Question: how to use dhd acapella choice?
Answer: Assure proper setting of the dial on the end of the Acapella. ... 
Sit up with good posture to use the Acapella. ... 
Take in a fairly deep breath and hold it for about 3 seconds.
Place the Acapella mouthpiece in your mouth. ... 
Exhale as much as possible (but not to forcefully) through the mouthpiece.