I noticed that, using some of the techniques that are used to play wind instruments like the trumpet – cornet, are also fine for the melody.
For example, if you play by inflating the cheeks and holding the base tongue, the resonance that is created is low in harmonics.
Instead, raising the tongue to the palate, pull the sides of the tongue to the upper teeth and thinking of playing forward, iol sound gets fatter and having more full harmonics.
I do not know if I was clear and sorry for my translation Italian – English.
As soon as I can I’ll post the evidence that I will do to explain better …..