The Altec 604/5 series, Tannoy dual concentrics, and similar 1940/1950
speaker designs like the Jensen G610B, EV 15TRX, and University 315
are 2 or 3-way designs based on a 15" woofer with a horn-loaded
tweeter.

I've owned Altec 605A's, a Jensen G610B, and currently listen to
University 315-C's. The advantages of these speakers are that they will play
very loudly with little input (I'm using an NAD 2140, 40wpc), are very
reliable, and can sound very "live" playing certain kinds of music (music
that doesn't depend on very low bass and is performed primarily on reeds and
brass, such as my preferred music, the big bands of
Ellington/Basie/Henderson/Shaw and their various reincarnations).

I ran some measurements on the 315-C's about 25 years ago, using a WE 640
1" condensor microphone, GR 1554 analyzer, and GR pink noise generator. The
315-C's had a LF break point of 35Hz and had a table up 6db from 500Hz to
6KHz (where the weird decoupled midrange section of the woofer cone operates)
and then flat out to the HF limit of the WE microphone, 10Khz. This was
extraordinary for 1960, pretty good in 1975, and still not too bad today.
I hope to test these with more modern instrumentation, but not immediately.

Up until fairly recently these speakers weren't very expensive on the used
market; I paid $200 for the pair of 315-C's, including cabinets; since they
are quite happy driven by small amps the total cost of the system can be
pretty cheap compared to other alternatives.

Finally, the build quality on these speakers is very high; cast aluminum
frames, huge magnets, cones/suspensions/voice coils that seem to last
forever.

I'm currently refurbishing a JBL S8R system (LE15A/PR15/375/075) but with
a true 500Hz horn/lens replacing the one in the original; I know it will
be both louder and extend a bit deeper in the bass than the 315-C's but
don't know if I'll like it any better.

Mike Squires
--

Mike Squires (mikes at cs.indiana.edu) 317 233 9456 (w) 812 333 6564 (h)
mikes at siralan.org 546 N Park Ridge Rd., Bloomington, IN 47408