A Cappella and the Creation of Rhythm 2: Homophony
In my first post on this theme, I looked at Cooper & Meyer’s theory of rhythm, and in particular the way that it frames the idea of accent as any musical event that draws attention to itself. Of the types of accent discussed in that post, by far the most important for homophonic a cappella styles is the harmonic accent. Where all voices are singing the same words at the same time, and the number of notes sounding simultaneously is largely constant, the primary means to alert the ear to a song’s metrical shape is the changing of the harmony.
And indeed, both the arranging styles and performance styles of close-harmony traditions have particularly focused on relishing the harmonic content: it not only regulates the rhythmic flow of the music, but colours its entire emotional shape.
However, this means that there are a number of scenarios on which the melodic shape makes it difficult to get the chord changes cleanly on the downbeat. Popular songs of the twentieth century were typically written with the expectation that the melody line would operate with a little independence from the accompaniment – the crooner generation in particular maintained that form of rubato whereby the tune is pulled around over a metrically stable backing. And the songs consequently feature melodic effects that see the tune arriving at the new harmony either ahead or behind the accompaniment. Nice to do when you have a band, but if your parts are working in rhythmic unison, this risks distorting the harmonic rhythm.
Specific examples of this kind of thing include:
- Anticipation notes. These usually occur at the ends of phrases, where the melody anticipates its final arrival on the tonic in the bar before it cadences. If the harmony parts likewise anticipate the point of arrival, however, it can just sound as if the arrival has come to early.
- Appoggiaturas. These come in all sorts of shapes and forms, and don’t necessarily cause a problem if they can either be sounded against the primary harmony or invite a juicy substitute chord – in the first case the dissonance helps create the accent, and in the second the colour chord does. But if the logical way to harmonise the appoggiatura uses the same chord as the previous bar, then this can cause problems.
- Syncopation. This is what perky, up-beat songs use instead of rubato. It has the same kind of function – shifting the melody notes back and forth so they no longer coincide with the beat points – but to a different expressive end. But again, if all four parts are doing this at once, it becomes all too easy for the ear to lose where the rhythm section would be playing if you had one.
There are a number of potential solutions to these problems:
- Careful choice of substitute chord. For both appoggiaturas and anticipation notes, you can make sure the attention is drawn to the right place by chord choice. For instance, in Passing Strangers, it would have been possible to have harmonised the appoggiatura at the start of every bar with the chord from the previous bar – but that would have effectively have moved the barline one quaver to the left, and the appoggiatura would no longer be that (since by definition they are dissonances that arrive on a strong beat). Using substitute chords that have more harmonic charge than what went before, on the other hand, intensifies the sense of accent on the downbeat.
- Re-voicing over the barline. One of the reasons for keeping harmony parts quite static in close-harmony styles is to keep the ear’s attention on the overall sonority of the harmonies, not on the individual lines. But if you need to make a metrical accent and you haven’t got a chord change to do it with, then ostentatiously revoicing the chord can do the trick. Usually this involves a strong move in the bass-line as in this example from Let The River Run, in which the tonic chord is anticipated in lead and bari, but the downbeat is asserted by the bass:
- Embellishment (breaking the homophony). Okay, so this is probably a cheap answer: got a problem resulting from the genre’s texture – hey, abandon the texture! But close-harmony traditions have range of devices well-suited to help, so it would be silly not to use them. Back-time is an embellishment designed to give syncopated textures something to bounce off, for instance, and since the expressive point of an anticipation note is precisely the singer’s delivery of a melody, it makes a very appropriate moment for a lead pick-up. The way that your embellishment strategy can be an artistic means to solve technical problems is a whole other area though...