here is the link with horn specs (tractrix 350):
http://www.horns.pl/tractrix350.html
it should be installed to make it "time aligned" with bass drivers
As I understand the presented data, on 10KHz attenuation of -6dB about +/-30deg.
May be 2312 & 2308 or 2307 & 2308, would be better solution with 2426 drivers...
My experience with some kind of tractrix horn is that , for my feeling, it is too "beaming",
while mentioned 2312 & 2308 is fare more wide, even at over 10KHz.
In any case 2405 or some other UHF driver would be 'well-come'....
thanks Ivica
sometimes, horns seem to be more magic than science, or a trial-and-error procedure
the reason to use 2426s, is that I´ve got them for free, as a present from my friend Suso (thank you very much buddy!)
i´d like to listen to 2420s with original alu diaphragm, or something like that, but right now, economy makes me stay with my free 2426s
the horn data belongs to BMS 4550 drivers, though it is expected for the 2426 to behave in a similar way
my friend, who will make the crossovers, says that he´s confident to manage the 2426/tractrix HF attenuation with the XO, and obtain a "flat" response from the 2426, up to 15 khz (more or less) with 95 db or higher efficiency (I must admit that I have not checked the numbers, but I wish he is right about that, we´ll use 2x2205 LF drivers per cabinet, that are supposed to get 100 db, so we´ve got a little headroom here)
his advice is to try the speakers first, and then decide about the UHF driver (like the 2405), on top of the cabinet
I also think, like you, that we´ll have to use a UHF driver, because I´ve tried the 2426s at home with an altec 511B horn, and the HF rolls off very fast
and in a future, maybe a 2" driver and bigger horn for mids, lowering the XO point ...
Concerning the mentioned 2205 x 2 , it is expectable that You would get about 103~104 dB with 2.83Veff applied (single driver efficiency is about 97.5dB ).
The efficiency of 2426 with 2370 horn is from 110dB to 106 dB( from 5kHz) on axis, and expect-able -6dB drop would be expected on +/-45 deg with mentioned horn, so there is almost no headroom if would like mentioned horn 2370....
but I totally agree with You that only listening tests would give 'personal feeling'....
I have Radians in 2420 on 2370 horns. I made measurements today, they seem to go higher than 2425 (http://www.jblpro.com/pub/components/2370a.pdf).
They sound good to me.
thanks to everybody
we´ll begin the project after Xmas, I will keep you updated
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