I wouldn’t let the fact that that the BH and MH were designated SR put me off, Jeff. The issue is the natural roll off of high frequencies caused by the horn configuration. I’m not familiar enough with them to specify at what frequency that attenuation will begin, but at some point the high end will stop making that corner and become reflective to some degree, and higher than that they just won’t get out of that “maze” at all.
Hence my earlier “thumper” comment.
Not that it’s necessarily a
bad thing, many players have successfully used folded horns for bass for many years, it’s whether or not that is what you are looking for.
Cabs wider than heads never bothered me personally; the “T” looks of the other way around drives me crazy though. Those vented 118’s would be a different animal than the BH/MH cab. When you can
see the cone you are getting the full range that the driver offers, and the high end “snap” is pretty much determined by which driver you use. A lot of 18’s will respond very similarly to 15’s (just move more air), and while “boomy” can happen if there is an issue with the enclosure/driver matchup, it isn’t limited to 18’s. Any speaker can get boomy, and IMO you aren’t any more likely to have an issue with an 18 over a 15. In fact, IMO speaker
size generally takes a back seat to things like xmax vs. total cone area, total cone mass and rigidity, etc
but there is a reason for the “stereotypes” associated with different driver sizes; smaller speakers are generally more high frequency sensitive and big speaker almost always pump more air.
Keep in mind the term “enclosure”. Everything that contains the driver is an enclosure, such as the room it’s in, and a lot of “boomy” issues are actually room induced. Big flat parallel walls can induce standing waves which will create pockets of eye ball rattling boominess alternating with pockets of almost zero bottom end response. You can actually move from one extreme to the other and
feel the phenomenon. Pretty trippy!
The 115 (and their “big brother” 215) cabs that I’m familiar with are the Sonic I40 and the 115S,M,V. I have a Sonic I40 cab;
I don’t have any pics of the cab opened. They look the same, but like the difference between a 200S and 215S,M,V cabs the Sonic I40 is rear loaded, fixed grill, and is basically half of a 200S cab. I know CLD has a 115V cab, maybe he can post a “naked” pick of it for comparison, but it essentially half of a 215S,M,V cab.
I think the 115S,M,V cabs are a
lot more practical and flexible, they front load, will accept about any 15” driver you want to put in and sound real good doing it, while the Sonic I40 shares the port ducting restrictions of the 200S cab which limits its overall utility.
Can’t share much about the 412 concept, the only Sunn 412 I have “hands on” with is the Sceptre, and I’ve had zero luck with that one as a bass cab.