
All Tesoros have multi-tones imho. They aren't true multi-tones, but they definitely give a different tone (sound) for each level of conductivity.
Yes. Once you get to know a Tesoro machine, you can tell the difference on some things based on the sound. But the Golden Umax has distinct tones, if I recall four tones. When they first came out with the Golden, there wasn't much difference between them, but a couple of years ago they revamped their tones so that each of the four tones is more distinct.
For water detecting the cz21 has 3 tones. Took it out this weekend for its maiden voage and found a gold wedding band, some costume jewelry and clad.