The Dimension of Singing with Guitar: 2 Students with 3 Octaves?

  Maybe.... 3-5 in 50 students I get end up singing.

 This is usually the result of someone revealing that yes, they sing in the car or shower, and maybe they could sing and play guitar as well?

 Occasionally it's prompted by me asking a student if they've ever thought about singing, if they've come to the crossroads marked "starting to write music".

 I usually proceed after checking the student's vocal range.  That is to say not the traditional operatic registers, but where their pseudo tessitura is, where they seem to have note(s) that are musically useful.  

 Most people are limited to an octave or so, plus some notes in their falsetto range.  A second octave is usually available with practice.  Mixing through that octave, and into falsetto/head tone above that is usually fraught with empty "limbo" gaps.  

 This past week, I've curiously had two students that effectively can sing vowels from almost down to F# on the low E string, all the way past E 3 octaves higher without breaking, mixed into falsetto past E5.  E2-E5+, not necessarily great sounding, but pure tones.  

 One student seems to favor what I suppose is a counter-tenor range - he can squeak out ridiculously high notes out to maybe A5 while still being able to go down to maybe G2, the other a bari-tenor that can make notes below E2 while still going past E5.  Both sail through octaves mixed with smooth transitions.  Both should be able to get across singing that suits what they like to play on guitar.  

 It will be interesting to see what they do with what they have....