mystery comps

[Jody]

Helloo.
does anyone know what these are?
look interesting anyway.

http://www.speakerplans.com/forum/wh...opic26331.html

cheers.

[stephane RAME]

Hello,
Can be manufactured IPC.

http://cgi.ebay.com/IPC-LU-1060-SPEA...28132013r13310

Stéphane

[Earl K]

- I believe they were made by Jensen & vaguely recall they may have had a large ring radiator style diaphragm .
- I'm pretty sure Steve Schell would know the real story .

>< cheers

[teunos]

Hi,
I'm teunos, the owner of the IPC LU1060, and thanks for the tip it might be jensen, but how can i contact Steve Schell on here?

[Steve Schell]

Earl you're right on the money. These drivers were made by Jensen in both field coil and later permanent magnet versions from the late 1930s until at least the late 1940s. The design is a strange one, a re-entrant ring radiator. A large ring radiator diaphragm speaks to the rear, the wavefront combines to a single path, reverses direction and exits out through the center of the structure to the front. Some of these even had a square exit and a square cross section throat adapter to the horn.

Until Western Electric was forced out of the U.S. theatre sound market in late 1937 by the U.S. Government, they were the dominant supplier. Their technology was well protected with U.S. Patents which they enforced vigorously. Jim Lansing had copied the essentials of Ed Wente's compression driver design almost exactly, and was forced to change his phasing plug to a radial slit type to avoid an action from W.E. This threatening environment forced the other industry participants to innovate in order to avoid having the boom lowered on them as well. During this period Jensen came up with their re-entrant ring radiator and RCA built the center-suspended cone compression driver with radial slit phasing plug. Both designs were miles away from the W.E. patents. Later on when there was no longer the threat of legal action, almost everyone built the Wente type compression drivers.

Teunos, IPC stood for International Projector Corporation, which marketed complete theatre systems featuring their Simplex projectors. IPC purchased sound equipment from several companies including Lansing Manufacturing Company, later Altec Lansing, Jensen and probably others.

[teunos]

The funniest thing is that i bought these for 5 gulden each on a flee market,(Which was the old currency before the euro, which is about 2euro's each) and now they turn out to be pretty rare and valueable. But thanks for all the information, i'll be looking out for Jensen.