Okay...I did a search and though there is other SUB18 threads in the forum, none are in the DIY section so here it goes...

I'm building a home-theatre (mine) using clones of the M2 and desire to use the JBL 2269 driver as the basis for my subwoofer(s). That driver just has me so intrigued. I've generally liked JBL's LF drivers, particularly the 2242, which has always done me proud but the 2269...that thing is a monster! Whereas the SUB18 is listed as the compliment to the M2, I figured, why not? While I've worked with JBL (and Altec) for nearly half a century, I'm not a speaker designer, by any stretch. I'm thinking that a SUB18 clone would be a decent project.

Has anyone measured the thing (internal volume). My best estimate is that it is a 9-cubic foot enclosure. What are the ports tuned to? I'm not bent on necessarily having an exact clone either. While I do have depth available, since this will be in a home-theatre environment and they/it will live below the stage speakers, height will be at a premium.

Has anyone here cloned the SUB18 yet? Does anyone have it/them? If so, what are your impressions of it, including working in conjunction with the M2? I do plan to use it just as an LFE type subwoofer and NOT merely provide a bottom end to the M2.