Pop songs are defined by various characteristics of structure and content. They are structured in time through a groove (or beat, or tempo, meaning roughly the same thing) and through an alternation of different parts of the song, for instance verse, chorus, bridge or middle part. A certain proportion of these qualities will make a musical piece recognisable, in a gestalt sort of appreciation, as a pop song.
To evaluate a pop song in terms of quality we need a little more than just groove and structure. That’s where elements as harmony, melody and lyrics enter the picture. For this article I will dig a little deeper into the harmony part of a pop song.
To keep anybody’s attention focused for more than just an instant, let alone the two+ minutes of a proper pop song, it is obvious that on every level of the song, something interesting has to be going on. As far as the harmony part of the song is concerned, I find this is best expressed by the song’s measure of the infinite sequence. The infinite sequence is a chord sequence which is so harmonically interesting that you can listen to it indefinitely. Pink Floyd’s Richard Wright was a true master of the infinite sequence, as he showed for example in ‘The Great Gig in the Sky‘, which was put on ‘Dark Side of the Moon’. It is interesting to note that, on the DVD of Masters of Rock, dedicated to Dark Side of the Moon, Roger Waters says about ‘The Great Gig in the Sky': “it’s a beautiful chord sequence.” On the same DVD, there is a fine scene in which Rick Wright is seated at his concert grand and goes on at some length about the beauty of the d-note pedal in the chord sequence of ‘Us and Them‘, which many consider to be one of the greatest pop songs ever written.
The interesting thing about the infinite sequence is that you don’t have to be a very accomplished musician, in terms of control over your instrument, to be able to produce one. Chord sequences are usually slow progressions, so you don’t have to play a lot of notes to bring them over to your audience. Also, they are instantly moody, they seem to effectively display some, usually dark and romantic, emotion. You can hear this in the following piece of Richard Wright, it’s the final section of ‘A Saucerful of Secrets’, also known as ‘Celestial Voices’. It was featured in a sort of musical suite on Pink Floyd’s 1969 tour, here in London’s Royal Albert Hall, where Pink Floyd was subsequently banned for demolishing the interior. Yes, that’s a real cannon, firing at the end of the piece.
That an infinite sequence is easy to produce, doesn’t mean it’s easy to play. On the contrary. The same things that make a chord sequence interesting: unpredictability, modulations and segmented bars, make them melodically difficult. This usually shows especially in the solo work that accompanies the infinite sequence. You can think of Neil Young’s ‘Cortez the Killer’, which is a perfect example of an infinite sequence, consisting of just three chords: E minor 7, Dadd9 and Aminor 7 (leading to an added sus4, but allright, I’ll grant you that one). These three simple chords open up vast melodic implications, and that’s where it really gets interesting… what if someone like Joe Satriana picks up ‘Cortez’? Watch what happens… no, better yet, listen!
Pat Metheny is considered one of the world’s best guitarists, and rightly so. The piece ‘Are you going with me’ is quoted on wikipedia as having a ‘basic chord scheme over a gently percolating bass vamp’ (whatever that may mean). Well, the chord scheme is not really that basic:
First of all, it’s in the key of C minor. That’s not really basic, because it’s a difficult key for a guitar player. It has no open chords, it’s not laid out very easily along the neck of your guitar and it’s quite a long way from the usual guitar keys of E minor, D (-minor) or C. Also, as it’s kind of circling around a not too steady center, with all those minor chords, lots of added notes and the final descent to a full dominant G chord, it actually doesn’t have a ‘key’ in which it is played. To spice things up a little, the key is augmented with a half step on the onset of the guitar solo, and another half step somewhere in the course of the solo. This, of course, opens up a tremendous amount of melodic possibilities, which is ideally suited for the kind of guitar player that Pat Metheny is. His enormous knowledge of scales and changes allows him to display an astonishing palet of beautiful phrases and notes that he fits perfectly to this ‘basic chord scheme over a gently percolating bass vamp’, only meaning that, yes, the whole thing grooves like hell. Here we go: