I was determined to see if i could try and measure some concrete difference only by changing only a mic cable
I used Room Eq Wizard and basically stuck a mic (sm81 into a RME Fireface 800) right in front of the tweeter on my speakers.i then ran some sine sweeps to measure the frequency response of the setup using different cable configurations.
1) 1 25 ft cable (planet waves apparently "oxygen free copper" cable)
2) approximately 200ft of cable consisting of many mic cables joined together, mostly cheap "Hosa" brand cables
3) more of the same but with the longest cable i could make at the time around 275ft, (~84m).
My results i found to be quite interesting. 25ft cable
I was not really expecting much difference between the cables because of mic's low impedance and obviously the difference is not huge, however i was surprised that increasing the cable length actually increased the high frequency response.