This script offers 3 ways to insert tremolos into a MIDI Stream:

1. On a PAD touch
2. When Notes are held down on the controller.
3. Constant (on all notes)

There’s a Youtube video demo’ing the script in an AUM session:

This script was requested and designed with the input of @sujoybose77 to assist in playing a Santoor plug-in.

I like it on:

Hammer Dulcimer (Thumbjam)
Zither from PianoBook.co.uk for the IOS DecentSampler app – both sampleset and DecentSample are free.