That's fantastic, thank you. I know that WTPro can predict THD and IMD. Any chance of posting comparative curves, please? The JBL paper you linked to suggests that drivers with shorting rings can reduce the 2nd harmonic by up to 15dB compared to drivers without which is not to be sniffed at, particularly if it can help improve some of the midrange incoherence I'm hearing with the Delta 12LFA.
I've measured the 12PLB100 driver and it works well too. Same deal: It needs the same crossover components as the Definimax 4012HO and the Delta Pro 12. Response from any of those three is similar, with vertical nulls in the same locations.
I'll be adding the Delta Pro 12 and the B&C 12PLB100 drivers as options in the next few days, as well as modifying the schematic to include those drivers in the notes.
Here are the distortion measurements, taken with an 8.9v (10 watt) drive signal:
Thanks, Wayne, great job and proves the efficacy of shorting rings as described in the JBL paper in reducing 2nd harmonic just leaving a bit of 3rd to worry about (or not).
If anyone wants the last two 12PLB100 on the shelf IN THE WORLD grab em now from Parts Express. I've spoken to B&C today who confirm that the driver is still in production but no-one else in Europe or the US that I can find with a search engine apart from PE carries stock. Perhaps someone can correct me.
B&C are going to get back to me tomorrow if they've been able to find any otherwise a UK disty has offered to order a pair with a 5-7 week lead time.
12PLB100 may not be the best choice from an availability perspective going forward.
As you said, the 12PLB100 is still in production, but they're slow-to-stock. It kind of reminds me of the JBL 2226H a couple of years back, when they moved production from the California plant. For about a year, new 2226H woofers were unobtanium. Glad they're readily available again, though not cheap.