So, I was rooting around the interwebs for some history of the electric bass.
I came up on the back story of the Tutmarc 736 bass fiddle.
Here is a YT video demonstrating this amazing instrument. The video itself is pretty low quality, but if you FF to 5:38 you get a sample of the sound.
and here is a bit of history
https://www.youtube.com/watch?v=ZF3frR_hdII
and an article