Frank Berger

The melody strings are violin strings with metal core. The thinnest and the thickest ones. Metal because there are magnetic pickups for the melody strings.
They are both in G in octaves. It is G and E strings. 🙂
The trompette are nylon. They are in C and D. And with a capo on the D one, so it can be switched to E.
Drones are in C and G. Wounded nylon strings. A capo on the G one allows you to switch it to A.