Subwoofer orientation?

[justin.kerr]

I have been working on the design of my new theater, and I was wondering if anyone had any input as to sub woofer orientation/placement.
The room is appx. 18.5' W x 23' D x 9' H. I will be using 32 sealed 18" woofers.
I have 3 options that I am entertaining.
I am wondering which option should provide the best listening experience?

Option 1. place the 32 drivers against the back wall, spreading them out evenly, firing towards the front of the room.

Option 2. place the 32 drivers in the front of the room, with 16 facing towards the audience, and the other 16 rear firing, into the front wall, a bi-pole type of enclosure.

Option 3. Place 16 drivers in the back of the room, and place 16 drivers in the front, using the bi-pole type of enclosures.

I also have considered placing subs on the sides of the room, but that seems like a very problematic idea.

[John Simpson]

Ummm... 32 drivers? From what I can see, your biggest problem is going to be phase cancellation... there's going to be nodes galore in there.

Why 32? I have no doubt you'd be able to get the same SPL using 4 x 18" drivers in an IB setup.

It's not April 1, is it?

[justin.kerr]

Same spl with 4? Please explain

Yes I know that the phase cancellation could cause huge nodes, and with this amount of drivers, typical treatments will probably have a lesser effect.
Thats why I was hoping on a placement strategy, that would give me the best odds. lol

I thought about going with a huge IB setup, but was concerned with the limited placement, and adjustability.

[John Simpson]

If you go to the IB forums and read the results that guys are getting from 4 and even 2 IB 18" subs, matched to the right amp, I can't see why you would want anything more. Even 4 boxed subs with the right amplification would be more than enough for that size room (unless my imperial to metric conversion is shot).

It's not how much sound you can make, it's what you can physically deal with -- and what gives you the best experience. Have you used this many subs in the past? If so, what sort of amplification do they have? If you need 32 to do what you want, there's obviously a weak link there somewhere.

Tell us a bit more about your equipment and what you're trying to achieve...

[justin.kerr]

here is my current setup. http://www.hometheatershack.com/foru...-my-build.html

I have 4 EP 2500's with 8 18" drivers now.

To make things work the way I want them to, I need about 5 more db from the subs, and would like 2 more db's worth of headroom. In the new theater my L,R,C, and surround speakers will have 5 more db output than my current setup.
So I am looking for a solid 12db gain over what I have now, from 5hz to 80hz.

[John Simpson]

I just had a look over your build post -- impressive stuff. I'd thought at first you might be one of those cowboys that buy multiple $20 subs on eBay and then wonders why they all sound terrible.

While I still don't understand why you need so many drivers, I think I'm out of my league with your setup -- chime in you other mods!

[bpape]

If it was me, I'd just build another pair of what you already have and place 1 in each of the room corners. I'm not a big corner placement guy but when you can hit all 4, it's been proven to avoid some of the modal issues just as you're looking to do. If you consider each tower as a 'speaker', in theory, you should get an additional 6db from each tower so a total overall gain of 12db as you want.

Bryan

[justin.kerr]

Thanks for your input Bryan!

If I did the four corner approach, I would build 4 new towers, each holding (8) 18" drivers, in a bi-pole design.
The four corner way, would make it very easy for the rest of the room layout.

I wanted to E-mail you also about the room dimensions, while I am still in the blueprint stage.
Would it be beneficial to adjust any of the dimensions, I can go up to 16"'s wider, and up to 2' longer and of course make it smaller.
lol