I have never built anything similar ... so I am just goint to shoot in the dark ...
you can make the enclosure large to get a small lower end ripple, as you wrote. maybe install them in a wall of your listening room?
you could actively equalize higher Qtc speakers with linkwitz transform.
you can add a series cap to make the sealed enclosure a 4th order highpass system. that will also equalize the lower end ripple (but requires a high value NP cap).
you could make an aperiodic enclosure (resistive "port").
you could install the drivers in a transmission line.
Qts of both drivers is probably a bit low for open baffle, but you can still equalize them - probably no problem for such high excursion big Sd drivers!
The highest rated copper magnet wire that is realistic for use in a VC is 220c rated, and that's just for the coating. Most coils are wound with 200c wire, some with 155/180c. Coils made with bondable wire will usually overheat the bonder first and come apart before 200c, wet wound coils with VCB360 bonder will start to fail once they reach the rated temp of the magnet wire. In my testing, I've directly measured 230c from a voice coil winding with 220c wire before it came apart... 275c would be smoking!!!
"but you can still equalize them - probably no problem for such high excursion big Sd drivers!"
I do a 6-12 db octave crossover from 25-40hz and just up the gain to account for the loss, my crossover changes with material.. i have also eq'ed all the peaks out.
IS this changing the QTC of the box???? this is a big breakthrough for me if so
I do get it sounding good but i still think i need bigger boxes just to allow the drivers to move more freely
Relating to linkwitz transform (but EQing is essentially the same):
Strictly speaking it doesn't change Qtc but it precisely counteracts the speaker behaviour and the result is the same as a lower qtc speaker without eq.
Thankyou. I am beginning to grasp the concept.. if i increase the box size i will need less cut and less power
Electrical impedance result for a simple sealed box with Le = 1 millihenry and Re = 6 ohms:
With power compression:
Grey trace is for voice coil temperature = 20 deg C
Black trace is for voice coil temperature = 200 deg C
If by "long coil" you mean the lossy inductance option, then the value of Bl is adjusted by a factor based on the values of Le and Re. The values of Le and Re remain unchanged.
The model assumes linear operation, which normally means that the signals need to be relatively "small".