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Discussion Starter · #1 ·
I'm about to build my 11'6" Wide, 7' Deep, 10" high riser and have a question on some of the construction techniques mentioned by DE back in the old HTB magazine.


This is for a riser containing tactile transducers.


DE mentions that the riser joists should be 2" less in height than the riser frame and not touch the floor. For example, my 2x10 frame would contain 2x8 joists that are level with the top of the frame and have 2" of space below them.


Does this sacrifice any sort of stability or make this a risk if a riser of this size will be holding 4 Berkline 090 recliners?


Does it matter if I do 16" or 12" OC spacing for the joists in this situation? I had planned on 16" OC to help with the 'suspension' of the riser.


I'm also taking his recommendation of only a single layer of 3/4" plywood and supporting the riser on the short sides only with rubber isolators. It seems like all of this in combination would definitely lead to a nice drum-like riser that responds very well to the transducer, but I just wanted to make sure I'm not setting myself up for a fall (literally, or figuratively!)


Thanks!

Jason
 

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Hi Jason,


Assuming that you plan to run the 2x8's along the short length of the riser, you should have no problems ar all. I don't have the tables in fronto of me right now, but I seem to remember that a SPF 2x8 can span something like 10' or 12'. That's to provide a floor without much in the way of "spring" to it - and you actually want some "spring" for the transducers anyway.


16" centers will be fine for your joists.


I built my riser the same way as you are planning (but, the depth of my riser was more like 6 feet - no big deal difference for the purposes of this discussion). I used joist hangers and screws through the rim joists (the 2x10's) to secure the joists in place. It's worked out fine for my riser (with 8 Aura Bass Shakers in it). I also used some rubber feet (the type that are screwed to the bottom of table legs) on the bottom edge of the 2x10's (both the short sides as well as the long ones - to avoid too much bounce or sagging) to keep the riser out of direct contact with the floor. This way, all the shaking goes into the riser. It's pretty neat to stand next to the riser and feel nothing while the folks sitting on the riser are moving around and saying "Whoa - what was that?"


I chose to glue and screw two sheets of 1/2 plywood to the top of the riser, using glue on the joists and between the two sheets of plywood. I also filled the riser with fiberglass insulation so that it would not act as an audible bass drum...


Good luck,


Dwight
 

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Discussion Starter · #3 ·
Dwight, thanks for your detailed response.


Yes the 2x8s would be running along the short length of the riser. I also plan to put in insulation in the joist cavities (although not directly surrounding the BK).


I'm going to look into putting the rubber isolators onto both the short and long sides of the riser frame. I may also add 1/2" of plywood to the top of the 3/4" if I find that it just doesn't feel as solid as I'd like. But everything I've heard suggests that 3/4" is perfectly adequate.


I guess I'll take it for a 'test drive' with the BK installed and see how it feels before I get it carpeted.


Thanks!
 

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Discussion Starter · #4 ·
One more question....

Would 3" decking screws be good for attaching the joists?
 

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Dwight,


Could you elaborate on the Aura install in the riser? Location of shakers, pro or regular, mounting method? In old house without riser I had my Aura shakers attached to each Berkline 090 with good results. New house is finished and theater construction began today and will include a riser for second row only.

Your thoughts and help will be appreciated.


Thanks,


Glenn
 

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Quote:
Originally Posted by CoolCanuck
One more question....

Would 3" decking screws be good for attaching the joists?
code wise probably not, screws snap ( rather easy) brands like Deck-Mate & others have some great screws but there are reasons you nail structual components like snapping screws during wood expansion and contraction, earthquakes, settling and so on. Tactile transducers add a whole new element


I nailed mine http://i7.photobucket.com/albums/y28...d/P8110074.jpg
 
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