Questions about new build

You can experiment with weights on top, they WILL lower the m-s-m of the assembly. And if you can set the speakers so they stick over the front of your monitor stands enough so that the face of the speaker box is flush with your soffit WITHOUT the speaker or stand actually TOUCHING the soffit wall, that's just right. You want to cut the holes for the speakers less than 1/4" bigger all the way around than the actual size of the speaker box. If your speaker boxes have radiused front corners, you should make it even tighter fit to compensate for the larger gap caused by radiused corners (quite a few nearfields do this to minimise diffraction and point source re-radiation caused by sharp edges; this is a good idea for free-standing speakers, but NOT as good for flush mounting; although it's mainly the longer wavelengths reproduced by woofers that care about this, since tweets are more directional. Just remember though, that you do NOT want the speaker box in physical contact with the soffit wall (aka the baffle extension) As to SIZE of your baffle extension - I posted the formula for this in another thread about a week ago - http://www.johnlsayers.com/phpBB2/viewt ... c&start=15 My second post on that page has the formula for ideal baffle size, measured from center of woofer to edge of baffle... Steve

OK... this is starting to make sense. Would the low frequency cut-off in the equation be the same as the lowest range of the speaker? In my case I am dealing with passive Event 20/20's, so they have a response of 38Hz to 20kHz. By the equation, I'd be looking at 4560/38 = 120 inches... or 10 feet :) I am still trying to wrap my mind around what would make a practical speaker stand... If I build one out of 2x4's, it would be fairly light and therefore have a fairly high resonant frequency. Concrete pillars aren't very practical and would be tipsy. Jim

Yup, 10 feet would be total baffle width (per speaker) :? Realistically, make 'em as wide as you can - just be aware that if you make 'em smaller, and the edges then become conVEX (and they probably will) that it can cause somewhat of a horn loading effect, narrowing the sweet spot a bit. This can take away from stereo effect the further from the mix position you get (like the Producer's couch) but this can't be helped in a room that's too small for ideal baffle size, and probably won't be noticed by most people that'd sit there anyway :roll: Speaker stands - since you're out in AG country, check your local irrigation supply for 6" PVC irrigation pipe and fittings - use two flanges one on each end of a section of pipe, tops and bottoms of 1" MDF or 1-1/4 ply, glue together, drill a hole in top shelf, fill pipe with dry sand. Offset top plate enough so bottom one doesn't hit your soffit frame, screw to the floor, add mopads and speakers... Steve

Cool on the speaker stands... I can do that. Per the horn loading effect... I should still assume that "worst implementation of flush mounting is going to make your speakers sound better than the best free-standing mounts" right? Meaning... this is all worth the trouble, right? :) Jim

Absolutely. Positively. Totally. Maybe. (OK, I'm kidding about the maybe part... :wink: )

Steve, I was just reading a post for another person's studio where you warned that RC on a double wall does absolutely nothing... you also said that you wouldn't hang multiple layers of drywall from RC on a wall or ceiling because it will sag. Your explanation in that thread was that RC was for SINGLE walls and for only one side of the wall. I guess I'm confused... I was planning on using RC (single sided for walls and double sided for ceiling) for all of my walls simply because the timber is in contact with the basement floor and with the I-beams supporting the floor above it. It was my intent to hang 2 layers of 5/8 drywall from the channels. Is this not going to work? I was going to buy some RC this week and want to make sure I don't mess up what I should be doing. Thanks, Jim

You can put two layer of drywall on the ceiling or the walls. Go to USG's website and download their drywall construction manual to answer all your questions. Acoustic Assemblies - Publication SA200 You may need to register to access their library. :arrow: Also, when you purchase the RC, ask if they carry different gauges and if so, buy the heavier gauge (i.e. 20 ga, 22 ga, etc)

What I hopefully said, was that using RC (or any resilient mounts) in a double FRAME wall was a waste of time, money and effort. The separate FRAMES are all the isolation you need, the only place you should use RC or resilient mounts of any kind is where there IS NO OTHER MEANS OF AVOIDING HARD CONTACT BETWEEN INNER AND OUTER LEAF of a wall or ceiling. IOW, separate frames = NO RC. Staggered stud frames - NO RC. Separate inner ceiling joists with drywall only on one side = NO RC. Common floor/ceiling joists, where drywall or other mass is mounted to BOTH sides of each joist - use RC or RSIC clips to hang the lower leaf of drywall. Lightweight non-structural steel framed walls, with wallboard both sides of common studs = NO RC - the studs themselves are flexible enough to work as well as heavier studs WITH RC. STructural, or load-bearing steel studs are NOT as flexible (20 gauge) so if you have reason to mount wallboard to BOTH sides of these, then RC WILL be helpful for better isolation. I've said in several places that I'd NOT mount more than two layers of drywall on RC for a ceiling, but instead would use RSIC clips and channel because they're stronger. For a wall, you CAN mount up to 3 layers of drywall on RC; just space the RC a bit closer together. There's a new link (probably the same as sandersd posted) to the USG manual, the link in in the REFERENCE section. I've tried to clean up most of the dead links there recently. You WILL have to "join" before they'll grant access, no biggie. HTH; if not, ask again, but do NOT forge ahead without being sure; tearouts are a bitch... Steve