My real instruments here were a set of bongos and a shovel . I used FM syntheis to generate the sound (Sine modulating Triangle modulating Square) with the frequency of the modulating sinusoid being controled.
I used a drum loop here. The computer instrument was again FM synthesis with the sound being passed through a LPF whose frequency was being controled.
The instrument here was the STK mandolin where the amplitude and frequency were both controlled by my score.