Irishgoldhound --
For me, I would say the sounds are "similar" in some ways, but different in other ways. It's hard to explain. Having detected with FBS machines for about 8 years prior to the Equinox (Explorers, and then the CTX 3030), I will say that the CTX is MUCH more similar to the Explorers/E-Trac sounds, than any of the FBS units are, to the Equinox. HOWEVER, there is definitely "Minelab DNA" in the Equinox tones. When running 50 tones on the Equinox (I ran the maximum tones on FBS also), many of the nuances -- the hints of when you have a junk target vs. a possible good target, etc. -- are very similar, at times, to FBS. In other words, if you are used to FBS, you will likely say at first "this sounds different," but then as you use it, alot of what you know about the audio clues in FBS, seem to "translate over" to the Equinox, and so you pick up the "basics" of the Equinox audio relatively quickly, as a result. But then, there are new things in the "dialect" of the Equinox's language that you will learn, over time, that are more unique to the Equinox itself.
I think that's how I would describe it...
Steve