Floating floor over basement concrete. (Artifact Recording)

Steve, Before I place this second layer on...Should I consider any options of anything between the 2 layers of 3/4" T & G OSB? I'm limited now on floor-ceiling space. Thanks, Aaron

Got another Q on equipment racks. I'm custom building my own. It will be 4 bays wide. 1. I know the equipment is 19". How much extra should I allow for the rails/gear. Should I space it at 19 1/8", or 19 1/4"? 2. What height is the average equipment rack? 3. How many degree of angle is suggested for the front of the rack? 4. How many rack spaces? I'll be adding the rail. 5. What type of wood? Oak, Maple, Mohagany, Cherry, etc...? I've been searching around the site, and found the one on the SAE site, but nothing has measurements. Thanks, Aaron

Somewhat in order - a layer of 1/2" sheet rock between OSB layers would help quite a bit in several ways, if you can afford the extra 1/2". On racks: (1) I would NEVER build racks without having the rails in hand - that way you can set up your centers so that your average rack mount gear has its holes centered on the holes in the rail. You can always put a "beauty strip" over the edge after. Also, if you're doing a full star ground wiring plan I would either use hardwood and build your own "rails" so you can leave 1/8" spaces between units so their chassis don't touch each other, or get some of those little folding isolators and plan on leaving one space open every so often to make up for the isolators' thickness. I've yet to see rack rails that are drilled correctly for using chassis isolators, and since rack gear isn't always single space I'm not even sure you could do that. What your goal should be is NOT having any chassis contact with ground or each other, except intentionally. That way you maintain the star concept of only one ground connection and no loops. (2) The average rack in a CR should be low enough NOT to cause any early reflections back to your ears, nor interfere with the sight lines. Generally 36" maximum, 32" might be better. You would need to ray trace your side elevation to be sure, looking for possible reflection paths. (3) Usually 15 degrees works out good - I'm doing a desk design with the sides set up as slope racks that tilt out for wiring/access, and they will be 15 degrees when closed. This means either short depth units on bottom or a taller "kick panel", but vertical racks are difficult to see everything well when they are shorter than 5-6 feet... (4) As many as you have room for. If you use 32" for height, subtract at least an inch for the top, 2" for the rail over the rack area, and 6" total for toe relief and bottom rail, then figure in the slope, you're left with just over 23" for rails. That leaves 13 spaces, if you're not superstitious :? If you use hardwood rails so you can space between units without chassis contact, you might be down to 12 spaces per bay. If that's not enough, you could raise the top but I wouldn't go beyond 36" total height. That would add 2 more spaces per bay. (5) This is a matter of personal taste, except that if you do wooden rack rails I'd go with either oak or ash for durability. Since this won't show, you could use zebra wood with padauk stiles, or koa/maple, whatever works for your aesthetic. I've also NOT seen any measurements - when I get the time/need, I'll be doing my own from scratch... Steve

What your goal should be is NOT having any chassis contact with ground or each other, except intentionally.

Out of curiosity, and I know I've read it somewhere...either on this forum or another (Maybe SAE or something?), but what if running a so called isolated ground wire to each rail and running them back to the central (star) ground? Would there be any issues w/ this? Just curious, I know I read it.

Yeah, there CAN be problems with this - mainly because no two manufacturers handle chassis grounding the same way. Especially the ProSumer stuff, where they will stick XLR's in the gear to make it look Pro, but don't know how to wire them to eliminate loops (chassis lug tied to pin 1 AND circuit ground, for example) Emu is another example, some of their stuff has PLASTIC chassis, who knows maybe it's better... If you common ground an entire rack rail to the star point, then mount all chassis to that rail, you've just created a loop possibility depending on how the gear is wired internally. Unfortunately, there is no way I can prescribe a "fix all" scenario here because of the non-uniformity of gear. The only way I know to do this is to take each piece of gear as a separate item, and use either its manual or actual measurements (preferably both) and determine how grounding has been handled, both in reference to signal and in reference to power - keep detailed notes for each piece of gear, modify the ones that need it, and generate a final plan of grounding based on the info you gather. The final goal is NO complete path between grounded units EXCEPT the one going to star point. The minute the ground ties anywhere else, there is potential for current flow in the ground system. That's BAD. Rane has a couple of the best papers on this I've seen, here's one of the main ones - http://www.rane.com/note110.html This is one of the many areas I also need to dig deeper into with my own gear, once I have a decent place to put it all - I know I have some issues with gear grounding, pin 2-3 reversals, etc, that I still need to track down. One "throw money at it" partial solution might be to use balanced power, such as the units from Equi=Tech or furman - Equitech's site is another goldmine of brain frying potential, but fun if you're masochistic - http://www.equitech.com/ Check out their articles/papers/FAQ's - a unit that would run most reasonable CR's would run around $1500 or so, as long as you're NOT trying to run the power amps too - if you're susceptible to blackouts a UPS in front of the transformer would add another $850 or so - that's the route I'm looking at when it reaches that point. To keep from negating the balanced power benefit, I would probably transformer couple the monitor outs to the power amps or get a bigger transformer so ALL electronics can be on it... Steve

Speaking of balanced power... When I had my main service (electrical panel) changed out to actual circuit breakers instead of the screw in fuses, I inquired about the "balanced power" issue. Either the electricians didn't really understand what I was saying, or didn't really know, or just couldn't explain it. ??? So how exactly or what is exactly..."Balanced Power"? What is the design structure of "Balanced Power"? Hmmm... Also, forgot to ask before I leave for the day...the layers on the floor...I've presumed that they should be "glued" w/ the liquid nails. If I decide to put the gypsum down, should I glue each layer? Or just give 'er a good screw job??

Balanced power - that's why I posted the Equitech link, check their FAQ and white papers area, lots of info there. floors are (mostly) just walls that are horizontal. This means that you will see noticeable improvement by NOT gluing successive layers, other than possibly a thin bead along the joist line to augment the fasteners. If you DO glue the layers to each other (full lamination) you'll get a lower resonant frequency, but it may not be sub-sonic without a LOT of mass - also, you will lose any advantage of separate layers having different coincidence frequencies, which is not as important but still measurable. Adding the gypsum layer gives you two "speed changes" going through the floor, plus extra mass - both of which will improve the performance... Steve

I was talking w/ a drywall guy lastnight, and he strongly urged me to "NOT" put drywall. He said if you put anything, to use the Duro Board (or something like that) that is designed for flooring. He said the drywall over time will crumble and turn to dust. The screw heads and everything else will begin to pop up, etc. So are you saying.."Do or Do Not glue the successive layers"? Thanks.

Steve, I checked out the Equitech site. Hmmm... Looks good...spendy little buggers... Hey, I checked out a few links. This may help some people... http://www.neccode.com or http://www.mikeholt.com (same thing) They have a code forum there. Also, here's a good info link... http://www.equitech.com/articles/enigma.html and... http://www.epanorama.net/documents/grou ... power.html

I hadn't heard of that problem - I wonder how long they store those full units (66 sheets or so) with each sheet laid flat under as many as 65 sheets of drywall (over 4000 pounds) and why the bottom sheet isn't dust... He may have been refuring to Durock - it's the fiberglas reinforced cement board that's used in wet areas and as tile backer. Mostly only available in 3 x 5 foot sheets, but supposedly made in full 4 x 8 sheets. Do NOT glue successive layers, either in a floor or wall - you want each layer to act independently in order to take advantage of differing coincidence dips and different resonances. I'll have to check out that code site - might be a big help to those without code books, thanks... Steve

OK, So when putting the drywall down between layers of subfloor, should I only use acoustical sealant between sheets, or should I also in addition to acoustical sealant, mud and tape the joints as if it were on a wall? Remember the drywall is contoured on the edges some for putting in the mud, so I would think the gap would need to be filled. What's your thoughts on this? Thanks.

I would run successive courses perpendicular to each other, mud the wallboard flush with a wide knife so you don't have any dips, and not worry about any caulk except at edges. If you put your top layer on, shifted by using the first course started with sheets cut in half lengthwise, NONE of your joints will be coincident. Go light on screws til the final layer, to minimise flanking through the fasteners... Steve

Edges meaning between the edges of each piece of drywall, or edges meaning the outter perimeter of the floor? BTW...any luck on the drawing for the steel studs / anti-sway brackets? Thanks, Aaron

I meant around the perimeter, where walls/floor/ceilings, etc, attach - where the bevels are in the middle of the field is where I meant to use a wide knife and mud, just so there is no unsupported cover layer. If you're using gypsum sandwich construction, I'd cut panels so there is NO bevel at edges. Drawing - just found your comment about "all three", so will try to come up with a swivel design. Just taking a coffee break now, then back to taking advantage of the nice weather, so will try to get to it tonight... Steve

"gators just won't give up, dammit all - just had an epiphany, though, and need to stop by Home Depot to check on some standard brackets - If I get lucky, you may be able to do your way brackets with off-the-shelf parts... Steve

Good Morning everyone... Well, I finally got the second layer of subfloor on (well almost all of it...2 sheets shy of completion). After careful consideration of putting the drywall in between layers of subfloor, I initially didn't plan on that much thickness of a floor. As it is, I've already lost several inches having to level the floor, and also didn't stub out the 2 floor outlet boxes I have for the additional thickness of another layer. So I've opted to use only the 2 layers of 3/4" subfloor. However, I may have a structure born anomaly. I may have not put in enough stringers in one portion of the floor, and when you stomp on the floor, it resonates some low frequencies. Then again, it could also be, I'm in the corner of the room, and it's building up in the corner???? I guess we'll find out soon enough. Hmmmmm....

Is your insulation actually snug against the underside of the floor sheathing? If not, might consider adding some R-11 batts over the other stuff... Steve

Yes, the insulation is up against the floor. I wanted to make sure of that prior to putting on the subfloor. BTW, the first layer is glued and screwed. There's not a way to disassemble it at this point without a chainsaw...literally. The second layer was also added over this last weekend, but screwed only along w/ some acoustical sealant sandwiched around the outer edge. (and of course all the seams, etc.) I think what it may be, is in that particular spot, it's 16" OC, and there's only 2 or 3 stringers in a 8 foot span (I'll have to look at the photo's again). Plus it just may be that it's in the corner, and you know how bass builds up in those corners.

Almost forgot... I went browsing through HD the other night looking for a solution for easily making anti-sway brackets for the walls to mount to the above joists...and found a few items... They had everything from "A" angle to stairwell angle (similar to a piece of L metal but w/ some awkward shapes cut, and also predrilled...5 1/4" long by 1 1/2"). Would something along these lines work for this?

Went there myself last night, everything I saw was too light except for some Stanley 8" "L" brackets at $5.50 each. If you were to use two of those (slightly mutilated) and drill your own holes, you could do a sway bracket that should work at almost any angle. I'll see if my freehand drawing skills :cry: can do this justice - Nope, had to do it with help :? Anyway, these brackets are nearly 1/4" thick steel, and bent the "easy" way, like you took a flat bar and clamped it in a vise and bent it over at a right angle. They are 8" on a side, so quite a bit will need to be cut off. If you keep them short enough, you might be able to keep them above where the ceiling wallboard intersects the wall which would make it easier. The rubber should firmly contact the sides of the steel stud cap, preferably at a junction where a stud is fastened. The top rubber does NOT need to touch the frame, all pieces should be glued to the bracket, and a gap left above the stud cap depending on ceiling joist span/deflection. If you need help in this area, holler - I think I already 'splained it though... Steve

Thanks Steve, I'll browse the isles again and see what I can come up w/ for the brackets. Seems like each store has something a little different. Ok, now I've got some additional questions on this near future framing... as you've seen on my other thread (and this one), the inner angled walls. In constructing these, what order should I build the walls? Should I (1st) build the outer perimeter of the control room. (2nd) drywall the inside of the outer wall. (3rd) Place the RC on ceiling joists, and drywall 2 layers. (4th) begin framing the inside angled walls and front speaker/soffit wall (5th) whatever materials will be used to cover angled walls. Do I construct in this order, or do I frame something like steps 1, 4, 2, 3, 5 or something different altogether? Not sure of the proper sequence for the construction. And if it is the first one I posted, how do I mount the inside (angled) walls above? To the drywall & RC? Liquid nail the heck out of it? BTW, perimeter board...as you've seen in the picture of the floor, and since it's raised some, do I run the 703 from the top of the floating floor, and run it all the way to the concrete? Or only the depth of the subfloor and 2x4's? Thanks again, I always appreciate the feedback and knowledge, Aaron

This may take a bit, besides the usual "gator quotient I'm on 12-hour graveyards and in the midst of selling a house (with all the attendant crap) - may take a few days before I'm of any use here, other than quick replies (of which yours AIN'T... :? ) At MY HD, those brackets were over with the gate hinges/hardware for some reason - they're close to 1/4" thick, about 1" wide, and 8" x 8" on the legs. Just a simple 90 degree flat steel brace. In fact, when I do those sway braces myself, I'll just use 2" x 1/4 flat bar and bend what I need (I have a bender that does up to 5/16" x 2", or 5/8" round stock, with dies for square corners as well as round bends from 1/2" up through 2"... Steve

I found the perfect mounting scheme. Similar to your idea w/ the 8" brackets (I saw them too), but only I used the Concrete Anchors. They are in an L shape. They are about 4" by 8 or 10", and much thinner than the 1/4" steel. Probably about 1/16" thickness, but very solid galvanized steel. They are also much wider (1 1/2" or 2"?) They're also cheaper...$2.96 each. I used the design that you posted, and it appears to be working great. I got 2 walls framed up this weekend. Any luck yet on the sequence of framing? Thanks, Aaron

Hey Steve, I've been pondering the ideas on sequence. Frame the outer walls first (control room). I'm using the steel studs for this. The inner splayed walls will go up after the drywall? This way for total isolation of the outer wall. The inner splayed walls, I will probably use wood as it will probably be easier for multiple reasons as well as support? The ceiling I'm still trying to figure out. Should I put up the ceiling after doing the outer walls? Then put up the inner walls? How do I secure the inner walls at the ceiling? Screw through to the RC, use construction adhesive? Also need a quickie answer on the perimeter board. Should I go all the way to the floor with it? The floor is raised up on blocks and rubber for leveling, so in some area's it's a couple inches. If I do go to the floor, should I use construction adhesive to glue the bottom edge to the concrete? Thanks, Aaron

More questions... Floor... The final flooring... Now that the subfloor is completed, and I've started framing walls...do I need to put the final floor on before hanging my drywall, or can it wait until after the walls are complete? Should I use hardwoods for the entire floor, or should I just do hardwood at the pilot seat area and carpet around the perimeter of the CR? Any suggestions or preferences on flooring? And how should it be mounted? Should I do a prefinished floor, or go with the raw materials and sand, stain, finish? What about the parquet stuff or...??? Thanks, Aaron