I plan on building my second set of speakers. First pair was 25 yrs ago with bass port tuning and crossover done all by ear, no science--funny process for an engineer like me. This year I'm going to build an inexpensive pair of d'Appolito Midwoofer-Tweeter-Midwoofer speakers using the recommended 12 db/octave crossover at 2500 hz and the 2 4-ohm midwoofers in series. Any advice on tweeter selection? I'm leaning toward a pair of 1" silk domes--Northcreek d25-065, $36/pair. I think that the -1.5 db shelf from 1.5 K to 3 K is marketing crap, but the North Creeks do appear on paper to be a good value. Is there a better tweeter option for <$50/pair?

Are their any issues with putting 2 4 ohm midwoofers in series for 8 ohm? I picked up 4 Isophon's P170/30 cheap (<$10 each delivered) on Ebay.

If this project works well, I'll build some higher end speakers. If it's crap I'm only out $100.