Jazz trumpeter Miles Davis was a genius at using "pregnant pauses" in his solos. To me it had the same effect as playing the seventh step of a scale and leaving it hanging in anticipation of that resolving note. Talk about keeping the listener on the edge of her/his seat.

If one is able to experience complete and absolute silence for a long enough period of time, such as one might encounter in a sensory deprivation tank, one will find that silence has a "tone." The closest approximation of it that I have heard on a recording is the sound of Tibetan bells.

Regards, Neil