Borrowed this CD from the public library at Singapore's Esplanade Theatres By The Bay. It sounded like the player had probably used silk strings.
You can find this CD inside this drawer in the Esplanade library (highlighted in red rectangle in the picture below).
You can also hear the contents of this CD online at http://www.xiami.com/album/461878?spm=a1z1s.3521865.23309997.3.s3Uehj
It's great to find audio recordings of guqin tunes that might have used silk strings. They sound more mellow and without any metallic buzz. haha *smile*