Long cable running audio has several issues to consider. While balanced cable more or less does cancel induced noise inerference working best if mic output impedance is <1000 ohms, there is a concern that cables used for audio these days are not terminated in the cable's characteristic impedance.
If this were video cable with no terminated impedance resistance at the receiving end, the video would appear smeared with video artifacts as the original information would arrive from the original at different times and not simultaniously as it should. Also, multibles of the original video would also arrive as an unterminated cable relects back some of the original to bounce back and forth between the source and receving end.
With video, these artifacts with unterminated cable is quite visible and worsens with length.
Used to be audio cable was rated at 600 ohms impedance and always terminated with a 600 ohm termination at the reeceiving end so information delays and reflection artifacts where minimized.
While these issues still existwith both video and audio, it's only video (and now digital feeds) that is still terminated in the cable's characteristic impedances (75, 50, 300 or some other impedance appropriate for the cable type being used.
Over the years I nd others have done listening tests determining unterminated cable with as little as 1 meter lengths are effected with audible artifacts if not terminated in a low impedance and driven by a source capable of high driving power.
The problem is audio cable these days usually does not have stated cable impedance and if it does it's very low (<150 ohms) requiring being driven and terminated low a matching <150 ohm resistance. Some microphones do have such low output impedance, but most IC audio output amplifiers have difficulty driving such loads especially long complex impedance cable types requiring matching output transformers having their own audio quality limitations or considerations besides be costly for the better designed ones so not a good solution in general.
Suggest knowing what the microphone driving impedance is and terminating the receiving end of long runs of cable with close to this to minimize the effects of unterminated audio cable. If balanced type, then a single resistor connecting the two signal leads is sufficient. If unbalanced (like coax) then place the termination resistor from signal to ground common at the receiving end.
Many years ago recording engineers at I believe called B&K figured this out and used 50 and 75 ohm coax driving preamplifiers to drive terminated cable at hundreds of feet distances eliminating all cable artifacts in the audio. I have done the same with a stereo preamplifier design driving up to several thousands of foot lengths of terminated S-VHS cable that also eliminates all cable artifacts delivering pristine audio regardless of distances.
See the S-VHS cable driving preamplifier on my site's accessory page:
http://www.sonicstudios.com/access.htm#24njv