Ron Capik wrote in message

Somehow you guys seem to keep poking sticks in each other's
cages. I don't see that any of this hand waving will get you out of
this poking match.


I think we enjoy to poking at each others cage. :-)


First I'd like to pose the question: with the thousands of components
and feet of wire that audio goes through between the recorded source
and the playback system (including room acoustic effects) why are
people so passionate about the few feet of speaker cable?

They are just plain ignorant.



Ummm, why? What's the magic about the reactance to resistance ratio
that makes "any two wire line" a transmission line? Seems to me you only
made a statement rather than an explanation.

There are two definitions of transmission lines.

1) A conductor or group of conductors, that carry electrical energy
from one point to another.

2) A correctly dimentioned conductor or pair of conductors, for
carrying RF energy from one point to another.


In my messages, I referred to:
1) as a "line" and to 2) as a "transmission line".

RF transmission lines have completely different characteristics than
low frequency lines. For example, an RF transmission line can be (all
by itself) a narrow band transformer, step up, or a step down and of
any desired tranformation ratio ("turns" ratio).

A 2.5 ft long RF cable on the ouptut of an amplifier, will look like a
dead short circuit at 100 MHz. But, if you short circuit the end of
the RF cable, it will look like a completly open circuit, at 100 MHz.

Transmission lines, connected properly, can become RF bandpass filters
or a notch filters. Two transmission lines coupled together slightly,
can become a directional coupler, that looks at the RF signal coming
down the cable but doesnt' see the RF signals coming up the cable. And
that is only the tip of the strange iceberg called RF transmission
lines.

As the frequency gets lower, and the ratio of XL/R decreases, RF
transmission lines lose their strange propertys. So, the question of
the day is: at what low frequency do two-wire pairs stop acting like
"transmission lines".

Looking at the XL/R numbers for 12 gage speaker cable, I see the
possibiliy that we *might* get more accurate results, by considering
them as "transmission lines" rather than a just as "lines". At any
rate, we are talking about *only a few tenths of a dB*, at 20 KHz.





2. Very long speaker wires MUCH longer than a wavelength, DO NOT
behave like transmission lines.


That right, if the resistance/ft is too high, it will be only a
"line".


[ see "Ummm" above... ]

[ see "There are two..." above...]


And we're still only talking about fractions of a dB difference ...at high
frequencies. Heck, opening the curtains or another person in the room
likely has more impact on the sound...


Yes.

[ see "At any rate..." above...]


[ returning to lurking mode ]


Excellent questions.

Have fun lurking.

Bob Stanton