explain compression driver impedance plots to me

for the sake of high sensitivity, you have to sacrifice a large part of the quality
by "quality" here do you mean bandwidth / high frequency extension ?

or something else like distortion or some kind of a time-domain problem ?

because in a multi-way system with for example dedicated horn mid, horn HF and horn VHF bandwidth won't be an issue - but are there going to be other issues with trying to maximize efficiency ?
 
Thankfully our 'on board computer' does a good job of filtering/processing to something pleasing if not too egregious. 😉

WRT the Altec 511(A); yeah, it's pretty bad if the bell isn't damped and some form of Dr. Geddes' throat plug isn't used unless one sits at typical prosound apps' distances, so much tweaking required when wanting a high SQ. The 511B OTOH had specially designed rubber? inserts between the upper/lower diffraction vanes, which for the typical Altec aficionados has proven plenty good enough, though I use a large throat insert that smooths them out above ~2500 Hz and still needs a bit of shelving in my ~105 dB efficient system.
 
can you please elaborate on this a little bit more ?

i understand that slower expansion rate will present a larger airmass load causing higher compression and higher distortion but how do you see this in the impedance plot ?
In any case, a good impedance line should be smooth. Without spikes and dips. With a classic single hump of the main resonance.
If not, then the parasitic resonances are so significant that they affect the movement of the membrane itself. What then can be said about its linear displacement, and linear operation?
 
In any case, a good impedance line should be smooth. Without spikes and dips. With a classic single hump of the main resonance.
If not, then the parasitic resonances are so significant that they affect the movement of the membrane itself. What then can be said about its linear displacement, and linear operation?
what makes these resonances parasitic though ? if they were, wouldn't that show up as dips on frequency response ?