Most songs are in the usual rock metre of common or cut time although some songs are in ¾ or 6/8. At the end of some 4/4 phrases a ¾ or 2/4 bar is used to push the beat. The rhythm, in the first few albums, was typically very fast with its roots being spawned from British Punk Rock. As Metallica produced more albums the speed was drastically reduced and the punk beat was used less regularly in the place of slow rock ballads and standard rock drumming. Because a double-kick drum is used, the backbeat is extremely strong.
As with rhythm, Metallica became more advanced in their use of pitch and harmony. In their beginning albums, the pieces were most often in E, E flat or D minor (very common to heavy metal because of the range of guitars (E flat and D minor are played as E minor but the tuning is dropped to achieve a thicker sound) ). This was the case until quite recently (approx. 1994) where Metallica started to experiment with different chordal bases. Although Metallica based their songs in E minor, chromatic chords are used very frequently because 'if it sounds good, use it!'. Their non-modal styles of playing could also be attributed to their lack of formal musical knowledge (as with most heavy-metal guitarists).
Most vocal melodies are in E minor (or D or E flat), due to the singer's vocal range and are quite basic.
The Rhythm guitar often plays in unison with the lead guitar but usually the rhythm guitar is extremely basic because the vocalist plays the rhythm and complex chords would be difficult to sing and play at the same time.
Power chords (1,5" are used extremely frequently as any smaller intervals than fifths sound very muddy with the amount of distortion that Metallica use. Power chords were used less frequently in more recent album as less distortion was used.
The bass guitar often outlines the chords, only playing the roots but sometimes doubles with some of the guitar melodies.
Throug...