Is it true that the XLR cables carry both an inverted and non-inverted signal, and that the inverted signal is re-inverted and additive, resulting in the 6 dB gain and good for long runs? Any externally induced noise in the wires is then out of phase (because of the last inversion) and self canceling - also good for long runs. I thought those were the technical reasons for XLR. How does the grounding scheme affect from a technical and musical standpoint?
Balanced cables
Do different brands/levels of balanced XLR ended cables going to and from differentially balanced components make a difference?