Recommended acoustic recordings

Any record featuring Eva Cassidy
Joan Baez "In Concert"

Sufjan Stevens "Seven Swans"

Not SACD but a pretty decent recording and one of my favorite albums of all time.

Jack Rose "Black Dirt Sessions"
Oliver Jones "Cookin' At the Sweet Basil"
Anat Cohen "Clarinet Work: Live At the Village Vanguard"

Second Eva Cassidy, especially the Songbird album on vinyl.

Opus 3 - Thorvald Fredin, "Concertos for Double Bass & Orchestra" SACD 8522 - classical music for orchestra and double bass by Bottesini, Erland von Koch and Lars-Erik Larsson. The Larsson piece is particularly fine.
http://www.opus3records.com/class_orch.html#8522

If you don't know the recordings on the Opus 3 label, I encourage you to explore them. They are all acoustic and exceptionally well recorded with emphasis on getting a capturing the timbre of instruments and reproducing the original performance space as naturally as possible.