More Bi-Wire Hooey, was re: Bi-wiring speakers

[Richard D Pierce]

David Y. Wang writes, in reference to Mr. Baptista's less than lucid
and far from correct description of back EMF:

>The EMF does exist, but no one seems to know of its magnitude.

Nonsense, absolute nonsense. The back EMF of the woofer fully and
completely accounts for the rise in its impedance at resonance. Period.
It's real damned simple. This effect (which is a consequence of the
mechanical resonance of the system) was well understood and fully
explained in McLachlan's, "Loudspeakers: Theory, Performance, Testing and
Design" first published in bloody 1934! It has been treated in nearly
every text and most articles dealing with the behaviour of loudspeakers
since then, a list that I feel safe in saying numbers in the thousands.

Precisely which "nobody" are you refering to, other than yourself and Mr.
Babtista?

Essentially, the "back EMF" is equal to the vector difference between the DC
resistance of the voice coil and the actual impedance of the speakers
at frequencies where the electrical equivalent of the motional impedance of
the driver is of any significance, i.e. at and near resonance.

It's very interesting (actually, not to those that know) to note that if
you were to replace the woofer (or any driver) with an equivalent
electrical circuit simulating the resonance (this would be made up
essentially of a parallel LRC tank circuit simulating the mechanical
resonance, with a series resistance equal to the voice coil resistance),
the impedance AND the so-called "back EMF" effects would be absolutely
identical to the real thing. Now that may come as a shock to those that
somehow assume that a voice coil moving in a magnetic field is somehow
magic and mysterious. There is, and has never been, any magic or mystery
here, at least not for the past 6 decades!

You guys couldn't have possibly read this bunk anywhere. You must have
made it up. This is really simple stuff. Any reasonable loudspeaker text
will explain this quite well.

>In summary, I still think the reduction of E-M interference between LF and
>HF signals by bi-wiring is more plausible answer for the possible sound
>improvement.

Any explanation would be more plausible given the satisfaction of at least
two conditions:

1: A reasonably strong and unequivocable demonstration that the
audible phenomenon definitely exists.

2: The explanation must be based on something other then the kind
of fantasy, bunk and utter nonsense you and Mr. Baptista have
fabricated. It must not only make sense, but it must be able to
make predictions and assertions that are testable in reasonably
unambiguous ways.

When you've made a serious attempt at these two steps, then you may come
back with a better shot at getting heard.

| Dick Pierce |
| Loudspeaker and Software Consulting |
| 17 Sartelle Street Pepperell, MA 01463 |
| (508) 433-9183 (Voice and FAX) |

[Richard S D'Ippolito]

In article <1pesae...@uwm.edu>, Richard D Pierce asks:

|> Precisely which "nobody" are you refering to, other than yourself and Mr.

|> Baptista?

Why, none other than yours truly, Richard D'Ippolito, the quintessential
"nobody" in the high-end net, who _does_ know the magnitude!

Rich