Have 300b MB want a killer pair of Hi-Eff speakers

Looking to fill a 12'X25' room with a speaker that will do justice down to 38hz.

minus what dB? How big? and how much money do you have to spend?

Because that is going to take a huge cabinet and/or horn to accomplish with any meaning output.

I don't know if this still holds true, but back in March Renmeister said he had

"an $8k budget for speakers give or take a thousand"

. But, he has an interesting criterion in that

...speaker that will do justice down to 38hz (AND) must work 5+ feet from the back wall.

I think, true 38Bhz performance, not -6dB or more down, without wall/boundary enhancement is pretty hard to do without lots of power(or really high efficiency), self-powered woofers, or fairly large horn-loading cabinets.

In case others are wondering, it seems Ren's latest reference point is Avantgarde Uno's which have a self-powered (250watt) dual 10", long throw, subwoofer cabinet in each speaker that covers 18 - 350 Hz.

Bass wise, that's a tough act to follow with 300B powered speakers placed 5+ feet away from the nearest wall.