Isolating Single Notes
This information is given from a lip-pursed embouchure perspective, but may be useful for other embouchures. Audio files are based on a 10 hole diatonic harmonica in C major.
Newcomers to the harmonica can find it difficult to play accurate single notes. Which is understandable – there isn’t much to aim at and the concepts of an airtight embouchure, good intonation and diaphragmatic breathing have yet to be explored. Ultimately everyone will develop their own approach to capturing single notes and some will find success sooner than others. However, if you are finding this skill elusive don’t give up. It is not that you will never do it; you just can’t do it yet. Give it time and you will get it. Let’s run through a few ideas that may help in your quest for isolating single notes.
Airtight
For the best tone and accuracy, first we need to eliminate any leakiness. This means placing your lips right round the mouth piece, with the corners of your mouth supportive but not rigid, and lips pushed slightly forward but not stiff. And drop that jaw. Remember also that each hole has the comb and dividers framing it. Your target area is nearly twice as wide as your eyes will tell you and pushing the harmonica into your lips will actually improve your accuracy, airtightness and tone.
Posture
Next you should remember to relax your posture. This includes your shoulders, neck, jaw and tongue. Make sure you’re not slumped or leaning on elbows either, as this compromises deep breathing from your diaphragm. If your cheeks are puffing in and out as you play, this also means you are not moving warm air from deep down in your abdomen and your tone will suffer as a consequence. Read more

The keys to success
How low can you go?