tapewound is just another name for flatwound. All electric guitar strings were flatwound until Rotosound introduced roundwounds in '58 - even then they didn't catch on with most players until the late '60s.
The nylon flatwounds are an attempt to make an electric bass guitar sound more like an acoustic upright bass (also a Rotosound innovation IINM). Funny - I didn't think they were around until the early '80s, but in the Yardbirds clip it does look and sound like them...
Reinhard wrote:
this is pretty cool bass tone too
Free's Andy Fraser always sounded great - humbucker basses + valve amps = gorgeous fat crunchy tones. He had a big influence on Billy Sheehan (alongside Chris Squire of Yes).