Well I believe you guys, it just that he is looking at $1000 for 7Hz I just don't see it as practical.
I am not saying that if a person has the money he should'nt. I would not pay $1000 for 7 Hz
I can get 7 Hz for much cheaper than that.
I do realize the sound?feeling differance its the price that makes me say "practical" I don't know if you guys get my point.

I can tell the diff between 28 and 20 but how much am I ( myself ) willing to pay for it.
I just got to hear/feel 13-16Hz at least 100db or better. took a couple days for my ears to go back to normal and one day for for me to stop feeling sick to my stomach. We used two big SV subs to do it.

Must be getting old.

Gex,

you wanna know cheap.
My 5 1/4 WO is driven by a single channel of a pioneer HT receiver that was throwing the garbage and the one channel was shorting it out. I removed the one bad shorted channel and usea $20 diskman or my sons Nomad  and a surplus $5.95 crossover at 80Hz

thats my sub that I use in my trailer while its parked in my back yard. My son and I use it for our escape zone to get away from all the females in the house.  

thats cheap.

I go through dumpster at repair shops and sometime I fix it and sometimes I don't. other times I remove the good stuff for my parts bins.

Only in my own mind
I am breaking all my rule of use reuse with my WO32. Not even recycled screws in that baby.

by the way sorry I could not get you the answer that you needed
Gex

Match....Yeah Tools ARE required...you hit the nail
right on the head.  Also it helps if you have some good
noodles inside that other Head.

I'm thinking of building a 2nd WO & stacking it.
Four 10" drivers, 2 Horn mouths joining in unison.
Smaller than 1 SO