldn't do it. I'm gonna try to PM you a zip file (R14 DXF) of what I have so far; jpg just doesn't cut it. Let me know if it's readable by your proggie... Steve

Dumb PM system has me limited on attachments; here's your answers/sketch - What was the reason for the gentle curve? Is it for noise or better air flow? Both; better air flow = less noise, especially near the register. Now to the question (sorry for the long lead in). What is the problem with just making a box out of duct board with a hole in the top and a hole in the front and sealing all of this from the rest of the cavity behind the new wall? If it\'s noise, the duct board and flex duct up to that point should take care of it. If it\'s poor air flow (making a short 90 degree turn) then I\'ll have a little bigger problem. A smooth curve would be best, so there\'s minimal turbulence near the end of the run where it WON\'T get masked by the flex or ductboard - I\'ll sketch one option that should help. On a somewhat related issue, should the corner of the \"hanger room\" have insulation across the corner or is just covering all the wall surfaces with 4\"/4lb MW good enough? This is intended to be a \"black hole\" - when in doubt, cover it with MW. Also, what should I do with the floor and ceiling behind this wall? Should I mount MW on the floor and ceiling of this cavity too? Same answer - although it\'ll be easier if you get your hangers done BEFORE doing the floor; they tend to be heavy, and being able to get directly under them to lift will make it easier. I\'d start at one end of the trap, and work my way to the other end with the hangers. Step 0 - set your speakers up at the front of the room and listen to a couple of your favorite CD\'s, make mental notes about the sound quality - set levels to 85 dB(c), slow response, at listening position. Mark listening position/speaker positions for repeatability. Then, walk around the room and take note of changes in sound; peaks, nulls, etc... - you can even take the meter with you and note actual level changes just for fun. Step 1 - ceiling. Step 2 - walls (this will help hold the ceiling MW in place- a couple beads of construction adhesive will hold the stuff til side walls are in place. If necessary, find (or make) some Impaling Clips for the inner walls of the trap to support the MW - a simple way to do this (if you have solid place to nail) is to drive some 16d nails into rear wall, leaving all but about 3/4\" sticking out; clip the heads off and force the MW down over the nails. I\'ll include that in the sketch. Step 3 - hangers (\'way before this, the hanger support frame should be done) Step 4 - MW on floor. Step 5 - MW in stud cavities across the front of trap. Step 6 - cloth (got fire retardant spray?) And the sketch... Steve

That's kind of what I was hoping you meant. :-) When you said "gently curving", I was thinking curve instead of 45 degrees. It appears that you've got a drywall "box" around this though. Is this correct? I have enough DW scraps left over to do this (although I was really hoping I'd seen the last of drywall dust!!! :-( ) On the front wall, I know you've been busy helping others but I had a thought about this. Could I just extend the speaker walls straight up to about 1 foot from the ceiling and then building "around" the vents (just like the rear wall drawing above but without the "soffit?" I'm going to have a ceiling cloud that will obscure the vents (visibly at least) so no one would see this. If that's not clear, I'll try and work up a drawing. BTW, on Saturday, I just stacked up my cinder blocks in the "right" place, put my monitors on top of them and hooked up my power amp to a CD player. I had already stacked all of my MW along the back wall (just to have a place to put it for now). I cranked up the sound and it was AMAZING. I heard things in CDs that I never knew were there. I could close my eyes and "see" where each instrument/singer was. This was with no ceiling cloud, no side wall absorbers, nothing behind the speakers but the bare walls. I can't imagine how much better this is going to sound once I've got the insulation packs open and finish the treatments! Since I'm going to be building my own mixing desk, does anyone have any thoughts on the height I should make it? I'm just a tad short of 6' tall and I'd like to have a 19" rack unit on each side of the desk (maybe 12 to 14 RU each) and it would be nice to have at least one rack on "top" so I can put in my patch bays and not have to get on the floor to patch things. I'm thinking the table top should be somewhere around 27 or 28" off the floor. Does this sound right? Thanks!!! len

Aloha Len,

BTW, on Saturday, I just stacked up my cinder blocks in the "right" place, put my monitors on top of them and hooked up my power amp to a CD player. I had already stacked all of my MW along the back wall (just to have a place to put it for now). I cranked up the sound and it was AMAZING. I heard things in CDs that I never knew were there. I could close my eyes and "see" where each instrument/singer was. This was with no ceiling cloud, no side wall absorbers, nothing behind the speakers but the bare walls. I can't imagine how much better this is going to sound once I've got the insulation packs open and finish the treatments!

Sweet! Any pics for us? :wink:

Since I'm going to be building my own mixing desk, does anyone have any thoughts on the height I should make it? I'm just a tad short of 6' tall and I'd like to have a 19" rack unit on each side of the desk (maybe 12 to 14 RU each) and it would be nice to have at least one rack on "top" so I can put in my patch bays and not have to get on the floor to patch things. I'm thinking the table top should be somewhere around 27 or 28" off the floor. Does this sound right?

I'm using Argosy's console for a Soundcraft Ghost. Top of armrest is 30 1/2", top of rear shelf is 37 1/2". If I were to put a rack unit under the armrest area, there is 25" clearance. Hope this helps, Aloha 8)

Howdy, Kendale!

Kendale wrote:

Sweet! Any pics for us? Wink

But of course! However, since it's more building related at this point, I've put them in my my studio build diary. Enjoy!