A tempo is a pace at which a piece is performed. It’s one of the big challenges of conducting, both from a musical and from a technical point of view.
How do you choose the right tempo? And is there a “right tempo” at all?
The answer to this question is, quite obviously, no: there isn’t an absolute right tempo. Even when there are very specific metronome markings – like in Bartok’s divertimento for strings for example where you can even find how long a movement should last in minutes and second – a number of factors come into play, like the acoustics of the hall, its reverb or the size of the orchestra.
When you open a score and the only indication that you find is Allegro or Andante then is all up for grabs: these are primarily indications of mood and not of speed. That’s why so many recordings of the same piece can be so different in pace. Leonard Bernstein’s recording of the Adagietto from Mahler’s fifth symphony clocks at roughly 12 minutes; Bruno Walter’s – who had been assistant to Gustav Mahler – is around 8 minutes; according to Walter himself, Mahler’s performance was between 7 and 8 minutes. So wide is the spectrum of interpretation.
The right tempo occurs only when you manage to convince the orchestra and the audience that that is how the composer intended it. Is Karajan’s tempo for Beethoven’s fifth symphony right? Yes. Is Kleiber’s? Yes.
As long as you can make a convincing performance, yours will be the right one as well.
You will find in your scores that composers often alter the meter: 3/4 to 4/4 and back to 3/4 again – like Beethoven in the scherzo of his third symphony.
The meter change does not alter the tempo (and to stress that, the metronome marking in this example is the same as the beginning). In this case, it changes the energy of the music but the pace is unaltered.
As an exercise, you can try to set up the metronome at a certain speed and change from 3/4 to 6/8 to 4/4 and anything else you want.
Instant tempo change
An instant tempo change can occur for instance from a slow introduction to a faster allegro, as you can find in symphonies or overtures. You’ll find yourself in a few different situations: if there’s a break between the 2 sections, then that’s an easy one: you simply stop and give an upbeat in the new tempo (or a sharp downbeat if the bar starts with a rest).
If there’s no interruption you are going to need to stop your gesture before the tempo change, and wait until you have just enough time to give the upbeat in the new tempo. A good example would be the following excerpt from the second movement of Beethoven’s fifth symphony:
In this example, you will need to stop on beat two, wait, and use beat 3 as an upbeat for the “Piu’ moto“.
Transitional tempo change
As a general rule, the amplitude of the stroke is proportionally inverse to the speed you are trying to reach.
This means that if you are making a rallentando your gestures should get bigger, where if you are making an accelerando your gestures should get smaller. If you try to keep the same size of the stroke,
You need to listen for the momentum: whether you’re slowing down or speeding up, the orchestra will feel the tempo change and when that is set up correctly, it will carry it on consequently. Listening is another key aspect of being a conductor.
One thing to keep in mind is the direction of where you want to go. Try studying the very long and gradual accelerando in the last movement of Sibelius’ second symphony. It’s much harder than it looks. The longer the rallentando or accelerando, the more you need to pace yourself and have the big picture in mind or you’ll get to the new tempo way too soon.