Originally Posted by nube
I'm not surprised that so many here are recommending the FOTM (flavor of the month) drivers, and I think they could perhaps be designed in a way that performs well.
But, I think it behooves anyone seeking this type of build to go to one of the most experienced and respected authorities on the subject. As such, here's what bossobass has to say on the subject when consulting for people looking to do exactly what you're inquiring about in this thread:
By contrast, he doesn't seem to like the 18" versions of the Si or Dayton drivers for ultra low frequency content reproduced by sealed systems, as mentioned in other threads. Did I mention that there's likely also a pretty good place to get SSD-15 drivers, used very lightly and only for testing purposes, for cheaper than the Si and Dayton recommendations mentioned in this thread? Heh.
Thus, I see no need to reinvent the wheel. Giants have already created the template; all you have to do is stand on their shoulders.
I appreciate the kind words, but I was just about to post something similar to the OP's Q:
I'm very surprised actually that on here, we don't see much DIY templates that assure performance of other systems. In the PC world this is almost a given. Every month Tomshardware publishes the best bang for your buck.
It's precisely because the driver vendors come and go with such regularity that it's rather pointless to post very detailed templating for systems based on the reigning FOTM driver.
Here's why I don't get excited about the 18" (and larger) craze:
I still haven't seen any advantage to using an 18", except in very large rooms with very large owner output appetites (like notnyt) vs dual 15s, in fact, I see the opposite.
Taking the SI drivers, since they're the current darling and have been mentioned in this thread, a single 18 in 4 cubes vs dual 15s in the same box, the comparo goes something like this:
Using dual 15s you get:
36% more displacement
Double the power handling
Less distortion per dBSPL
Dual opposed stability advantages
Digs deeper (better <10 Hz performance)
Better in-room FR at crossover
The 15" is available now, the 18" is a prepay for future delivery
The added cost is around $400 for a 4x15" vs 2x18", a steal for the added benefits, IMO. I'm sure Seaton has come to the same conclusions with the SM I have in my own experiences for the same reasons.
2-Dual opposed subs (4x15"), amp and outboard EQ is a bit less than a SM and will best the SM by a noticeable margin in every category. If the amp and EQ are chosen wisely and properly set up, you'll get reference level to 5 Hz in most every room.