Sgtpepper9 - My canned answer for biwiring below (so I don't have to retype it several times a year).
Biwiring can, but not always does, make a noticeable difference in sound quality. Biwiring has nothing to do with DC resistance of cables as some state here, but has to do with intermodulation effects. The large magnetic field produced by the bass signal modulates the weaker magnetic field produced by the midbass / treble signal thus causing distortion.
This effect can be mitigated by sending the bass signal down one wire, and the mid-bass / treble signal down a second wire, the
TWO WIRES SEPERATED FROM EACH OTHER BY SEVERAL INCHES OR MORE. Just to clarify this point, at the frequency extremes the bass wire sees the inductive part of the crossover and only passes DC, no AC. At the other extreme, the midbass / treble wire sees the capacitive part of the crossover and only passes AC, no DC. Of course in reality, both wires see some low and high frequencies depending on the crossover slopes (first order, second order, etc.).
There are two prominent reasons why some people say biwiring does not work. One reason is the BUYWIRE reason; biwire cables where there is no separation between the wires (see above). The second reason has to do with the quality of the system itself. If the quality of the system is not up to the level of improvement added by biwiring, you’re not going to hear it. E.g., if you add a Wadia, Audio Research, full-up dCS stack, etc. CD player to a low or mid-fi system you’re not going to hear an improvement over the $99 Sony open box player (end of that argument).
From another prospective, with the exception of Mr. Bose (not high-end), Richard Vandersteen has probably sold more speakers total than any other high-end speaker manufacturer. His speakers are specifically set up for biwiring and insisted upon by he. Not a marketing tool, but a performance enhancement.
From my experience, my most recent two-channel setup was a TRIWIRED Hyperion system (938 speakers, Hyperion preamp and Hyperion monoblocks). Improvements were observed going from single wire, to biwire to triwire.
So, in your case you asked about biwiring, not biamping. Suggest a simple inexpensive test. Go over to RS or HD or Loews and pick up the correct length of cheap speaker cable. Remove your existing cables and listen with the new cable in the same configuration. Get a fix on the sound, and then reconfigure your receiver for biwiring. Listen again; cheap and you establish your own opinion of biwiring instead of getting everyone else's opinion, including mine.
As usual, IMHO all of the above.