Dual Soundsplinter enclosures or ....?

[technimac]

I've got an open-plan house (with about 8000cu/ft of airspace to fill) and the HT area is in the middle of it.

Would I be better off to mount two Soundsplinter RL P15's in one enclosure, or to split them up and bracket the listening area with two separate enclosures?

Right now I have a Quatro 15 in a 6.5 cu/ft vented enclosure tuned to ~23Hz and a Peerless XLS 10/12"pr.

I'm thinking that with this volume of space to fill, two separate 3.5 cu/ft vented enclosures might be the best way to go, offering more flexibility to deal with any room nodes and other potential issues.

[Darren]

Unless you keep the two subs close together to couple them you could run into troublesome cancellation issues. I'd consider multiple subs only if you can keep them in close proximity unless you don't mind the challenge. Have you considered IB? I know... just thought I'd throw it out there

[Josuah]

As the original poster mentioned, multiple subs can make it easier to deal with room modes (another cancellation issue). I found my overall frequency response to be better when my subs were not colocated. If you want more SPL though, you should place them into the same enclosure.

[technimac]

Darren suggested that I consider an IB configuration for my sub needs.

So I visited the "cult of the infinitely baffled" site and had a bit of a Eureka Moment.
I got to thinking and then measuring.

There's space behind my living room wall in a 2'x4' chimney chase that runs for about 20' up the side of the house, and that is coupled to space above a t-bar ceiling in the basement. Total volume is about 320cu.ft. The IB drivers would have to be mounted on a baffle above or beside the fireplace, but it is definitely do-able.

I'm looking for the lowest tuning possible for HT. But uber-high SPL's aren't that important. I'd like to be " washed over" by the Sauron "ring-drop" in LOTR for instance, but not have induced-vomiting during the "Haunting".

I'm thinking two RLP 15's with a total amp-friendly load of 4ohms.

Got any recommendations on what configuration would be best to accomplish this?

Thanks for any and all feedback on this proposal.

Cheers, Bruce

[Josuah]

I'm not an IB expert, but apparently using a chimney/fireplace as your other side of the baffle doesn't work right because it ends up being a long tube. Something like that. The people at the cult can probably explain why, or maybe someone here.

[technimac]

Josuah,
Thanks for that information.
I should clarify what a chimney chase is here.
The "Chimney Chase" I was referring to is a framed 2'X4' extension that is attached to the outside of the house framing itself. It's kind of like a "bump-out" or "bay window". The actual "chimney" from the fireplace is a 10" diameter double-walled stainless steel pipe that occupies a small proportion of the volume inside the chimney chase. The chase could accommodate three or four of these pipes, but there is only one in this case.
So, no, I wasn't thinking of using the "chimney or fireplace" itself as part of the IB.
Cheers, Bruce

[Darren]

You might want to do some more research, it sounds like your drivers will be crowded with the 2 foot depth and an IB requires 10x the VAS of the drivers combined.

[technimac]

Darren,
Thanks for the reply.
Mounted on a baffle, the RL-P15's would actually be closer to 2.5' from the "rear wall" because the baffle itself would be attached to the interior surface of the 2x6 house framing.

Looking at a number of installations in the "Cult of the Infinitely Baffled" gallery, it appears as if there is less than 2' behind some of them, even ThomasW's, as shown here:
http://home.comcast.net/~klone-audio/FinishedBox2.jpg
In fact, he notes that, The lumber storage rack makes getting a picture with all 4 woofers impossible. It looks very cramped for the two subs on the backside of his manifold...

Imagine the chimney chase as a 2'X4'X20' "box" attached to the outside wall of the house, with the bottom 6' open to the inside of the house to allow for installation of a zero-clearance fireplace (requiring only about 2'x3' of that). In face, the RL-P15's could be installed anywhere, from the fireplace to the ceiling, on the 4' wide section of wall that has the chimney chase behind. In addition, the chimney chase framing has "friction-fit Pink Fiberglass R15" installed on the "exterior" three sides. Could that be a benefit here?

As near as I can figure, the Soundsplinter RL-P15 VAS is 5.76cu/ft. So for two that would be ~11.5cu/ft. An IB requirement of 10X VAS, would be about 115cu/ft for the two RL-P15's.

The total volume available for an IB, within the framed chimney chase and adjacent space above the t-bar ceiling, is ~320cu/ft. That appears to be enough for four RL-P15's.

I hope this clarifies my situation a bit more.

Cheers, Bruce

[Darren]

Hm, pictures would be nice to help, that and ThomasW over at the cult would be the right guy to answer the question about crowding the woofers. I'm concerned about the rather narow tube space you describe... might be ok though.

[Nick77]

I am also considering a dual rlp-15 IB. Will two drivers be enough for a 18'x20' room?

[warnerwh]

I just built this:[IMG]
[/IMG]

It is a tight fit with the 8" port in there. Outer dimensions are 36"hx48"Lx22"d. That's all the space I had to work with. There's two RL-P15D4s wired for a 4 ohm load going in. I used Birch ply to save weight.

[Sonnie]

Hey Warner... you should start a new thread for that behemoth. We wanna see measurements...

[warnerwh]

I'd love to see measurements of this beast too. I built it for a close friend who lives 200 miles from here. He has no idea how to do it himself. And now that I think about it I don't know how I could measure below 20hz. I have a Behringer DEQ 2496 and the Rives cd as well as a Radio Shack Spl meter.

I go up there every two or three months and could measure. Where do you get test tones under 20hz? I'm new to this and that's my first ported sub. I've built two sealed subs with Dayton RS Hifi 15s but that's it. If it wasn't for some help I received I would have been never been able to do it.

[Darren]

Nick77 wrote:

I am also considering a dual rlp-15 IB. Will two drivers be enough for a 18'x20' room?

You can certainly start out with just two, build a manifold that will house 4 and plug the two extra holes. I think you'll be impressed with just two but if you want more all it would take is ordering a couple more I personally have 4 in my 18 X 20 room which is open to the rest of the house and really couldn't imagine needing any more. Powered with an EP2500.

I've measured 120+ db in my room 15' away from the sub with just the sub running... Not sure you need more output than that