It employs ringing open strings above and below the melody line.

This is particularly used on open strings of a bass guitar.

The pitch of the open string is called the fundamental frequency.

It may no longer be feasible to tune the open string to its base tone.

Note that this will play a D minor 7th chord with the open strings.

The note then played is one octave higher than the open string.

These ring out with greater clearness when played on 'open' strings.

It is not difficult to pluck an open string with the left hand.

Such a note is said to be played on an open string.

The number 0 means: play an open string (not using the finger).