NOOB Question

[timbo14]

Hi friends, please bear with me.  I have a 25'w x 19' deep media / family room, 8.5' ceiling so approx 4000 cubic ft volume.  I want to try the 4 sub approach to pressurize this room.  I have a flat roof home with 12" rafters, 16" on center.  Will this void be adequate to mount down firing subs on my ceiling with the backs of them open into this void or would I need some type of "baffle box"??  Each rafter space would have more than 35 cubic foot of volume.  I currently have a few QSC pro amps that I could drive them with or purchase 2 of the Dayton SA1000 amps.

Where to put them?  in corners? 25% in from each corner?   Can't really do a "crawl" with this approach?

Tim

[ThomasW]

Hi, and welcome!

Yes you have adequate space. There are two ways to do your subs

One is to use drop manifolds as seen in the image below




The other flush mount as seen in the image below




Regarding the 'crawl', sit in the listening put the measurement mic in the locations where you want to put the subs

Use your QSC amps they are perfect for this project

[timbo14]

Thanks Thomas,

I understand placing a sub in my sitting position and moving around, but I am thinking I need multiple subs for my room.  I have a 12" HSU now, but want to flush mount in the ceiling.   Thinking of 1/4, 3/4 in from side walls.  Not sure I need front and back but have heard more=better..  =)

I would flush mount and just have the rear fire into the rafter void.

[timbo14]

I could also slide something like this into the rafter space and use a grill cloth over it

[ThomasW]

The sides of those boxes would be problematic. A flat baffle #2 above would be your best choice

[timbo14]

Thanks Thomas, much cheaper..   

the "lid"... ceiling is drywall nailed to the rafters with acoustic tiles glued to it.   Any concerns there?   I don't need a screwed plywood ceiling?

[ThomasW]

Nope no problems with the ceiling as it is...