Check out a rare carbon fiber (FRONT AND BACK) autoharp on the market. It has a loud, detailed sound with great sustain. It holds it's tune incredibly well, and can handle temperature fluctuations and humidity better (better, but not impervious to weather and humidity extremes) than an all wood instrument. It will hold it's tune in conditions an all wood instrument cannot.
Hal Weeks Comparing a Spruce Cascade with a Freedom Autoharp:
https://www.youtube.com/watch?v=48jchCB7a1M&t=13s
Serial Number: 8151012CF