Greg Simmons wrote
You can make a two channel microphone cable using a single length of
Star Quad cable; one pair of inner conductors per channel.
I am uncomfortable with that idea because I like to keep the two
channels shielded from each other for maximum stereo separation.
Theoretically it would be possible for the signal from one channel to
induce a proportional current into the other channel, thereby
affecting the stereo separation and imaging. But that's the theory.
In practice, the Royer SF12 stereo ribbon microphone came with such a
cable and had no problems creating a wonderful stereo image.
I think you are being over cautious/through, I don't have figures to hand
but recall when I tested a 100m (330ft) reel of starquad used as stereo the=
Xtalk was in the -100dB region across the 20-20kHz range. ** And
considerably better in the highly audible 2-4kHz region. I've certainly got=
away with timecode & mono audio going down same cable the T/c spill not
being audible at all (this was using about 20m of cable.
As to stereo, it's generally considered one only needs about 20dB of
separation. Vinyl disc had about that much (on a good day).
Another benefit of using starquad wired to 5pin XLR's is that it can be
used as stereo with good performance on most occasions but if you are in a=
RFI hostile environment then it's possible to use it as a mono cable as
intended by having a pair of XLR3 -5pin adaptors available.
** The perfomance will of course depend on the common mode abilities of the=
gear & a low source impedance helps a lot too.
John L
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