XLR or RCA?

@ Dlcockrum, Hi, The last part of your post that your white papers said, Again keeping cable lengths short will reduce noise problems, I have been saying this for the last 25 years!, the fact of the matter, I have said this recently to a few members, It does not matter what I tell them, They believe some manufacturer that says other wise, or believe someone they know, It's to the point of, what do I know, right?, LOL!, I use 6ft speaker cables, all XLR interconnects are 1-meter length, no rca cables at all, all componets are true balanced from in-put to out-put that I use, been doing audio for 35 years, this a very long time, again, what do I know!

Noise gets in by direct capacitive coupling or electromagnetic pickup. In case of capacitive coupling shield can be very effective. Electromagnetic pickup is a little more complex. Shield is made of aluminum or copper - a non magnetic material and cannot protect against electromagnetic waves, but because of skin effect induced noise currents flow on the outside of the cable - shield. Skin effect works at higher frequencies but at low frequencies cable becomes effective antenna when length of the cable approaches 1/10 of offending signal wavelength. It means that if your cable is very long it will pick-up all sorts of electromagnetic interference in spite of shield. Balanced cable not only allows to reject common mode noise by being balanced but also by twisted wires inside - very effective against noise pickup (capacitive or electromagnetic) by exposing both wires to fields evenly causing same noise currents in both conductors producing cancellation. Keeping cables short is extremely important. My IC is 0.5m XLR.

Fully balanced signal is what makes live sound reinforcement buzzless and clean (except for electric guitar players with noisy single coil pickups)...with 100 foot (or more) snakes. You can take an unbalanced signal cable from a live musician's instrument pickup, stick that cable into an active "direct box" that changes it into the balanced signal the mix needs, and the result is clear as a bell. Also, the "future" is wireless live mixing (use an iPad).
When I play electric guitars I end up using long runs of unbalanced guitar cables (all the stomp boxes with an input cable and out to the amp) and have to apply small "micro amp" boost in there to unload the pickups and retain a modicum of fidelity. Nothing quite like a modicum of fidelity.

I used to own the McIntosh MC275 amp. Even though it is not fully balanced, I tried both RCA and XLR cables (Crimson Music Links) between it and my preamp at the time, an Aesthetix Calypso. I preferred the sound with the XLR cables -- I thought my system sounded fuller, with better bass than with the RCA cables. This probably had more to do with the Calypso, which is fully balanced, than the MC275, which is not.

In any case, why not just borrow XLR cables from the Cable Company or buy them from Music Direct, which offers a 30-day money-back guarantee? If you hear a difference and like it, then buy the XLR cables. If not, return them.

OK, in theory from this discussion should I take it that, all materials being equal, XLR cables are more resistant to noise than RCA cables? That noise can be both a function of cable length and EMF environment? And furthermore should I assume that more complex construction, at least in terms of shielding, should reap bigger benefits for RCA cables versus XLR cables? But what about wire configuration (I.E. metallurgy, thickness, shape) and dielectric composition? If you believe these are relevant at all, wouldn't they be relevant and affect the "sound" for both types of interconnects?

I understand and accept that many of these variables are highly application dependent (gear, physical location relative to EMF, ears and beliefs of the listener), and there is no substitute for "try before you buy", but I am just looking to see if I have grasped the relevant information in the discussion above...

kn