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Discussion Starter · #1 ·
I have a basement space 13' w X 17' L with 7' from floor to joists. there is a support post and duct work running across the width of the space at one end of the room. I'm considering putting the seating under the duct work and the screen at the opposite end. My concerns are effective sound insulation and working with low ceiling hgt. Can I build a functional home theater with the above mentioned obstacles? Any feedback will be greatly appreciated.


Andy Goldberger
 

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First, the obligatory...code restrictions...blah...blah


My second row of seating (on 11" riser) is mounted right below the soffit I built around the ductwork at the back of my Theatre. So, for the back row, floor to ceiling height is only 73". You wouldn't want the whole room this way, but people are going to spend most of the time sitting anyway. My brother-in-law is 6'2" and he sits in the back row without any problems.
 

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Discussion Starter · #3 ·
I don't plan on inviting any building inspectors over. I would assume the age of the house would allow me a pass on current code.


What did you do for sound insulation?


A. Goldberger
 

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I framed the soffit out of 2x2 with an inch or so clearance from the ductwork. Then I squished unfaced R11 between the 2x2s before 1/2" sheetrock. I also stuffed the area above the ductwork, between the joists as much as I could.


The biggest downfall, as far as sound, was probably when I put the heat registers into the vertical area at the front of the soffit. There is only a short (14") leader off the main duct to the register. I seem to get a lot of sound into other registers in the house from these. Some flex duct in the path would probably have been better. However, HVAC noise has not been a problem at all. That would have bothered me more.
 

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Discussion Starter · #5 ·
So you suggest flex line to service the HT. Do you think some type of cover could be used to block sound transmission back into register when using the room. Also what type of ceiling materials would you suggest? I'm considering a type of drop ceiling I read about recently that snaps together and requires minimal clearance. I figure I could put some insulation above the ceiling tiles for additional sound dampening.


thanks for the feedback.


A.Goldberger
 

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The theory behind flexiduct is that it the material it made of is not stiff and sound reflective, plus its easy to add a few bends. I've only used this kind of thing for exhaust vents, but a lot of people around here have used it for heat vents too.


There's a couple of sides to the fence about dropped ceilings. Some people say no way, no how. It can be tough to keep them from rattling. Others say they have been able to tame the rattling well, by either stuffing the space above with insulation, or by weighting the tiles. Personally, I went with sheetrock.
 

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Andy,

I've seen Jim's theater, and the soffit/ductwork are so well hidden, they seem a natural part of the space. Very nicely done.


I have a similar situation to yours, an 11 x 17 foot room, with the house main HVAC and a structural beam running "Port to Starboard" across the entire 11' width of the room. The support beam and HVAC take up 4' of the 17' at one end of the room.


During rough in, I agonized about where to put the screen and seating. I finally decided to put the screen under the soffit and put the second row of seating on a platform. The main factor was noise from the HVAC, and I thought sitting as far away from the ducts as I could would be better. I used double 1/2" drywall and 2 x 4's to cover the HVAC.


As it turned out, now that the drywall is in, I think I made the right decision. The screen will be nicely framed by the soffit, and I'll have maximized the headroom in the part of the theater where the people will sit. Speaker placement will be easier. as well.


I used flexduct, and put the vent as far from the main plenum as I could, with two fairly sharp 90 degree bends. I put the return down by the floor on the opposite side of the room. I expect the return will have the most propensity to transmit sound. The flexduct seems really quiet.


I've used suspended ceilings before, without rattle trouble, by adding R13 batts above the whole ceiling. The nice thing is, if you want to make changes, run new wires, etc., it's easy to do. I did have an issue with a really big resonance at about 60 Hz. Never could get rid of it. I'm going with drywall this time because I thought the tiles were a PITA to put up, the bars were never perfectly straight, the whole deal was expensive. Drywall is cheap and solid, but you have to plan all your wiring ahead of time.


Good luck, enjoy, you've got a nicely sized room for a theater.


Regards,


Tom
 

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I have a 7' 2" ceiling. I built a 8 1/2" riser for a sofa, and put 2x6 boards under the feet of the sofa. This allows the sofa to be raised 10" above the floor and is still comfortable to sit on (I find it more comfortable). I did this because of the low ceiling, I wanted the extra headroom for the walkway on the riser.


It is not attached to the building, so it was not inspected.
 
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