Hmmmm There s lots of relevant material there but the logical connections are missing You seem to be disputing two claims I have made one that the acoustics are fairly simple and the other that the Yepes Ramirez relationship was collaboration Yes you do make the acoustics sound complicated above but your explanation and mine do not differ in any testable sense so they are the same and IMO mine is better worded That s the reason it sounds so much simpler The quote from Snitzler is very interesting in that it differs somewhat from Ramirez version but both are consistent with regarding it as a collaboration between Ramirez and Yepes Collaboration can mean many things By both accounts this was a long complex personal and creative relationship of which each account is a mere snippet Untangling them is interesting but WP OR and Wikipedia is not the place for it Post your thoughts on it to your own website by all means and I ll look forward to reading it there