and our "Unda Maris" organ studio.
Seeing that her playing lacked direction I suggested,
"Take only one mode,
say Pentatonic - all black keys -
and improvise something interesting."
We set the timer for two minutes
and she began to play in a Pentatonic mode.
As time passed by,
I observed the reaction of my other students.
For about 90 seconds they seemed to be absorbed by the music,
they could hardly blink.
But then something happened
and their focus was lost.
When the student finished playing,
I suggested to her,
"Change the mode or the texture or the rhythm
no later than after about 90 seconds."
It's like in a good action-oriented movie -
every bit is somewhere between 15 and 90 seconds long.
The general rule of thumb is this:
If it's starting to be boring,
it's already too late to do something about it.
Make a change when it's still interesting.
That's how you keep listeners glued to your improvisations.