Thanks for your support
I know about Selenium ST324 & ST322 tweeters. Their price is attractive but I think that you get what you pay. I mean that their response curves are not like CP-21F. Selenium ST324 have poor sound above 15kHz and ST323 above 12,5kHz. Their horizontal dispersion is 120 degrees, CP-21F have 140 degrees. Also CP-21F is 25W AES, Selenium TWs are 20RMS. I bought 4x Beyma CP-21F before year ago and their sound is fantastic but they are in 3-way systems with 4x Alpha 8 and 4x 15" Cerwin Vega woofers with crossover between LF and MF about 800hZ. If you want I can send you photos of them
Now I want to make speakers which have flat response from 80Hz-20kHz (THX crossover point is 80Hz) and four 15" Vega speakers I want to cut to 80Hz like subwoofers.
Alpha 8 have 89db/5kHz and have 2 peaks about 2,5 and 3,5kHz - 97db (it's 8db).
Selenium 12PW3 have 12db (min 92db/450hz, max 104db/3,2kHz)difference.
Selenium 10PW3 have 10db (min 91db/300hz, max 101db/3,5kHz)difference.
THX have requirement for 7db for surround speakers.
I have bad opinion about APT:50
Me and a frend of me used 2x Eminence APT:80 with 4x Eminence Alpha 8 in his car and HF was poor till we mount 2x CP-21F with L-pad

What's your opinion dB

Best Regards
Stefan