Hi Joe and All,
Wow, this thread is getting fun.
Nice picture. Like John, I'm in a quite a variety of facilities.
That one is beautiful.
Perhaps the most impressive wiring job I've seen is Zankel Hall, the new concert hall/multi-purpose room in the newly created basement of Carnegie Hall. 96-channels of BSS Soundweb and a mil-spec wiring job (whatever that means, it was artwork). I regret I don't have pictures to share.
Anyway, I see 8451 in specs and implementation all the time for both mic and line level signals. While audiophiles would certainly argue against it for a number of reasons, it is an industry standard.
Rick, the foil shield/drain wire is in contact and indeed connects to the ground of each piece of equipment like you indicated. However, I don't see this as any different than a braided shield as we see in most common touring grade mic cables. Could you expand on this a bit?
If you are suggesting that having a third conductor isolated from an additional braided or foil shield would be of benefit, I sort of understand. However, the problem we are most likely to see on pin 1 (the shield) is current flow caused by impedance differences in the two audio signal conductors being capacitively coupled into the shield. Having a third conductor wouldn't actually solve this.
The extra shield on the other hand could possibly minimize RF interference but it would still need to be landed to pin 1 or chassis on at least one end (or both if used with a phantom powered microphone).
This brings us to the next level of issues--the pin 1 problem, where pin 1 is foolishly connected by some manufacturers into the audio circuit ground instead of landed directly to the chassis at the point of entry.
All told, I think there are better cables than 8451, especially for mobile applications like taping and touring, but wouldn't hesitate to use it in a permanent install for mic or line level balanced connections.
Marc