Ill ask him which exact pieces he used.
If my memory dont fail he used :
A) 1601a ( or b not 100 sure) and 4001 with a 2·" to 1" adaptor to the horn. Crossover JBL N333.
B ) 1602 +4001+adaptor + custom crossovers from classic audio repro.
Marcos bought several units from C.A. Repro starting by 2 Hartsfields repros., you may send a mail and ask there which crossovers fits that kind of project.
The -3db response was never measured with test equipment , but
the response is clearly better than the original 40HZ or higher.
The sound of the bass is extremely deep and accurate on both projects .
I cant say if the 1601 or 1602 is better since are instaled in different setups.
My own project uses a 1603 , that is enough good but not as the 1601 or 1602.
I have the luck of buying a Tad Ls-10 or something. Like 5 years ago.
You may ask what is the ls-10. Well it was one out of 10 units produced
by TAD circa 1979. It consisted on a huge cabinet with 2 x 15" drivers ,
the first 4001 that's not the same as the new one and a wood horn plus the tweeter. It looked like the et-703 but with a different model.
Please remind that them were protos.
I bought them and sold to Marcos , we had the chance to compare this TAD protos . with the modified everests , everyone liked more the Everests . What is noticeable different is that the Everest were more natural and warmth without loosing dynamics. The tad's are slower and the bass extension was poor despite double 15" bass but still were great units . I think with some modifications it would get to nowadays dynamic requirements. What I had the impression were better than the modified
everest was the top octaves through the TAD tweeters . That tweeters beguilded my ears like no other I heared yet.
I have no experience with modern TAD horns or tweeters.
But if we only compare the horns on that speakers ( LS-10 and mod. Everest) , I remember the FIM CD of three blind mice catalogues
track 7 , And I Love You So, singer Yoshiko Goto .On the mods. Everests listening with closed eyes you swear Yoshiko was there even you can ask her to go out on a date
. No other speaker , with regular cone mids , electrostatics , horns or whatever you talk about give that sense of presence sometimes is scary ....