I believe the sound track comes from a recording, made in 1957, but very clear, of the The Benedictine monks of the Saint-Maurice and Saint Maur Abbey, Clervaux, Luxembourg. It is well worth getting a CD of them if you enjoyed this chant. I have enjoyed listening to it for many years now.

See tinyurl.com/6jw7cjv Amazon UK or tinyurl.com/6dos9om Amazon USA