c34 questions

[kkmiller75]

I have seen 2 distinct types of c34 enclosures. One is where the channel of the reflex is angular and one where all of the turns are radius. Are both or either of these original? I am trying to restore a pair and don't know which one I should be copying. Thanks in advance for any advise!
Keith

[Charley Rummel]

It's been a while since I've posted here - but seriously, folks! Good to post again!

The scoop-type of LF horn is one of my favorite designs, especially when it's done right-

My experience with the C34 has been that the earlier versions from the early to mid 1950's actually had curved panels in the interior of the horn path, and the crossover was mounted higher up on the back panel protruding into the horn path, whereas the versions from around 1955 onward to the end of the product life had flat panels comprising an approximation of the horn path; the crossover was moved farther down the back panel. I have one from 1955 with the flat panels, 001 system, and the crossover is mounted higher up.

I've met a number of people who've built similar scoop enclosures who say they're all hard pressed to tell the difference between flat and curved interior panels, so long as the path is constantly expanding towards the mouth of the horn. The one caveat I've been told in scoop construction that if there are any sections where the horn flare is even the slightest reversed, "turbulence" will occur in that part of the horn path resulting in attenuations and peaks in the wave propagation of that section of the horn.

It makes sense on paper to go with the curved panels and a bull-nosed edge on the interior partition that makes the horn fold in the upper interior of the enclosure. Go for it!

Regards,
Charley