They range over a broad acoustic spectrum which, to us would spread from soprano to bass, but some frequencies are so low as to be inaudible to human ears. A typical whale song lasts about fifteen minutes, although they can go on for an hour or more. Often they are repeated, note for note, measure for measure. On occasion, a group of whales will join in for a singalong. And the songs may gradually change, by some mutual consensus, from month to month.
Whales are very good at remembering, and seem to have a great deal to talk about.
Unfortunately, during the past century, we've been interfering with their communications. This is about the frequency at which many of our maritime engines operate. But with all the noise that we generate in the oceans these days, they're lucky to hear each other even a couple of hundred miles apart. That's still not bad.