Walls-Walls & More Walls

what's up Steve, I took a look at Aaron's 3-D plans and made an outline of my studio with it. I don't know if I got this right but here it goes. On Aaron's first 3-D plan he has double sheetrock for the inner wall and goes on from there with a enough space to soffit and build he's bass traps for he's splayed walls is this correct? I'm thinking it's something like John's "inside out" wall design where I use the the inner leaf as an "inside out" wall but instead of finishing with a cloth finish like you explained to me before for example I soffit my monitors and build my bass traps and then finishing it off with some kind of material(like sheetrock ? ) for my splayed walls. or do I just leave the inner wall open in other words no sheetrock where I have the yellow lines pointing to in the second 3-D drawing? Thank You Ozzie

Ozzie, nice weather and tons to do, so I'll have to catch this tonite when I'm too tired to do anything but type... Steve

:shock: Holy crap....is that TWO sets of TWO LEAF systems....One for the outer shell, and one for the inner shells..man I AM confused now....so the BLUE lines are TWO leafs of the outer shell...is that correct? And the orange lines are TWO leafs of the room within the outer shell.....? Where have I been....wait, this can't be right. I MUST be having a bad dream. PLEASE clarify this Steve, cause if that is correct......goodbye STC dreams. :P AND I've been in a haze.... :cry: fitZ

Hey Rick, UTMAIA as usual, but bottom line - I've been pounding the 2-leaf thing into people's heads all this time mainly so they stop asking "what if I build a 6" block wall, then move in 2 feet and build a 4" gypsum wall, then move in another 18" and build a cardboard wall with saran wrap covering only one side, etc, WHAT IS MY STC? " The reality is that yes, 2-leaf is the most efficient use of materials. The second reality is, that adding more leaves will not LOWER the STC of an existing wall, but it's NOT the most EFFICIENT use of materials. However, there are times when there is no choice (sound locks, splayed shells within buildings, etc) I'm still working on a quorum on this among a few trusted authorities, and when I'm ready I'll update my comments, complete with graphics, on this forum. Til then, f--- off, I'm busy :evil: :evil: (That's me, beside myself -and no, that wasn't the REAL "f--- off", just a joke) Trust me, this WILL get cleared up within a few days... Steve

I reposted my drawing because it seem to be making people confuse, it' a two leaf system with the blue line as the outer wall and the orange line as the inner wall but I am using the inner wall as a "inside out" wall and the green walls with space behind it is where I soffit my monitors and build my bass traps but I don't know if this is right because I'm just going off Aaron's 3-D plan. I'll repost my question again: What's up Steve, I took a look at Aaron's 3-D plans and made an outline of my studio with it. I don't know if I got this right but here it goes. On Aaron's first 3-D plan he has double sheetrock for the inner wall and goes on from there with a enough space to soffit and build he's bass traps for he's splayed walls is this correct? I'm thinking it's something like John's "inside out" wall design where I use the the inner leaf as an "inside out" wall but instead of finishing with a cloth finish like you explained to me before for example I soffit my monitors and build my bass traps and then finishing it off with some kind of material(like sheetrock ? ) for my splayed walls. or do I just leave the inner wall open in other words no sheetrock where I have the yellow lines pointing to in the second 3-D drawing? Thank You Ozzie

Hello... OK, it appears the drawing of my control room is stirring some controversy. Let me explain it some... The Blue line that Ozzie has on the outer wall, is the existing foundation of the house. Concrete Block. The Orange lines he has drawn, is the "outer shell" so to speak of the control room. This is new construction. Only one side of this has drywall. The inner splayed walls, I haven't a clue yet what to use for these. I'm going to assume that the front walls where soffits will be, is going to have MDF in parts or all of it? The splayed wall on the left side of the control room, I don't know if this needs to be drywalled, insulated and covered w/ a peg board, or just insulated and covered w/ cloth. I'm not sure how to allow the low frequencies into that corner for use as a bass trap.???? I'm not counting the inner splayed walls as a leaf, as it's being used more to tune the room. What I am considering as a leaf, is the outter wall around the control room, and then the wall running parallel to the wall on the right of the control room (between CR and tracking room) this is the double wall theory...mass space mass... Same thing between the back of the control room and the iso room...mass space mass in the double wall construction. Part of the reason why this is set up the way it is...When I bought this house this last year...it has a moisture problem. It was a fully finished basement, but...4 days living in the house, I put my hand on the wall...and well, I went right through it. And although I rerouted the drainage of the gutters away from the house, and spent a fortune on using drylock, etc to keep the water out...I'm seeing it start to come through already in a few spots, (and no thanks to the nearby blasting causing cracks) and so this is why everything (the walls & floor) is completely away from the foundation of the house. I wanted enough room so the room can breath w/ a dehumidifier running in another area that will pull that moisture out, and not rot my new construction. There are some additional pix on the same thread as to the construction of the walls. If need be, I'll repost them here w/ some modifications. Also, the 3D picture isn't completely finished. I still haven't angled the front walls for soffits. I will be working on the drawing hopefully this week and improving it some. With any luck, I'll be starting the framing on the CR this weekend. I hope this clears some of the questions regarding the design. And I may be wrong on some of what I mentioned about the splayed walls. Maybe Steve can clarify this a little better about the design?? Thanks, Aaron

Aaronw, did you get the stamp of approval from Steve yet on your design because I wanna know if this right so I can start moving on to a diffrent subject. If you did get the stamp of approval can you help me out? Steve- I know your very busy but can you hit me back with some info on Aaronw design because I was so close to finaly understand this wall and soffit thing? Thank You Ozzie P.S. Steve can you take a look at my last picture and question when you have the time.

Hey Ozzie, I can't remember if Steve or John gave the stamp or not. I know in the design forum, I was really close to this design, and they made some suggestions (splayed wall layout). This particular layout is based around the recommendations for doing 5.1. Although I'm probably still another year or two from having the ability to do 5.1 (all my money is tied up in construction), I decided to plan ahead for it, knowing I was intending to go that direction. So I've got all the conduit chases, etc. already there under the floor. What can I help you out with? Aaron

Hello Aaron, say, I'm no expert on this surround stuff, but you should read this. If anything its interesting, and actually has some REALLY enlightening information regarding surround. http://world.std.com/~griesngr/paris.pdf fitZ

Guys, Aaron is on target with his ideas for what is a "leaf", etc - Since there are already two leaves up, I wouldn't even worry about hermetic sealing on the splayed walls; they (with the exception of the front soffits) could be just a light 1/2" gypsum with the insulation set up to dampen the panels, and it should lessen the need for as much bass trapping. The soffits themselves need to be as stiff as you can make them, as I've mentioned before. 1-1/8" ply over 2x6's is NOT overkill for speaker flush mounts, you do NOT want them trying to become passive woofers. Ozzie, what else do you need? I'm probably gonna be close to this busy for the next several months, but I'll try to keep up as much as I can. Last time I tried to catch up with Aaron, he had about 125 questions for me - gotta check in to see how that's going, then back outside while the good weather lasts... Steve

Hey Steve, Yeah, just a few questions on the other thread... :? Who usually carries the 1 1/8" ply? Do the lumber yards usually carry this? Or is this more of a custom order issue? Let me ask this, should I use the thick ply or would it be just as good if not better to use MDF? Looking at your comment, are you suggesting to use Wood 2x6's for the front soffit wall, or will 2x4's be sufficient? Or are steel studs OK? In building the soffit wall, I'm intending on using 2 layers of 5/8" for the outer wall. Should I add / line the inside walls of the soffit section w/ the 1 1/8" ply or 3/4" MDF? I post a diagram of what I mean. Thanks, Aaron

The 1-1/8" ply is standard flooring material, available in tongue and groove - runs about $30-$35 a sheet last I checked. You want those soffits as solid as you can make them, to lower resonance and eliminate flex. 8" concrete wouldn't be excessive here, if you had the money. I'd stay with wood 2x6 for those frames, for just that reason. The rest of the splayed walls can be light steel/gypsum for the added panel trap effect. I'll need your diagram on the soffit question... Steve

Here you go...

No need to line the cavities - your speakers are already in boxes, right? You could, however, use some of that mdf LAMINATED (yes, this once I AM suggesting glueing panels together) to the 1-1/8 ply for a SOLID flush mount. 2x6's for the soffit frames. Are you using Barefoot's soffit plan? What angle are you planning for your speaker baffles? And, are you planning one for the center channel? Steve

I probably will use barefoots design. I need to research it more. Angle...Don't know. I guess I need to figure out where I'm sitting, and the distance. Still haven't been able to figure out the Ray Trace thing in autocad. Don't know how to use the Ortho function. Center channel...Yes. Need to angle the rear soffits too... Glueing the MDF...are you talking about glueing mdf on top of the ply? Double layered wall/soffit wall?

Don't know how to use the Ortho function.

Hello Aaron. The ortho function simply allows you to pull perfect x,y lines(90 degrees). Toggle F8, for ortho off/on while in a line command. Then you will see. The @ prefix is your best friend. fitZ

I know how to turn it on/off. But how do I use it for ray tracing, etc. We're working here w/ everything but 90 deg. angles.

Cadesigner... You say the @ is my best friend. I don't suppose you can enlighten me on this some? I think I figured out some of the ortho (actually I thing polar), but hadn't used cad much lately. Steve, So your suggestion is to not only have 1 1/8" ply, but also laminate another layer (3/4" I assume), of MDF to the outside of the ply? As far as the angles, I have the "horizontal" angle (if sitting at console 60 degrees...which means 30 degrees when building the wall). Not sure about where to start angling the vertical. Should I start from the bottom and angle out, or should I start at 5 foot up and begin my angle? (read that on barefoots forum somewhere). Thanks, Aaron

Bump... Didn't get any reply's so I'm bumping it back up. Of course that was about the same time the site changed to the new server. Thanks. Aaron

Hello Aaron, sorry I didn't get back to you sooner. The bbs doesn't notify me when someone posts on a thread that I've replied to. Ok, in regards to the @ sign. Do you use Autocad? I didn't mean to sound like a smartass, although when I reread my post, it DID sound that way. What a jerk. Excuse me. Alright, for starters, I don't know how much you know about Autocad, but here is what I was talking about. When drawing, there are various ways that you can draw lines. One is using the @ sign. When you enter "line" or L or pick a line button, Autocad promps you to tell it where you are "starting" from. This can be done by either co-ordinates, Osnaps, or just pick a point with the curser. Then the program asks where the next POINT is. Or the end of the line. Again, you can just pick a point as you drag the line, or pick various ending points with the Osanps, such as an intersection, a midpoint or endpoint, or perpendicular etc to an existing line. OR, you can say @(at) so many inches, say 120,(and now direction in degrees) <90(the <sign is an angle command) so here is what it would look like at the command promp. Hit L for line, "enter" ("line" comes up on the command prompt -"select starting point" (which translates as "from" ) Pick a point where you want the line to start from. At that time, the command line promps you for an "end point". Well, where do you want the line to go? That is the key. Say you wanted a line 85" long at 30 degrees......Your command would look like this. @85<30.....and thats it. Or say you wanted it at 60" at 0 degrees. It would look like this. @60<0 Does that make sense. The @ simply means "from the last point" so you don't have to punch in absolute co-ordinates. It is really difficult to illustrate CAD functions on a forum such as this, but there are TONS of CAD forums to help you. Good luck and hope that helps a little. fitZ

Hey Fitz, what we need for this particular "experiment in pain" is a way to reset the ortho parameter from the normal 0 degrees to an angle that's the same as a selected line - in my old tired Dos Generic Cadd 6.1, I can type "OA", as in "Ortho Angle", then hit the = key, the program asks "like what", and I can just click on a line - when I do that, that line's angle becomes the NEW Ortho angle, with all new lines defaulting to that angle or one 90 degrees from it, making it very easy to draw perpendicular lines from the NEW reference surface without guesswork. Somewhere there's a thread where I described how to do a poor man's Ray Trace to figure out RFZ angles, think it's in the Design forum - in that, I explained how I do it. What Aaron needs is a way to duplicate those changes in Autocad, if possible. Go here - http://www.johnlsayers.com/phpBB2/viewt ... c&start=60 and check my post of Jan 24 for an explanation of what we're trying to do... Steve

Hi guys, well, that thread was very entertaining :D Especially your explaination, which btw, is WAY beyond me. I did post a response to Michaels thread at HR along the lines of this thread, that my initial thought to baffle extentions for rear surrounds, is that they are directly aimed back at your head, so early reflections had a perfect "mirror". As to ray tracing, I haven't a clue to what that is. Although I've heard the term, and seen drawings of audio room analysis, using "ray tracing", it baffled me, as my interpretation of a sound wave is that it moves from a source as a hemispherical wavefront, and reflections are generated as new boundarys are encountered, also as hemispherical wavefronts, so the idea of a "ray" eludes me. But I've come to the point in my "quest" that I'm already so far behind current knowledge, that it makes no sense for me continue to "catch up", just to build my little studio. As for changing the angle of the ortho function, never thought about it. I simply copy any line at any angle from any point to any point. Remember, I do simple CAD drawings, nothing in 3D, and although some of the stuff I've had to do was rather complex, I use very few commands to do it. My use of CAD doesn't require the more sophisticated capabilitys of the program. Although I constantly dabble with it, my daily work doesn't require it. I am pretty much self taught, and the depth of the program would take a lifetime to utilize, unless your doing rocket science, and have the time or money to take a course in it. I do not. Nor am I interested in exploiting the depth of it. Current time constraints, wish lists, "honey do's". and light at the end of the tunnel realizations, have forced me to adjust my use of time, to achieve reality instead of pipedreams. There are other commands that I use all the time to achieve results that perhaps better informed users do with commands I'm not familiar with. One of them is the "mirror" command. You can mirror at any angle, and from any point to any point. Also the "align" command is very powerful. You can align an intity such as a line or groups, or blocks, to any other intity, at any angle you so desire. Explaining it here would be frustrating. A simple live demonstration took only seconds for me to see how it works, but I would suggest looking at the extensive help(F1) resource and typing in "align". I should explain it far easier than I can. BTW, if that plan drawing of a control room was an example of your understanding of CAD, then you have as much command of the program as I do, so I don't think this is very difficult to figure out how to do. Any line drawn at any angle can simply be copied from an endpoint to any point you want that line to start from. Then either extend it and trim it as required, or grab the end "grip" point and drag it to where you want it. Another way to extend a line, without changing its angle, is scale. A line is a vector, and scaling it will not change its plotting linestrength. It will however, change its length. Scale it from a midpoint(Osnaps)and it will extend both directions along its vector, to what ever length is desired. Then trim. I personally don't see a need for the angle of ortho being set for multiple parallel line creation, as you can draw multiple lines at 0 or 90 degrees and rotate them. And there are a multitude of other ways to draw lines at the same angle. But for one or two, or an array, or even multiple lines in parallel at even seperations, copying is the way to do it. However, there is an another simple command I use all the time. OFFSET. This command is simply a COPY command, whereby you automatic set the distance to which the intity is being copied TO, parallel with the original, even at an angle. Type in OFFSET, and it promps you for the distance to offset, which you type in whatever units you are using to dimension. One unit will equal what ever measuring system you have set in the dimension parameter settings. Either inches or Metric. Or even miles if your drawing that large. Ha! Autocad has 14 decimal places so you can draw in microns if need be. Same with offset. Well, hope this helps. I am definetly no CAD teacher, but experience often illustrates a different way of looking at things. Like my Dad. Hes a mechanic. A mechanic who never had any money. He learned to do things by necessity. Like crossing the desert in a Model T. When a main bearing fried, they simply lifted the car on its side, pulled the pan, removed the bearing cap, then made another temporary bearing from his leather belt. Beats death. He was 11 yrs old. And when I needed a new alternator but could not afford one, and because the diodes were fried, he simply took the rear part of another type, with the diodes in it, and bolted it to the firewall, and ran wires to and from as required. Getting from point A to point B is all that matters when you have no other choice. This doesn't mean that ortho can't be changed. I just never needed to. fitZ :D

Cool, rick, sounds like we're in similar boats on the cad self-ed... AS to ray tracing, you're right for lower frequencies - below about 300 hZ the wave thing seems to be the model, above that you can (sort of) consider sound to act as light (or a pool ball) and use simple geometry to figure out what will go in which direction - Fortunately, reflections reduce in level fairly quickly with distance, so this laborious method doesn't have to be traced further than maybe the second thing that reflects - main thing is getting the level of the reflections several dB below that of the direct sound (forget how many dB, if I find it again I'll re-post) Glad you brought up the Mirror command, that may be a simpler way that what I was doing for my "polish ray trace" scenario, thanks... Steve

main thing is getting the level of the reflections several dB below that of the direct sound (forget how many dB, if I find it again I'll re-post)

The spec in AES.EBU.the tonmeister SSF and ITU is that reflections in the first 15 milliseconds be at least 10 dB down. Is that the one you are thinking of?

Yeah, thanks - no wonder it's hard to remember, such an oddball # - most everything else is even increments of 3 dB, or 20 dB ... Steve