Hello Tom, most Melodica’s will tend to de-tune if played hard so I normally play at a moderate volume, I always play with enough air in my lungs so when playing soft the pressure is the same. It is much harder to play soft with and achieve a consistent tone than it is to play loud (at least for me). When I play live, I play through an amplifier and effect pedals so I can control the type of sound I am looking for. The air and volume needs to be consistent for the effect input level from the pick up. So in order to control the overal volume I use a volume pedal. Sometimes you have to back off a bit and sometimes I need to punch it (Solos) so a volumne pedal really helps when using effect pedals. I have noticed that my Mylodica, a Angelhorn in a wooden coffin would get out of tune if I blew a little to hard, a very easy melodica to bend notes. Unfortunately after bending notes to often it is now quite out of tune and I don’t really have the patience to take it apart and tune it. One thing that I found in my early days of melodica playing was that with a hose more air is available to the chamber and the intonation would be more consistent than if I played with a trumpet mouth piece at lower volumes. This also helps when circular breathing. I did play with a hard flex pipe (Hammond 44/hyper) for a long time but now play with a trumpet mouth piece.