pd43. List split and append objects in Pure Data

We can use a list of numbers to provide timed control signals to an audio generator or synth. Here, the audio generator is just osc~, but in general it might be anything.

We have a list of frequencies and delays. The freq is 110 Hz for first 50 ms, 220 Hz for next 50 ms, 330 Hz for next 50 ms, and 440 for the last 50 ms of this 200-ms audio.

The bang sends the entire list, and after each delay the list is smaller by 2. The first outlet of list split 2 will have the first 2 values of list, second (middle) outlet will have the remaining list. This is fed into list append, which is triggered by the delay. Since you are appending an empty list with the remaining list, the new list is the remaining list, which is again fed into list split 2. This will continue until all numbers are used.

The audio signal shows increasing frequencies after every 50 milliseconds: