This was sung by a small choir at the famous Valaam Podvorie in Moscow 4 years ago.
Typical Valaam chant starts at around 31:00 minutes for those familiar with Valaam's magnificent chants.
This is the same choir conductor, Hierodeacon Herman [ German in Russian ] who produced this fabulous recording of Agni Parthene in 1998 :
http://euphrosynoscafe.com/forum/viewto ... 12&t=11903