stealth audio explain bi wiring very well:
"The main reason to bi-wire is to eliminate interaction between cables carrying bass and mid/high frequencies;
There are two main types of bi-wiring: true bi-wiring, and internal bi-wiring.
True bi-wiring is running two separate sets of cables, each of them separate in its own jacket. All cables is this case are individually terminated with a spade or a banana plug. Internal bi-wiring is splitting the conductors (wires) inside a common jacket into two electrically isolated bundles and terminating each bundle with its own spade or banana plug at one end of a cable, or at both ends. Since the bundles are electrically isolated, this type of bi-wiring does eliminate the direct electrical (galvanic) interaction between the bundles, but the electro-magnetic interaction still exists (since the bundles are being run in a common jacket, close to each other). True bi-wiring eliminates both direct and electro-magnetic interaction, while internal bi-wiring still allows for electro-magnetic interaction. As we can see, only true bi-wiring allows to take full advantage of the bi-wiring concept. Therefore, in general, true bi-wiring is clearly superior to internal bi-wiring.
Thus, while our Dream speaker cables are internally bi-wirable, and the Cloude Ninety Nine speaker cables are internally bi- and tri-wirable with very little performance loss, true bi-wiring is still superior with these cables. With other STEALTH cables (Hybrid MLT, for example) we only only "true b-wire" - i.e. bi-wiring with two identical sets of cables, each of them separate in its own jacket.
Yes, it’s not as convenient as having the cables in a common jacket, but performance-wise, true bi-wire is better - because the main reason to bi-wire is to eliminate interaction between cables carrying bass and mid/high frequencies; having bi-wire cables in a common jacket - i.e. too close to each other - compromises the performance;
Please keep in mind that while bi-wiring is a good idea sound-wise, using higher performance cables in a single-wire configuration is usually better than using inferior cables in bi-wire.
In a true bi-wire configuration, you have 4 binding posts of each speaker; to each of them goes a separate cable; Therefore, you have 4 separate cables per side; It’s best for the sound if you keep all four of them separate. But if you do not like the way it looks (4 separate cables), they can be spiraled together and appear as a single thick cable which splits at the ends.
If your amplifier doesn’t have four terminals per side (for bi-wire) - we recommend fitting two spade lugs onto a single binding post at the amplifier end. If fitting two spade lugs on a single binding post is not possible - then the option is to order one set of the cables with banana plugs at one end, and the other set with spade lugs (and fit a spade lug and a banana plug on he same binding post). Another option is to order a custom bi-wire set both wires of which are factory terminated into a single spade lug"