If you overblow, you push the notes up in pitch and they seem shrill. This is why schoolkid's recorders always sound terrible - a more advanced player usually get get a better tone out of the same instrument. Part of this is due to the fact that if you start the tone off shrill, it will tend to stay there - it's to do with the balance of the overtones. Gently pushing from the diaphragm seems to give better tones that puffs from the cheeks - but it involves more breath control skills.

If you have any leakage due to fingers not sealing, this will not help.

The shape and positioning of the fipple may affect the purity of the tone at some parts of its range, also 'perturbations' in the bore have some effect on this.

Tapered instruments have a different % balance of overtones from cylindrical instruments.

You may find that some instruments will always be harsh and shrill, especially in the very top notes.

It is possible (perhaps it involves shaping the mouth and throat!) to THINK mouth blown instruments pitch and timbre to shape! Don't ask us! If we really knew exactly how it works, we''d be out there making a fortune teaching the secrets!



Robin