Those of you who have seen the little video clip on "After a Lesson" might recall when I said to John Peter that people get embarrassed when they have to sing. So I told him to look at me and sing when I moved in front of him. What I meant was that many times instrumentalists, even extremely advanced ones, get shy when they have to sing in front of others. It is interesting because, in my view after seeing this many times, they feel very exposed, almost naked, without the instrument. They all of a sudden feel a bit vulnerable. It is easy to 'hide' behind the instrument if that is your main way of making music. The musician gets used to a certain machine to produce the tone and the pitch and to do it just with the voice is difficult, for the reason that the person is not identified with the sound of their voice, and probably hasn't made a connection to their voice, as a vehicle for their music making.
I was showing John Peter that the trombone can play a note with the vibration of the lips and sing a note with the vocal chords producing two notes at once. To demonstrate that technique, the little excerpt that I played for him was from the trombone chorale in the last movement of Brahms First Symphony.
Then I mentioned the didjerido. Many people think that singing a note and playing a note at the same time is a very contemporary or avant-garde technique. But the aboriginal people of Australia were doing it thousands of years ago on the didjerido! (Many ancient people employed this technique.) Makes you wonder what is original and where it comes from...?