At one time Madison Pro Audio offered (through Steelsound), the Madison Executioner 21" inch loudspeaker for about 130 US..
Today Steelsound is now MusicSupplyCenter, but they don't seem to offer that driver anymore.
The only larger diameter driver with a HIGH Qts currently offered is the Knight 15.
http://www.musicsupplycenter.com/SearchResults.asp?Cat=47
Now there are also the Dayton IB 15's at PartsExpress (..with a lower Qts), and the Warrior 18 at MusicSupplyCenter (with a similar Qts).
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-455
Additionally, there is the Eminence Alpha 15 at PartsExpress with a higher Qts than the Knight, but with a lesser quality frame and motor.
http://www.eminence.com/proaudio_sp...l_link=ALPHA-15A&speaker_size=15&SUB_CAT_ID=2
(note that MJK has remarked on the the Dayton IB 15's vs. the Eminece Alpha's here:
http://www.quarter-wave.com/Project07/Project07.html )
Add. Note: I'm quite sceptical of all the eff./spl specifications for the Madison drivers - so take that value as extremely optimistic.
Anyway.. as you can see, NONE of the drivers are 21 inches..
So I was doing this search and up "jumped" this reseller on E-Bay:
http://stores.ebay.com/Hy-Tech-Gear_Subwoofers_W0QQcolZ4QQdirZ1QQfsubZ2009810QQftidZ2QQtZkm
Notice the Qms, Qes, and Qts for the 21 inch driver (..along with the price of course). Even the eff. seems about right, or possibly even a little low.
Well then, just a "heads-up" for those who might be interested in such a driver (..and no, I have absolutely no affiliation with the seller or even know anything about them).
Today Steelsound is now MusicSupplyCenter, but they don't seem to offer that driver anymore.
The only larger diameter driver with a HIGH Qts currently offered is the Knight 15.
http://www.musicsupplycenter.com/SearchResults.asp?Cat=47
Now there are also the Dayton IB 15's at PartsExpress (..with a lower Qts), and the Warrior 18 at MusicSupplyCenter (with a similar Qts).
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-455
Additionally, there is the Eminence Alpha 15 at PartsExpress with a higher Qts than the Knight, but with a lesser quality frame and motor.
http://www.eminence.com/proaudio_sp...l_link=ALPHA-15A&speaker_size=15&SUB_CAT_ID=2
(note that MJK has remarked on the the Dayton IB 15's vs. the Eminece Alpha's here:
http://www.quarter-wave.com/Project07/Project07.html )
Add. Note: I'm quite sceptical of all the eff./spl specifications for the Madison drivers - so take that value as extremely optimistic.
Anyway.. as you can see, NONE of the drivers are 21 inches..
So I was doing this search and up "jumped" this reseller on E-Bay:
http://stores.ebay.com/Hy-Tech-Gear_Subwoofers_W0QQcolZ4QQdirZ1QQfsubZ2009810QQftidZ2QQtZkm
Notice the Qms, Qes, and Qts for the 21 inch driver (..along with the price of course). Even the eff. seems about right, or possibly even a little low.
Well then, just a "heads-up" for those who might be interested in such a driver (..and no, I have absolutely no affiliation with the seller or even know anything about them).