SoundSplinter 15" sub questions

[Paul D]

I've lurked for a few weeks while trying to digest all of the good information about DIY subs. Some of you guys obviously put a lot of time and effort into helping us newbies -- thank you very much!

I'm putting together a home theater in our game room, which is about 4300 cubic feet. Although the sub will be used mainly for HT, I'm looking for accurate musical bass. I don't mind trading infrasonic capability in order to get musicality.

I've concluded the room is too big for a single 12" subwoofer so I'm looking at 15" drivers. Specifically, I have my eye on the frequently-recommended combo of the SoundSplinter RL-P15 and the Nady XA-900 amp.

My plan is to build the sub into the riser for the 2nd row of theater seating. The riser platform will be something like 96"x48"x12". This would give me lots of internal volume -- probably more than 20 cubic feet net -- but it would also require that a 15" driver be down-firing.

First question: Any problems with the RL-P15 in a down-firing configuration?

Second question: Since I have quite a bit of net volume to play with, what would you suggest as an "optimum" alignment for this driver? The usual limitation of "How big a box can you tolerate" shouldn't be much of a restriction if I can integrate the sub into the riser. The design could also accomodate any sane port length, if we want to play with vented alignments.

Thanks for your time and tolerance of another newbie sub question! -- Paul

[ThomasW]

I'm sure it's just fine since the suspension is sooo stiff.

Several people are running them downfiring without problems. Here's how it's calculated.....

DriverOrientation.pdf

The quick any easy way to get a definitive answer is just call SoundSplinter and get their blessing.... :T

I see little point in venting a box that big (but you certainly can if you want, a 10" port might be fun). I would seriously consider running a second driver, and using a very low crossover point, given the nature of the installation.

[KeithM]

I wouldn't vent a box that big. Get 2 and get a Linkwitz Transform if you need any more extension.

[ThomasW]

LT circuits are only used in small boxes to lower the "Q" and boost the LF output. His box even with a pair of 15"s doesn't need a LT circuit