An old BEtter Audio proto, to be exact. I don't know if it's closer in performance to a Brahma, XXX, or BE first generation xbl subwoofer. I'm sure when used in a musical application (instead of using it as a means to set off car alarms...) all three are close to indistinguishable, even when you do turn it up a bit
Instead of just taking the woofer and doing the old "plug and play", I decided to do some critical listening to see how it measures up to the other subs I've had in my truck (and TBird before that).
A quick equipment rundown...Pioneer HU, aging 6.5" Type R's up front getting ~80 wrms/per (from an aging usx), and the xbl sub. I didn't build a box specifically for this sub, though. I used 2 enclosures I had when I was using an ED sub. The ported enclosure was around 2.7 ft³ tuned to about 32 (doube baffled and braced to hell) and the sealed enclosure was 1.75 ft³ and stuffed with 24 oz. of polyfil. Sub power came by way of a PG Tantrum 1200.1 (sub wired to 4 ohms). All this stuffed into the little cabin of my FORD (shut up you GM whores!) Ranger ext. cab.
I first dropped it in the sealed enclosure since I am and always will be a sealed kind of dude

The first cd I always use when doing my little pseudo tests on subs is Portishead "PNYC". The song I use is "Sour Times". There's a bassline in the song that has a gurgling sound to it. Lesser subs make this sound one notey and without definition. Basically, it becomes a rap music bass hit. This sub passed my first test. The bass line gurgled like Courtney Love after a late night with *insert porn star name*. Upper bass during this song was calling out my name, though. A quick cut on my decks para eq at 80 (narrow Q) cleaned things up just about right. I also had to lower the sub out to 0 from it's previous position of 1. That's all it took. LP'd at 60, a slight cut at 80, a slight gain adjustment, and I was rockin' and a rollin'. As I threw a good 20 more cd's at it over the next month it performed equally well. Even as I did a little output test, using the ubiquitous "Late Nite Tip" from 3-6 Mafia, it got obnoxiously loud and mean. Like my 15A, I was embarassed to play this thing that loud. A few more songs by NAS, NWA, Lil John, and Moby confirmed what I already "knew"...that this was a no nonsense driver on both sound quality listening and boom-boom listening. I even dropped in the AutoSound 2000 test cd "My Disc" and played an unclipped 20 hz tone...and I could both feel it and hear it (or maybe that was my insides grumbling...). Truly impressive.
Next, I dropped it in the ported enclosure. Dumb thing to do! Do you really need this much bass? The output in my truck (mind you, the sub is around 12" from my head) was ridiculous! With this much output, I started with the ©rap music. Deep, loud, and stupid loud. It really did hurt...kind of like going to a Pantera concert without any hearing protection

OK, a large diaphragm, high throw, ported and 1500 wrms...yeah, it's going to be loud. How does it sound ported? Well, as I put in selections by Alice In Chains, Portishead, Blue Man Group, and the Pirates of the Carribean Sdtrk., I noticed some horrific peaking. Awesome for street bumpin' hip hoppers, but not so good for an almost 30 year old grown man. After some major adjustments, I got it to finally blend...for the most part. There's only so much this little 3 band para can do

On the para eq, I had to use a fairly wide Q cut of 2 at 80 hz. I also used the "other" eq and cut 40 hertz by 2. Sub out was set to -2. LP down to 55ish. Portishead was gurgling once again. Kick drum beats in Alice in Chains "Unplugged" were more or less natural again. The Pirates of the Carribean soundtrack was still pummeling me with it's enhanced LFE. Knowing ahead of time that this enclosure was going to make this proto peaky as hell, and given the limited eq'ing options I had, this sub was definitely an admirable performer when ported.
In a truck or car with a hatch (basically, if the sub is in the vehicle with you...) this thing needs little power to pound like no other. Whoever thinks xbl subs need 1 Kw+ needs to have their head examined. For musical output (that still bangs), these things rock. My gain is set well below clipping (up until I hit 45 on the HU's volume...and I never went above 35 in my listening), my sub out was at 0 or below, and it still was too much if I turned the volume up a little too much.
One final note: When sealed, this thing was as uniform in frequency response as any sub I've used. The one area it clearly excelled against any of the other subs I've used was in upper bass response (much cleaner) and lower bass detail when volume was real low. With my HU at 20, I could still hear the faint detail of certain bass lines that are often times inaudible unless you adjust the volume upward. Altogether, the usual words/adjectives describe my overall impression of this (xbl) driver: transparent, drops low without any audible struggle, loud, musical..blah, blah, blah. Things you don't always hear when talking about the current crop of xbl subs: efficient and somewhat small box (1.75 for a 15" sub is small to me)...and it hit an audible 20 hz in car!
Geo, I hope you can get your BEA funding real soon. I don't know how much design you put into this particular proto, but it's really nice man. Sealed, in my enclosure, it's as close to plug and play as I've encountered in car audio
Now for the xbl component sets on the horizon...
Oh, gotta thank thumper for the loaner sub
