Bass arpeggiation

Fundamental structure: fundamental line on top stave, bass arpeggiation below.  Play 

One possible bass elaboration: I–IV–V–I  Play  as elaboration of I–V–I  Play .^[1]

In Schenkerian analysis, the bass arpeggiation (German: Bassbrechung) is the bass pattern forming the deep background of tonal musical works. It consists in scale steps (de: Stufen) I-V-I, each of which may span hundreds of measures of music in the foreground.^[2]

The bass pattern is an arpeggiation in the sense that its middle note (V) first arises as the fifth of the elaborated chord (I), of which it is the upper-fifth divider.^[3] It is only when it meets with the passing note of the fundamental line that V becomes an independent chord within the first one.^[4] See also Schenkerian analysis, The arpeggiation of the bass and the divider at the fifth.

The bass arpeggiation properly speaking consists in the three scale steps I-V-I exclusively, but it may be elaborated at a remote level: see Schenkerian analysis, Elaboration of the bass arpeggiation.

Sources

1. Pankhurst (2008), p.51.
2. Pankhurst, Tom (2008). SchenkerGUIDE, p.52. ISBN .9780415973977
3. Schenker, Heinrich (1979). Free Composition, § 1.
4. Schenker (1979), § 23.