Speaker Bi-Wire...which frequency does it benefit?

With an upcoming purchase of new Speaker Cable, I am considering going the Bi-Wire route.

Curious, when choosing a Bi-wire configuration...does it benefit more of the "Upper Frequencies (treble)" or Lower Frequencies (bass).

As a novice to putting together a good hi-fi system, I am looking to learn as much as possible...which will enable me to make smart purchase decisions.

Thanks