Balanced vs. Unbalanced interconnects?

Can anyone explain the sonic difference between using RCA type unbalanced interconnects and XLR type Balanced interconnects. Any help would be greatly appreciated.
If -- and only if -- you have a fully balanced circuit (not just XLR connectors), balanced interconnects are far better at rejecting interference and noise, especially with long interconnects (say over 15 ft.). This is why balanced interconnects are the norm in pro audio. For most home hi-fi applications unbalanced RCA interconnects work as well or better. The confusing issue is that many manufacturers fit XLR connectors to their amps and preamps without having the fully balanced internal circuitry. Without that the component is just "converting" unbalanced to balanced and, as if usually the case, a more complex signal path, produces higher, not lower noise. Hope this helps. Joel Tatelman.
Truly balanced components make use of "common mode rejection" to lower distortion artifacts. It is very easy to just broadly say that therefore, ALL balanced components are better than unbalanced ones...not necessarily so. One thing that is accepted wisdom in the industry, however, is that IT IS BENEFICIAL TO CONNECT AN UNBALANCED SOURCE COMPONENT INTO A BALANCED PREAMPLIFIER, WHICH THEN CONNECTS TO A BALANCED AMPLIFIER. In other words, it's very beneficial for the signal from the source component to become actively balanced by a balanced preamplifier.
Put it this way... I had a truly wicked ground loop from my cable TV connection. It completely disappeared when I installed an Audio Research LS-9 into my system and ran balanced interconnects to my (also balanced) main amp. Some folks say, however, that balanced equipment tends to 'soften' the sound of everthing it plays. This is true to an extent. Still very good sound...
I also have an audio research ls9, I found that after replacing the rca output to my amp with the balanced straightwire encore balanced interconnect - the sound improved and I HAVE LOTS MORE VOLUME/LOUDNESS WITH LESS ROTATION OF THE VOLUME CONTROL.