I made a Cello instrument in the D-Synth which is sounding (due to the verb) very natural over 4+ octaves.
Im still pretty new to the OP-1 (2 weeks so far) but i really like it. My background is analog subtractive synthesis and the OP-1 with his unorthodox way of approaching sound design is very new, exciting and overall a very pleasant experience
I was really surprised when I came across the Cello in D-Synth because the first hours with it was just glitchy and aliasing haha
Hope you like it, and if you used it in a track or so then i would really appreciate it if you shared your track here (too)