From the B&W website, under speaker cables B&W Group North America Service & Support - Frequently Asked Questions - B&W
What is bi-wiring, and should I biwire my speakers?
One useful and comparatively inexpensive upgrade path to consider is called bi-wiring. In some speakers the connectors for the low-frequency (bass) driver and the high-frequency (treble) tweeter are separated out, being linked only by short metal plates that can be easily removed. By using twin runs of speaker cable from amplifier to speaker, it’s possible to address each set of drive units independently of the other. Typically the cables are joined together at the amplifier end, to simplify wiring, although some hi-fi amps now provide for independent output connectors, one pair for treble, the other for bass, to simplify wiring. This will mean you have a total of four sets of speaker cables running from your amp to your speakers.
What benefits can you expect? Bi-wiring doesn’t influence volume, bass depth or even midrange punch typically, it improves stereo imaging and focus, detail retrieval and timing, although the effects aren’t always uniform. Some speakers are designed specifically to do without bi-wire speaker terminals, our XT4 floorstanders for example, and are none the worse for it.
One last element to consider it’s worth getting any speaker cables you buy properly terminated rather than trying to fit bare wire into speaker connectors. Quality 4mm plugs (sometimes called banana plugs) will ensure your cable retains its performance over time by protecting the bare copper from moisture which could lead to corrosion.