[BC] Audio Cable

[Milton Holladay]

And heaven forbid that the strands of one wire in a pair should have a 
different rate of twist than the other, or that there should be different 
rates of twist in the L and R pairs, what with the subtle psycological 
effect of hearing audio that has been transmitted through such 
wires..Perhaps TomO is a victim and example of this twisting effect. ....<g>
M
----- Original Message ----- 
From: "Cowboy" <curt at spam-o-matic.net>
To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
Sent: Thursday, January 03, 2008 9:11 AM
Subject: Re: [BC] Audio Cable


> Wanting to be sure, so after doing a little fact-checking,
> by consultation with Mr. O.......
>
> Wed Jan  2 22:43:50 2008
>
> In recent years the industry has neglected that which
> used to be standard. Properly terminated audio lines.
> Recall we used to have 600 ohm matched loads.
> Today, we employ low impedance outputs and high
> impedance (bridging) inputs. While possibly convenient,
> the after effects cannot be ignored.
>
> High impedance inputs allow for greater crosstalk and
> ingress of foreign signals. This would ESPECIALLY be
> true of left and right channels being routed through a
> common connector. Disbelieve this? Remember old
> fashioned sinks with separate hot and cold water faucets?
> Today with a common spigot we can have any temperature
> of water from the cold to the hot. Read:Mixed signals!
>
> Most zip cord constructed of stranded wire employ twist
> of the same direction for both channels. This causes an
> issue with the velocity of propagation. Ideally the left channel
> should have a left handed CCW twist and the opposite for the
> right channel. This creates an equality where common mode
> rejection is greatly enhanced due to the inherent cancellation
> of the common mode induced signals. Of course, this does
> increase the manufacturing cost of the cable. We must also
> consider the connector assemblies. The suggestion of using a
> marker is Ludacris. This can adversely impact its shielding
> properties and capacitance, thus affecting the audio.
>
> The negligence in these matters no doubt arises from the
> fact that audio engineers and designers have had no experience
> with RF. Properly terminated transmission lines are essential
> for efficient and clean transmission. If we used the low-Z
> out (a tx) feeding a high-Z load directly (a tower) we would have
> high VSWR, poor bandwidth, etc.
>
> Whether it be audio or RF they key word here is "transmission".
> Attention to line length, composition and connectors is very
> important to ensure square wave performance, symmetry and
> quality reproduction.