5.1 Postproduction in Garage

Steve, Sorry about the delay, had some mixes that had to get done. I've got a call in to the engineer but have not heard back. I'll let you know what he comes up with. None of the interior walls are load bearing as you stated. Thanks, Dave

Hello Steve, maybe this will help explain why the sag is important, and the external holddowns are jeaprodized. http://www.tradac.org.au/tradac/atd/arc ... russes.pdf fitZ :)

Steve here's a pic. The south wall is on the left. From the south wall we put in the new joists "24 on center. The original structure actually started about '1 away form the south wall so the spacing between the new and old isn't equal at all points. The engineer I worked with before is so busy he hasn't had time to take a look. So the big question is will it support 2 layers of 5/8's the 20 gauge stud then another layer of 5/8's off of RC? I don't think anyone would want that coming down on them :shock: We will make room for deflection. "I'm still confused as to wanting to connedt the wall frame to "rafters", instead of the horizontal "joists" " My fault I meant joists. By the time this is over I'll actually know what I'm talking about. Rod any thoughts? Thanks, Dave

Steve sounds like your busy. Rod any thoughts? Thanks, Dave

Sorry Dave, musta missed your earlier post - I know what I'd REALLY like to recommend, but I'm not sure all that roof would fit comfortably in the particular orifice of the person who built it... Seriously, If you can't literally remove all that roof framing and start from scratch, what you WILL need to do is to COMPLETELY duplicate the trusses that are currently on 4 foot centers - right now, you have rafters (only) on 2 foot centers, with every second rafter made into a "W" truss - in order to gain enough strength in your ceiling frame to support the double leaf system I suggested earlier, ALL of your ceiling joists would need to be part of a truss. You already have the rafters in place, but your new joists would need to line up with those rafters and have "W" bracing installed the same as your original trusses. You need each joist supported by truss construction. Once that's done, THEN you can hang sheet rock; I would NOT put more than two layers on each side of your studs at most. Also, you'll need to use long enough screws when fastening the studs through the upper layers of sheet rock so that you get a MINIMUM of 1" penetration into the joist itself. In your last pics, I see a knot on the bottom edge of one of the joists - this is NOT good; knots should be placed in compression, NOT tension - this means they need to be on the TOP edge of the framing member instead of the bottom. If that knot is close to the end of the board it's less of a problem, but still shaky. If, when you add the "W" braces to create trusses, those braces fasten to the joist near the knot, it can be left as is... If that roof stayed in place with 4 feet of snow on it, I guess adding double the trusses would allow you enough strength for additinal mass - but you're right, I think we need Rod to look at this if he gets a chance... Steve

Steve, Thanks for the reply. Unless I misunderstood the engineer's original instructions he did not want the new ceiling joist tied into the rafters that aren't trusses yet because he wanted the load transferred to the walls. Make any sense? It's also possible he didn't understand the amount of mass I'm trying to hang. He is busy with building some little mall I can't imagine why he doesn't have time for little oh me. Anyway he's trying to find time to stop by and take a look. I would like to hear Rod's thoughts also. Bottom line is, it's crap right now and it needs to be safe. If you need any other dimensions or pics let me know. Good news is we are getting alot of other stuff done in the meantime. Again thanks for the patience and advice. Dave

My span tables don't cover wierd construction, but for 2x8's on 24" centers, douglas fir #2 and better with a 20/10 load (you don't want to go lighter) I'm showing a maximum span of 13'6" - isn't your span closer to 20 feet? Anyway, that's the criteria I based my comments on - I built trusses in place in my barn when removing two of the inner poles for a clear span - I had only built them on one side of each set of poles before removing the poles, after which I had intended to double them for the other side (12 foot centers, 2x6 purlins over 2x12's) - before I got the chance, we had one of our infamous "mini-hurricanes" of around 80 mph winds, and nothing blew away - had I relied on brute force with just those single 2x12's on 12 foot centers, I'd have been building a new barn roof at minimum. If your engineer ever finds the time, I'd like to know his reasoning for this not being necessary... Steve

Steve, I'm with you, it doesn't seem right. Glad I ran this by you it confirms my uneasiness. Unless I get word soon it will get built as you suggest. Thanks, Dave

Steve, Actually had some time to research a bit. Found a span calculator that came up with your exact number on the span. Just trying to figure out what I'm talking about :shock: There had to be a communication breakdown between myself and the structural engineer. Not only can I get 4 feet of snow, winds can reach 70mph so this roof has gotta be right. Again, Rod any input? Guys, each day I value this board more and more. Thanks, Dave

Steve, I'm back, been working on the room pretty steadily over the last 3 months. The rafters went in just as you said after the engineer came back and took a look. Drywall is finished and painting has begun, hoping to post pics soon. Acoustic treatment is being considered and I would like to ask your opinion on bass trap and broadband absorber size and placement in the control room. Also, clouds, how many sq/ft in the mix area 2 or 3 inch 703? These are some of your thoughts in the beginning.

For my future surround/stereo control room I'm considering building "sockets" into the front/side walls so I can make "inserts" that are either absorptive, reflective, or diffusive so I can see for myself whether the new "ESS" , or Early Sound Scattering, concepts are valid. If you're not interested in ESS, then you could build reversible inserts with paneling on one side and cloth covered fiberglas on the other. From what I've seen so far, most 5.1 mixers are keeping the control room absorbed wherever a speaker is aimed, and replacing ambience with DSP. Once you put surround speakers in, the RFZ approach gets screwed. Broadband absorber - frame, thick fiberglas board, cover. Space from wall for lower frequencies. Leave room for as many bass traps as you can, panels take less space but absorptive ones are more broadband. You need to watch for even absorption across the frequency band to keep reverb sounding natural. Ceiling/wall corners are good places for traps, they don't take up valuable floor space and corners are where they work.

Thanks, Dave

Dave, long time no hear - glad your engineer re-looked at the place, sounds like he made the right assessment (after all, he agreed with ME :? ) Here's your drawing for those without Word on their machines, sorry I'm needing to bail for now - I'll get back to you probably late tonight... Steve

giles117 wrote:

Density of the material. OSB is different. I prefer and have been recommended particle board for the past 6 years. who knows, maybe my sources were mistaken, maybe it doesn't matter. I just stick to what I have found works well. OSB might work just fine. I can't speak on it because i have never used it. That is why I said "I would use" Unless someone gives me convincing evidence of the similarity between the products, I will stay with what works best for me. This is the 4th floor I have floated and I have learned from the mistakes I made hence my reason for stating what I have stated. (Not irritated just being frank Carl.) While typing this post I did tons of research and I have been unable to find any information regarding the Density of the flooring material. If someone can find it let me know but for now I will keep using Particle board. Dtess mentioned 1-1/8" OSB. In looking at his design he is showing one layer. But that is not recommened. 2 flooring layers is recommended. P.board is rated at 45lbs / cubic foot Steve may have information I have not read so I will leave that open for argument. Not too mention Particle board costs $8.00 a sheet here in Michigan. :) Bryan Giles

If you talk to a good wood floor contractor, you will find that the US guys do not recommend it as a subfloor. Floors may have moisture, and the sandwhich does not hold up over time. You should never fasten wood flooring to it directly either.

Steve, FYI the door into the house is out. There are 2 doors with a air gap between them from the control room to vocal booth. Also 2 doors with air gap, between vocal booth and drum room. A window has been added between the vocal booth and control room. Yeah those are the only changes since I started :lol: Dave

Dave, sounds like a better idea overall on the changes - brent, what is "it"? OSB, particle board, ??!? Steve

Anybody have any thoughts on bass trap type, size and location? The corner behind the mix position will have a trap but not really sure how big to make it. I was thinking broadband absorbers on each side of the window and clouds over the mix position? Clouds in the drum room with a bass trap/broadband absorber. On the wall, some hinged units that can open with absorbtive material. Thoughts from the forum with smaller drum rooms and treatment? By the way floor was done with 2 layers of 3/4 ply and it worked out great. Thanks, Dave

Dave, still short for time but I'll see what I can do, sorry for the wait - First, if you'll be doing surround your surround speakers will be almost too close and still stay on your circle - one would go right next to the door hinge (top center of dwg) and the other opposite, to be around 110 degrees - 120 would put them into the wall from the look of it. Another option might be a quality stereo delay so they could be a bit closer to you and still be same arrival time as the fronts. This would need to be sub-millisecond adjustable, I've not done research on what's available yet. Reason for those comments has to do with the rear trap - it should be as deep as you possibly can make it, and "Newell-ized" - what I would term "progressive impedance", or in other words softer stuff near the face graduating to heavier absorbents (up to maybe 8 pcf) with hangers at the innermost part - I'll try to scale your room for CAD so I can draw an example, but this may take about a week or so the way things are at present. Another reason for max depth is the increased width that makes - 90 degree corners fire whatever comes in right back out as a parallel return, so you do NOT want that rear corner empty. Ceiling/wall corners are also fair game for traps, but you may want to wait til you see what the room sounds like - it's next to impossible to calculate these things so ETF after the basics would make more sense; then you could design whatever additional treatment is necessary once you know what the room's doing... Steve

Steve, Again, thank you and the forum for all the help and knowledge. If I recall correctly the circle is a 7ft. diameter. I know the surround placement isn't ideal. The plan is to put them on stands and move them out of the way when they are not in use. I'm going to position the surrounds and listen to see which placement will work better 110 or 120 degrees and as you suggest start treating the room as necessary. Yeah that corner looks like trouble. The thought was to build a big corner trap but thought it would be best seek some advice before diving in. Glad I did! Thanks, Dave

knightfly wrote:

Dave, sounds like a better idea overall on the changes - brent, what is "it"? OSB, particle board, ??!? Steve

Sorry. OSB is strand board, chip board, etc. People in this neck of the woods use it as a plywood alternative when they can. Particle board...I should have said MDF. Same thing really, but MDF has the smooth laminate finish on both sides, particle board does not.