Aural Entasis - Simple Triple Time
Simple triple time (3 crotchet beats in a bar) is usually not played with strict regularity.
In this time signature, the second beat will come generally infinitesimally before the metronome.
The third beat ever so slightly behind it. This is called aural entasis.
Entasis is a technique where straight lines were imperceptibly bent into convex curves to make them appear even straighter and more perfectly proportioned. (The builders of the Parethenon used this technique).
We as musicians can give our music a speaking quality by applying this technique in any time signature but the waltz time affords us the best chance to grasp the essence of this idea. It is very important to remember that the three beats of a waltz are by nature unequal.
There is a reason why each beat in a measure of waltz time is unique and dissimilar.
There must always be a slight pause between beat two and three., because the dancers need a moment of suspension to help them slide through beat three, then swoop still further on down through beat one and on up to the next moment of poise.
The worst thing you can do is to play all three beats equally spaced out. The listener will not be able to hear properly. Both the player and the listener must be able to feel the sense of dancers lifting and whirling around the floor. Beat three must always lead into and through beat one.
Try this exercise:
Try pushing someone, literally placing your hands on their shoulders or back or chest and giving them a gentle push but firm shove on each downbeat (downbeat is the first beat of the bar). This is the movement the music is generating.
Now play, lending this feeling of push to each downbeat. This can be done in any time signature, not only in waltz time. You will notice that the feeling of push can be drastically improved through a slight waiting before each beat. This is what makes it a push rather than a hit- there is a sense of control in it.
Beat three must be delayed to help you move into beat one, but beat one must be delayed in order that we feel that push! Yes, it is possible to achieve both!
The same push that you will sense is what the dancers actually feel. They feely buoyed by that impulse.