After some prototyping, a new 12" monster has been designed to work extremely well for 3 way speakers or a 2 way using the the SEOS-15 and the BA-750 compression driver. The logical choice will be a powerful 3 way design similar to the Maximus-18, only smaller. Goals for this woofer: 1: Go low enough in a smaller ported enclosure to be used in a fullrange speaker. 2: Hit 80hz in a small sealed enclosure. 3: Massive power handling. 4: Really good X-max. 5: Easy to power even if duals are used in parallel. 6: Still have a good sensitivity in the mid 90's. That's a lot to ask for in a 12" woofer. But the beast has been made:
There have been thoughts of a MTM with the SEOS-15 and BA-750. Figure power handling of a couple thousand watts for something like that crossed over to a subwoofer. Believe it or not, a pair of them in parallel would be about 99db/2.83v. The Mid Bass Module you mentioned was another thought. B&C makes a 'very' similar driver that gets used like that: https://www.parts-express.com/bc-12bg100-12-neodymium-subwoofer--294-697 Some type of small horn set up or higher tuned enclosure would make these killer midbass monsters. What's the best frequency to tune something like that to?
Well if the parameters are similar to the B&C, then I'd say about 1.75cuft tuned to 30hz and 500watts would make an ideal MBM. That would give output over 110db down to 30hz. Someone could cross to subs as low as 40hz and output would be quite phenomenal. The impedance profile in the 40 to 150hz bandwidth would be a very easy to drive load as well. Could run two cabs in parallel off an iNuke 1000dsp to handle the XO'er and it would laugh at what ever your throw at it. It's basically the equivelent of a 12ohm woofer in that bandwidth and tuning. Keep the driver center low to the ground and ports above the driver or out the side. This will minimize floor reflections for crossing to mains around 150hz. If doing a slot port like the Stonehenge, then something about the inside width of a 15" box with one or two separator braces and 1" tall. It'll be fairly long and may require a bend unless the cab is made deep. About 19" long. All that would need to be checked agains your parameters. And Something like this, I'd want to confirm the tuning with a test box as people will want to cross low and 40hz would be getting close if the tuning were to high, and output would be down if the tuning were to low. So the tuning is somewhat critical.
If you design this 3 way, I'll be the first to buy it and post the build. It's exactly what I am looking for. Perhaps the SEOS 15 WG &CD along with MTM 12" woofers or 15" woofers. OR a W, M, T 3 way design with a 15" woofer, 12" mid, and SEOS WG &CD Just spitballin`
There's a 3 way being designed right now. The first might be a bit expensive, but it's going to be something very nice. There will be a few more that follow that will be cheaper.
Awesome, can you share any details? and when they may be available? I'll hold off on building the Sentinel V2 to replace my Tempests. The Tempest is awesome but im looking for a bit more power and more midrange. I can still buy the volts for my rears and heights and Fusion 6 or 8 for my other home tv. Not a theater but I still watch the occasional movie and listen to audio. It will be a huge step up from my htib onkyo's (which are hallow on the inside). lol
I would think the ideal MBM is a 4th order bandpass. Reasons are that it has an acoustic lowpass to reduce distortion on top, adds efficiency compared to sealed, but doesn't go dipole below tuning like a vented box. And with a really powerful motor driver and a light-but-decent-throw PR a 4th order BP cabinet can do some neat things. For example, here's a model LTD and I discussed on AVS about two years ago (never built, and can't build because PE discontinued the shallow PR that was small enough, light enough, and had enough throw to work in this design; a ported front chamber would have unacceptable port resonances) using the ur-XLS12 (830500). Total volume is 16L (about 2/3 a cubic foot) and it does some really neat things. For example, 1W/1m sensitivity in its passband is excellent for a cabinet of that size, at about 86dB/W/m. And yet, with 400W input (and >110dB output potential) wouldn't come close to driver xmax (Though that's at about it the PR's limit.) Just something to think about, if this woofer will work in a similar configuration.