For a decent while (until I was 18), I had a pretty wide falsetto. I could reach two octaves above middle C; possibly more, I don't remember exactly. But then I joined a men's glee club and learned to sing with proper technique. Since then, my falsetto has shrunk considerably - I can only get it to about a C above middle C; above that it gets hard to control and warbly, and by G or so it's simply inaudible or impossible. Interestingly, over winter break (when I wasn't singing daily) it seemed to somewhat come back. Does it make any sense that singing "correctly" in chest and head voice would diminish one's falsetto? Is it possible that my falsetto is just now starting to vanish beyond age 18? Or is it possible I've done vocal damage that affects only my falsetto by singing tenor notes?

Some male soloists can sing as Baritone and Alto (falsetto) with very good voice quality in both registers. I have met one guy recently, he is a fellow from another choir and also a soloist.

He sang some parts as Baritone and other parts as Alto in the same H. Purcell Tedeum/Jubilate (I just sang in the choir).

It could be more difficult for Tenors to do both and I never met one, but no I'm not sure.

In any case, this is not a gift everybody has...

There's a Russian Bass who can sing in 5 octaves. I saw him on TV. U might get him on You Tube.....

I was the world's worst baritone in college (no range up or down) but I had a falsetto that was sweet - full strong and up into a Soprano register. My voice teacher said she hoped I was going to be a Tenor because heavy Tenor voices don't develop fully until the late 20's/early 30's.

Well here I am today 30 years later with a big 2nd tenor and almost no falsetto (as opposed to a head voice which get's me up into the lower Alto range - that's still there and I use it all the time - especially in Baroque pieces (this is also the basis for yodeling the moving between the full and head voices - trivia).

I've never heard a good reason but there is no doubt that as the voice matured the falsetto left..

Hope that helps

Ivan Rebroff was his name
born as Hans-Rolf Rippert, (31 July 1931 in Berlin, Germany -- 27 February 2008 in Frankfurt), was a German singer, allegedly of Russian ancestry, with an extraordinary vocal range of four and a half octaves, ranging from the soprano to impressive bass registers.