hi yet again Ken,
These are preliminary as I still haven't done a run with the driver entirely vertical (though final ought to be well within 10%):
fs = 22.83 hz
Re = 6.3 ohm
Qts = 0.37
Qes = 0.39
Qms = 8.63
Vas = 316.47 l (11.18 ft^3)
Sd = 890 cm^3 (I used JBL's 2235H specs)
Bl = 19.695 Tesla*meter
ETA = 0.94%
Lp = 93.01 db (2.83 V / 1 M)
Mms = 171.03 g
Rms = 2.9194 kg / sec
Cms = 0.2842 mm / N
Thoughts:
fs is perfect.
Vas / Cms is also very good, and lowers input power for my application.
Qts is somewhat higher than expected but I'll check later tonight whether the range is OK. As the spider is the same as 2235H and Mms is close, I'm wondering whether that's the surround as it's obviously stiffer than foam. Vas is ~32% lower than 2235H so that's a pretty good indicator.
However, the 2235H total Q is 0.25 which is still far lower than 0.37... this is baffling. I did note that the free air impedance peak is very high, nearly 140 ohms.
Fwiw, for your customers that use standard bass reflex enclosures in QB3 alignment, Qts = 0.37 is nearly perfect (Qts = 0.38 is perfect).
Motor strength is lower than 2235H, equivalent to 2226H. Strange as it's the same 0.75" coil in the same motor though the difference is not quite so large as the total Q.
Ref efficiency and sensitivity are excellent, equivalent to 2235H. I was a bit apprehensive about this and the results are reassuring.
Once I have the test jig set up, then I can use the measurement mic and obtain large signal distortion and guesstimate Xmax with a strobe light and ruler. Hoping for 7.5 mm+ at less than 10% THD... achieving this would be epic.
I'll run the calcs for the enclosures and biquad filters over the next couple of days though I am willing to make some accommodations for these drivers.
Thanks again,