The TD15M is a good bit different than the other drivers though, Fs is very low at 30.5 Hz, and Vas is way high at 405 Liters. The Qts is 0.27, giving a Qd for PiAlign of 3.703703... Zmax is less than 40 ohms.

So I could build a fine PiAlign box, but I'm not sure what would happen to the crossover. The TD15M is about 98.1db @ 1 watt, How would I choose a compensation network? My guess would be the 8db one. (this is for the PSD2002, btw, though I might upgrade to the JBL at a later date).

As for the crossover for the woofer, the TD15M is about +/-2db up to 1.5Khz, then climbs slowly to 4Khz, where it is about +3db, then rolls off 4th order. Would this imply I could just just a series inductor like with the 2226, or not? With that, I don't know whether the driver's own inductance (Le) matters or not, but it may be of note that it is very low, 0.2mH, compared to the 2226's 1.75mH.

I fully expect that I'd probably end up tweaking the crossover a bit later anyways, but any hints at a good starting point would be appreciated.

Thanks much

Charlie