[jazzman1945]

The first property of blues sound – its instability, constant modulation in pitch. This can be achieved in several ways (without mouthpiece) :
https://yadi.sk/d/nSSZRlALuBVCL” target=”_blank”>Blues touch

Narrowing and widening the gap between lips -from the beginning of record
The tip of tongue is inserted into the tap-hole and retracts back -after the first pause
Active soundless articulating the mouth, combined with a slight touch the keys to a minimum depth-after the second pause
For comparison, I blow the usual straight way , by pressing the keys like the piano; and even with a little vibrato, then I’m going back to the active articulation.