Superimposed Metric Modulation
The musical examples that I have contributed here
illustrate a sort of temporary change in time signature, or the illusion
of the tempo shifting momentarily when in fact it is not. I have chosen to call
this rhythmic occurance "Superimposed Metric Modulation" for lack of better
terminology, for that is exactly what it is. First of all, I say "superimposed"
because one pulse, or time feel, is layered onto another already existing
pulse, and because the layered pulse creates an effect of the time changing, I
say "metric modulation". But, because the original time base remains intact
(the tempo doesn't shift), and the second or layered pulse does not take the
place of the already existing pulse, I call it "Superimposed Metric
This rhythmic device, when used musically, as with
anything, can be very effective during certain places in a musical performance,
and can create a very cleverly deceptive shift in feeling, such as in a fade
out or out chorus of a tune or during a specific moment in accompanying
Let's take a look at the following examples.
In this example, I have used the quarter note triplet as
the vehicle to transport the feeling of one tempo to another. Because of the feel
in bar 3, it sounds as if the so-called "new" quarter note is a half-note
triplet, not a quarter-note triplet. The accented notes represent quarter
notes, as you can see. Also, I have reversed the imaginary tempo shift in
retrograde to illustrate the sound of one tempo going to another and back
to the original again. This helps in being better able to hear exactly what
happens; plus, once you go into a change like that, you have to be able to get
back out of it again.
Bars 1, 2 and 3 repeat to show a smoother, gradual
change and also to get a chance to groove a little for a moment, so that
everything makes more sense.
Here is another example of a modulation based on a
dotted eighth-note. The dotted eigth-note in this instance creates a 4 against
3 superimposition, which is the basis of the illusory modulation.
In conclusion, I hope I have shed some rhythmical light
on something that can be fun when used properly. And, if you find that you have
the place where you can use something like this, above all else, be musical!