I think you are optimistic Gene! Those speakers are rated at 100 watts, with an sensitivity of 87 db 1 watt one meter. They are -6db at 67 Hz.
Crossover first order to woofer, with a variable resistor following a 0.4 mH inductor, The inductor and variable resistor are bypassed by a 5 ohm resistor and a 20mfd cap which is also bypassed, so I suspect it is an electrolytic. The control I think forms a variable BSC control.
Tweeter crossover is second order. The enclosure seems to be ported.
I would imagine if you give it the gas the wire wound variable resistor would be likely burn up, but might protect the woofer.
I doubt those speaker will fill your space, but keep us informed.
I suppose this is a temporary set up.
However, if you want potent small speakers, you get the
ATC SCM 7 speakers.
One thing Billy Woodman knows how to do, is build very potent small drivers. These speakers sound fantastic with superb clarity. They can produce 103 db. Their -6db point is 60 Hz, and they will have more low bass then your JBLs as they are sealed and will roll off 12 db rather than 24 db per octave.
Price is $500 each speaker, so a set of 5 would set you back $2,500.
Now the -3db point is 90 Hz, so you could make a very nice 5.1 THX system with the crossover at 80 Hz. A good low Qt sub or subs would be required.
I believe this set up would outperform the vast majority of systems in use today for home HT
In these days of WAF you really should try and review such a system.
Those speakers are a really hidden gem and not used to anything like the extent they should.
Even though Billy Woodman produces fine studio monitors and vast exotic systems for Disney Hall and others, he told me that of all his speakers he is most proud of his little SCM7. And those are the speakers he uses in his home for his personal listening.
I have included the service manual for you latest reference speakers, with that much power you might need it!
You site does not have enough space to upload a two page black and white pdf file! So I have had to
upload it to my site here.