* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
Voice leading from IV-V We'll now consider the IV-V progression, thus allowing us to complete a I-IV-V progression. With chords a fifth apart (I-IV and I-V) there is always a common tone, so we have the option of using voicing with a common tone. Going from IV-V the two chords are a second apart, and have no common tones. In bar 1, we start off with a IV chord in close position: You might think that the easiest progression to the V is just to raise all the tones in the IV up to the corresponding tones in the V. While this is ok in some forms of music (e.g. pop music), it is not acceptable in classical music. Parallel fifths and octaves The bass-tenor interval in the IV chord is a fifth, and the bass-alto interval is an octave. This pattern is repeated in the V chord. These progressions are known as parallel fifths and parallel octaves, and should be avoided when writing homophonic and homorhythmic music. One correct way of voice leading from IV to V is to use the non-common tone technique, as shown in bar 2. Raise the bass (we're still considering root position only) and then lower the other three notes to the nearest V chord tone. Thus the tenor C goes down to B, the alto F goes to D and the soprano from A to G. Although there are still intervals of a fifth and an octave, these intervals occur between different pairs of voices than they did in the IV chord. The fifth was between bass and tenor in the IV but is now between bass and alto, and the octave was between bass and alto in the IV but moves to basssoprano in the V. Fifths and octaves are parallel only if they occur between the same two voices in two successive chords. Open structure Bar 3 shows an example with an open chord. We apply the rules for non-common tone voicing. The bass moves up to G, and we try to move the other tones by a single step. This is possible for the tenor (A to G) and soprano (C to B) but the alto has no V chord tone within a single step, so we move it by the smallest possible step, from F to D.