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Re: [ARSCLIST] Cables- was Can 78s sound better than LPs?
It is important to note as well that the impedance of the loudspeaker
varies with frequency as well, both because of the resonate mechanical /
electrical frequency of the individual drivers as well as whatever the
passive crossover is doing, if there is one. Therefore, if I remember
correctly, if the source impedance of the amplifier remains pretty
constant with frequency, then by simple math the amount of power the
amplifier actually delivers to the load must vary with frequency as
well.
-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:ARSCLIST@xxxxxxx] On Behalf Of Mike Richter
Sent: Monday, August 28, 2006 8:25 PM
To: ARSCLIST@xxxxxxxxxxxxxxxx
Subject: Re: [ARSCLIST] Cables- was Can 78s sound better than LPs?
steven c wrote:
> When you folks are talking about "impedance" in relation to speaker
> (and other sound-system) cables...are you talking about the impedance
> of the cables as a transmission line? If so, does the frequency of the
> tramsmitted signal get involved at all? As well, does this mean that
> the impedances of both the output of the signal source and the input
> of whatever is being fed would have to be matched to the cables'
> characteristic impedance? I used to use 72-ohm transmission line to
> feed a half-wave dipole, with a pi-network output feeding my
> transmitter signal to the "house end" of the twin-lead (or 300- ohm
> line to feed a "folded dipole")...But is the upshot of this the
> possibility of having "standing waves" on speaker cables?
>
> Steven C. Barr
I won't speak for others, but for myself: No, I'm not speaking of a
transmission line. At the frequencies involved, simple RCL analysis is
quite enough. That also applies to the effect of coiling the wires:
there is no significant inductance and would not be even if the zip cord
were unzipped.
Of course, if one were generating and detecting a couple of hundred KHz,
there might be some significance. Barring parasitics, I'm not generating
them.
Mike
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mrichter@xxxxxxx
http://www.mrichter.com/