604 multicell horn

[Roland N R]

Loose 604 multicell horns are found only rarely on the used market and will not adapt well or easily to the emminence coax. A large 800 cycle horn in that coax would significantly hinder cone output and affect imaging etc. Adapting a smaller horn would not be easy... any throat inperfection (lack of smoothness)would diminish sound quality. I would use the coax as designed.

[GM]

This problem is solved by cutting out the OEM flex seal and moving it further up the diaphragm at the point that best complements the larger HF horn's roll off. At 800Hz, the driver isn't beaming so bad that the horn would obstruct it too much if it's round. Really, the HF horn will act as a phase plug, so there's probably a HF flare that would improve the LF's efficiency in the XO BW.

This would take some serious measuring to get right and you could probably buy several pairs of 604s for what it'll cost in a TEF system (or equal) and experimental drivers. Oh well, at least you could get a decent price reselling the TEF and the drivers could be converted to woofers by covering the area with a large DC.

GM

[Albert Allen]

GM you lost me about the flex seal?
what if I just used my 802's with the stock horn on the eminence? I was told it wont load the horn until around 2000 cycles but the Eminence really starts beaming of around 1500-2000 would it hurt the 802 to not be loaded until 2000hz but still use it at the 1000hz x-over point?

[Albert Allen]

I have received my Eminence 15CX coaxial 15" bass drivers and the adapters are on the way to mount my Altec 802 8-T's to them and I know the "built in" horn in the Eminence 15's will not load my 802's well enough for my desired 800-1000HZ x-over freq so........
My idea is to add a small muticell horn (with some ingenuity)to the Eminence to load the 802's better and wondered if I could find a couple of the little Altec 604 mulcell horns? I have no idea how the horns are attached or if they are removable at all, or if they were if I could ever find a loose pair?

I actually am considering even using a pair of small cast metal muticell's that are mounted to a pair of old Pioneer horn mid/tweeters I have....they look suspiciously like the Altec 604 muticell horns (at least from the pictures I have seen of them)

Any ideas or suggestions would be appreciated (yes I am still on the poor mans quest for the 604 sound)

Thanks

[GM]

If you look at a 604 you'll see that the diaphragm has a flexible surround coupling the driver to the horn to seal the VC and lower its HF output. I'm assuming here that the 15cx has one too. Regardless, if you put a larger horn on it you'll have to add one, just like the 604s, though not necessarily in the same place or with the same compliance. Like I said, a straight forward eng. exercise, but the Devil's in the details. ;^)

I don't know the tech specifics of the components, but for sure it won't have hardly any power handling in a critical BW and the 802's roll off slope will leave a hole in this BW, so not a good plan unless you're using them as low level nearfield monitors and can electronically EQ the response flat.

GM

[Roland N R]

Try the Emminence 12" coax... basically same horn as 15" coax but will beam at higher freq. But before anything try your 15" coax with your altec driver and hear how it sounds. Listen to a test CD check out for freq response and beaming. Then check it out with music and decide.