Bluegrass Underground, the new live performance radio show we posted about last month, debuts tonight (8/29) on WSM. The show features a live performance by The Steeldrivers, recorded August 16 more than 300 feet underground at Cumberland Caverns in McMinnville, TN.

The show’s premise is based around the unique environment where it is recorded, this underground cavern completely removed from any sound generated at the earth’s surface. Each month, a new episode will be taped before a live audience, using as few microphones as possible to capture the natural acoustic sound, and aired on the last Friday night of the month.

Producer Todd Mayo told us that this first concert taping was a sellout, and that The Steeldrivers put on a whale of a show. He also sent along some photos that demonstrate the dramatic surroundings where they record.

Here’s a video clip that gives an even better look at the concert hall.