Lunasa treads a fine line between the strictly traditional approach to Irish music taken by bands like Altan or Cherish the Ladies and the somewhat more progressive approach used by groups like Solas and Deante.
Although the group's instrumental lineup (flute, fiddle, guitar, and bass) is pretty well within the bounds of tradition, their approach to recording is not: on a reel set consisting of "The Butlers of Glen Avenue," "Sliabh Russell," and "Cathal McConnell's," flutist Kevin Crawford is double-tracked on flute and whistle and plays in harmony with guest artist Mike McGoldrick himself double-tracked on union pipes and low whistle.
This setting is typical for Lunasa (repeated with guest piper John McSherry on the air "January Snows" and Phil Cunningham's Laura Lynn Cunningham," for example) and it yields a sound that is unique to the group and yet clearly in touch with tradition.
Most importantly, it's a very attractive sound, rich and dense but still danceable. Less traditional are the occasional incursions of electric bass, cello, and (believe it or not) flügelhorn.
But it's hard to imagine any but the most uptight folkies objecting to the final product.