I've been recording bird sounds for a few years but I am no expert on
the technical side of this hobby. I use an Edirol and a Sennheiser
ME66.
Scott,
Where do I start? You've asked a technical question and need a
technical answer but here goes.
Non-technical answer - any mic cable will do. What you pay extra for
is ease of handling and appearance. Cheap cable gets very stiff when
cold and tangles easily but butyle rubber cable can be several times
the price but is easy to wrap or coil and doesn't trip people up. If
you are outdoors it should be able to withstand walking on or driving
over.
Technical stuff - if you must. The ME66/K6 outputs a low impedance
signal designed for 600 ohm systems. Simpler mics and electrets are
around 20,000 ohms, but the low impedance types under 1000 ohms types
don't pick up interference very easily. They are also usually
"balanced line", with two wires, one goes up when the other goes down,
so if any interference gets into the circuit, it cancels out. We were
taught that a BBC engineer once wired a microphone through a mile of
wire fence and the result was still broadcast quality. I think they
wired up a field telephone the same way.
Theoretically you have to feed a low impedance balanced mic through a
low impedance balanced cable into a low impedance balanced input which
presumably your Edirol provides along with phantom power, but you can
get away with all sorts of rigs so long as one end or the other is
balanced. If the mic and recorder/mixer is not matched the best
solution is to use an impedance matching balanced transformer. Mic
cable is always screened which is the ground conductor and is a sheath
of copper or a foil wrapping. They all work.
Cheap cable can be itself microphonic so if people are walking over
it, and that can cause some noise. For my run of two 100 metres cables
I chose the cheapest I could find and am perfectly satisfied, because
it is left in place and I only take the mics back indoors having
wrapped the cable plugs in a plastic bag. Don't be conned into paying
over the odds unless there is a good non-technical reason. The biggest
con ever is in silver loudspeaker cable. Copper cable is better than
any loudpeaker.
Electret high impedance mics are usually wired with a single conductor
and all cables have to be screened. The signal will deteriorate with
length as all cable is inherently low impedance and most cables are
microphonic (try tapping them).
David
David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce
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