lugnut,
the sub concept that we will employ is very different than any currently on the market. so do any available ones measure up, only partially? and by that i mean in the bass extension but not in the stratification or placement of the output. and man, that is is the only clue you will get.
you will want a sub that crosses over at 30 hz at 12 and 24 db peroctave. one that can adjust output, phase and maybe even damping but that will be hard to find. one that will filter out of band energy and that will be even harder to find.
i do not know how your friend has them set up or what gear/cable he is using. your issue may be more one of bass quantity than extention. but unless i heard it with you i can not tell from this conversation.
howard,
by reinforcement we are talking about a very specific placement of the speakers in a given room. rooms can and will most times help extend the response of any speaker. i will help when you get yours.
b