Sunday, December 27, 2009

12 days of musical terminology, day 3 - suspension

Yesterday (hemiola) we had a rhythmic device. Today's is a harmonic device, but it's so ubiquitous that it's been in use from renaissance times to pop songs that are in the charts today. A suspension is actually a discord, but it's one with a very specific structure and purpose.

Here's how it works. Normally, if you have two consecutive chords, they are separate, so that all the voice parts move to the new chord at the same time (e.g. the first bar in the example below). Sometimes, though, one of the parts delays its move to the new chord, so that it hangs onto its old note while the other parts move to the new one. It's possible, of course, that the delayed note still fits with the new chord, but if it doesn't fit at all - i.e. it creates a discord - then that note is a suspension. When it finally does move to the correct note in the new chord, that's called a resolution.

For example, here are the last three bars of Messiah. The soprano part has a suspension in the second bar. The other three parts move to an A major chord at the start of that bar, but the sopranos hold onto their D from the previous chord, and only move to the C sharp (which DOES fit in an A major chord, unlike the D) on the third beat. (I am behaving myself here and not making jokes about the sopranos always being a bit behind...)



(Purists will point out that this is actually an appoggiatura rather than a suspension, because the D isn't actually TIED from the first bar to the second. I'll explain appoggiaturas another day. But if it feels like a suspension and sounds like a suspension, most musicians would call it a suspension.)

The example above is a "suspended fourth", i.e. the suspended note (the D) is the 4th note above the bass note of the suspension chord (A). This is the most common type of suspension, and its resolution consists of the 4th moving to the 3rd. Note also that the suspension itself is on the strong beat, and the resolution is weaker. (You will often be instructed to place a slight accent on a suspension if you are the part with the suspended note, so it's useful to be able to spot suspensions and anticipate this instruction.)

I mentioned that suspensions are also used in pop songs, and if you know any guitarists, they will know all about suspensions... at least, if you ask one to play you an Asus4 chord followed by A, you'll hear the second bar in the Messiah example above. Below is a fairly famous pop example - it's the intro to Merry Xmas Everybody by Slade. The suspension (Dsus4, or a D major chord with the 3rd note (F sharp) replaced by the 4th note (G)) is in the third bar, and it resolves to a D chord in the fourth bar. This same suspension occurs several more times during the song, in the two bars just before the chorus each time. (Listen to it here.)



And I can't finish without pointing out the best ever example of a series of suspensions. Look at the first page of Pergolesi's Stabat Mater. This has mainly suspended seconds rather than suspended fourths, but it has one after another, and really ramps up the harmonic tension. Lovely. (EDIT: I can't believe I forgot to mention the best pop example of a series of suspensions, which is Pinball Wizard by The Who - the suspensions start at 0:18 with Bsus4 followed by B repeatedly, and then there's a proper sequence of them during the verse.)

2 comments:

KeyReed said...

Well they MAY call it an appogiatura, but the suspension is prepared, 'struck' and resolved.

Jocelyn Lavin said...

I agree. I only mentioned the appoggiatura because I looked in the AB Guide to Music Theory to check I hadn't forgotten anything vital, and they claim it's not really a suspension unless it's tied. I presume I must have been told that before, but it had certainly gone from my head if so.