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BEAR BEAR is offline
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Default Yahoo group for LWE motional feedback loudspeakers made by Louis

wrote:
wrote:

BEAR wrote:

BEAR wrote:


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

snipo


I'm curious, does anyone know of an earlier motional feedback/servo
loudspeaker, or is the LWE the first to make it into production?

The Audio magazine review (1968) in the previous post makes it sound
like the LWE is the first to make it to production while there had
been previous prototypes.

thanks
-Sam


I'm not sure that this can be called a "motional feedback" speaker.
Before I say any more, I did download a patent and read some on the
Yahoo site. What he's actually done, and how it actually works is still
slightly unclear to me - didn't have much time to look at it all.

But, no matter how you cut it, there is bass boost applied to the
speaker to extend the LF response. The only question is how is this bass
boost generated/created, and /does it have any actual feedback?/

The idea of comparing an "idealized" speaker circuit to the actual
speaker and then applying the difference, is valid in that within the
limits of the driver's capabilities it will try to follow the
"corrected" signal... however later "servo" speakers all have used a
separate sensing device: extra turn in the VC, external inductive
pickup, accelerometer, etc... to generate the sense leg of the system.

In most cases that is massaged with circuitry to produce the proper
signal, and adjust the overall response (back to the "idealized"
speaker, but without an explicit model to compare to) with respect to
the input signal.

It would be interesting to implement the LWE concept on a modern high
performance large X-max woofer and compare its performance to both an
EBS (equalized extended bass response in a too small box) and to an
actual accelerometer or other inductive pickup method servo - all in the
same volume enclosure. That would be a definitive sort of test.

Thanks for bringing this LWE thing to light! :_)

Regards,

_-_-bear