I've been experimenting with gut strings during last year, and here's a mellow jazz piece by Teemu Halmkrona, that I'm playing with my Chzechoslovakian plywood bass from around 50's with Efrano gut strings.

https://soundcloud.com/teemuhalmkrona/myo-ta-tuuleen

Hope You enjoy. I'm falling deeper and deeper into that earthy sound of guts...