I have set the Marimba voice into R1 and the Steel Drums to R2 just for demonstration.
![Image](https://i.imgur.com/LzPTkZ4.jpg)
Now press "Direct Access" button and then the Harmony/Echo buton to get this screen.
Scroll down to "Tremolo". I set mijn to 16 for the tremolo as it sounds OK to me.
Use the same settings for both drums and Marimba.
![Image](https://i.imgur.com/2NNUQUG.jpg)
Now press Registration Memory button and make sure that the Harmony box is ticked.
![Image](https://i.imgur.com/nAl79lR.jpg)
Go to Functions and pick Registration Sequence, tab to Freeze and tick the harmony box.
![Image](https://i.imgur.com/Pk6QlKkl.jpg)
All set for the tremolo sounds. The Harmony/Echo button must be ON for the effect.
Den