[BEAR]

wrote:

http://tech.groups.yahoo.com/group/lweusersgroup/

A bunch of us LWE speaker fanatics are collecting and sharing
information about these early (1965-71) servo loudspeakers. These are
the ones that Steve Zipser (RIP) used to rave about all the time on
usenet with the flat frequency response from 20hz-20khz:

LWE-1 - a three way system using
a 15" CTS woofer, a 6" CTS solid-back midrange and an Electro-Voice T-
35 tweeter horn mounted in a speaker cabinet with dimensions of: 25"
H, 17" W, 12" D. Power rating: 50 watts. Resistance: 4 ohms.
Frequency response is 22 Hz - 20 kHz. SPL rated at 96 dB/per watt @
1m. Room gain control, mid and high level controls.

We've already got a lot of members (including Louis himself) sharing
historical data, photos, information about connecting the LWE's
negative feedback circuit to a suitable amplifer (we have clipkits!),
operating instructions, magazine reviews etc...

We have a growing library of clipkits, and now a manual from CM labs
with instructions on how to test any amplifier and fashion a clipkit to
enable the feedback network.

If you are looking for information about these speakers please come on
by and help yourself and if you have any information to share, that
would be great!

http://tech.groups.yahoo.com/group/lweusersgroup/

Clipkits?

Is this where the feedback for the amp is moved to the speaker terminals??

That's NOT "motional feedback", if this is what it is.

Motional feedback is when the actual position of the speaker cone is
derived, turned into an electrical value and that is used as "feedback"
to (hopefully) correct the difference between the input signal and the
speaker's actual attempt to follow it. For which there are limitations.

In particular, motional feedback methods up until now are primarily
useful for LF, and not particularly useful for midrange and HF.

In the case where the feedback is taken from the speaker terminals, the
effect is to *eliminate the effect of speaker wire*. Which is not at all
a bad idea. Of course, it is not perfect.

I'd take anything that Zippy said with a large grain of salt. I knew him
personally, and speak from that perspective.

_-_-bear