Most barre chords are "moveable" chords, as the player can move the whole chord shape up and down the neck. Commonly used in both popular and classical music, barre chords are frequently used in combination with "open" chords, where the guitar's open (unfretted) strings construct the chord. Playing a chord with the barre technique slightly affects tone quality. A closed, or fretted, note sounds slightly different from an open, unfretted, string. Barre chords are a distinctive part of the sound of pop music and rock music.