--- In "John Lundsten"
<> wrote:
> 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.
That's good. Do you recall if you were using line or mic level
signals?
> As to stereo, it's generally considered one only needs about 20dB
of
> separation. Vinyl disc had about that much (on a good day).
Yes, but there's always that inner-audiophile striving for more -
whether it makes any actual difference or not! If you can get it, you
may as well take it!
> 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.
Good point.
> ** The perfomance will of course depend on the common mode
abilities of the
> gear & a low source impedance helps a lot too.
Most electronic audio gear performs reasonably well in those areas
these days, although some microphone have a higher output Z than
desired. The Royer SF12 stereo ribbon mic, for example, has/had an
output impedance of 300 ohms. Okay for short cable runs, but not long
ones.
The following is a moot point based on your measurements above, but,
from a theoretical point of view, I wonder what the nature of any
induced signal would be, from one channel to the other, when using
star quad? Would it be predominantly common mode, or differential?
That would depend on the inner topology of the cable and on which
pairs were being used, I guess. I can't visualise that right now,
every time I try to picture the inside of star quad I end up thinking
about DNA and a double-helix.
Doh.
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