I suppose the best test would be something like a 60Hz test tone, well below the crossover but still at a frequency the speakers should have no problem playing.
Yes, that would be the test. However those drivers will likely play a little quieter than the two MTM drivers, as there is a huge inductor in series with those drivers which will have a significant DC resistance.
Shady Liked those speakers and they measure well. Standard measurements though crucial do not tell the whole story, not close. This is not a design I would have done myself. I say that, having walked the walk. I did something similar about 30 or so years ago, and ended up changing it to an active speaker, designing and building an active crossover and using two, two channel power amps. That was transformative.
Those lower drivers are to extend the power response. I would bet though that they actually need to play higher, but can't because of peaking of the FR.
This is where an active design has the distinct advantage. You can tailor the response of the fill drivers, and increase the power bandwidth and still have a flat FR.
I have used this design successfully in my home theater front speakers. This really increases the power bandwidth where it is really required and one of the design features that really sets them apart from the crowd.
On the thread by Sigberg audio, they make the same observation, and this is something we really agree on, and many other issues as well.
It is high time for active speakers to go mainstream and ditch those big receiver boxes with insane number of power amps driven from one power supply crammed together in one box. If ever there was a dead end that's it!
