Wow that's great Sedayne. I put Blondel into YouTube a while ago and all I got was Swifts and Swains and some rural stills. This clip of Cantus Firmus was lovely so thanks for that. indeed I remember this coming out as a single back in 1974ish and was amazed to hear it one evening whilst watching Coronation Street. It was coming out of Elsie' Tanner's radio or somthing. In fact I'm on Coronation Street in a week or two; just a walk on but I once had a short speaking part on Hollyoaks. Ah, how are the mighty fallen!
I may be being a bit dim Jack but what do you mean by an ABC of SOY? Do you mean the notes? If so it is played on an alto crumhorn and the first note is an f natural which is all seven fingers down; ie the lowest note on the instrument.

Mike Billington.