A bent note is one that is not true to the note the harmonica was designed to play. A draw 4 on a C harmonica should be a true D note. A bent draw 4 is actually playing it in such a way as to produce a note that is just 1/2 step down or a D flat.
This is how some harmonica players are able to play songs that have sharps and flats that are out of their natural position in their keys. It is how they use a diatonic scale harmonica to play notes that are not programmed into their harmonica.
If you are learning to play the chromatic scale harmonica it is recommended that you do not try to bend notes. It will cause the reeds on your expensive chromatic harmonica to wear out much too soon and these are not as easy on the pocket to replace.
It is also how you produce a wavy or bluesy sound on your harmonica. By bending a long drawn out note while playing it you can produce a rather nice sounding emotional expression to your music. Many of the spirituals included in these lessons sound really good if you bend those long drawn out notes. It gives the song a kind of mournful sound.
How To Bend A Note
1. Only attempt to bend draw notes, not blow notes. For starters stay down on the low end of your harmonica. It is easier to bend a draw 3 than it is to bend a draw 8.
2. Make sure your lips are well moistened and the harmonica is placed well inside your lips.
3. Make sure you have an airtight connection around a single hole.
4. While drawing air through the hole (a good long draw at that) change the air pressure passing through your lips.
The Bear Went Over The Mountain