Sounds mostly like normal cockpit background noise.
Different mics & audio ccts are more sensitve to different audio frequencies.
I doubt it's the patch lead.Noise cancelling mic's may help.
Try a recording using the same set up in a very quiet environment to see how much, if any, is generated by your equipment.Maybe some interaction with on board systems too?
The audio also sounds like it is being overdriven thus a bit distorted so impedance matching and maybe some form of attenuation maybe required.
Not at all familiar with the aircraft,sorry.