Actually I'm uncertain if the TS param's would change at all
since they are based on "ideal" conditions anyway...
the motor charistitics of the driver are really fixed
so the motion of the cone and sensitivity are spec'd
against a known condition.... (1w/1m for spl) so the
box and volume will remain the same anyway....
The trouble is really the xover...
with the inductor's and cap's basically reducing
final voltage as well as filtering particular waves.
In addition any cap and inductor combination sets
the x-over in some harmonic (3x 5x) of the source...
There is also the phase relationship typical in LW
style filters that in effect swaps the polarity
of the hi pass section.
So your back to where you started the TS parameters are an
ideal - used best for enclosure design. Speakers have a natural
roll off and have some "order" of dynamic range. All these used
in conjunction to design an enclosure & x-over for a particular driver.
Volumetrics with the drivers Xmax or it's volume displacement
determining the box size. Dynamic range for the use of X-over
design.
Hi-Pass
Band Pass (if you use a midrange)
Low-Pass
Now then the hardest of which IS determining the final
load (in ohms) that your DIY speaker presents it's amplifier
(especially if notch filters are used...)
Now what was the question again?