Adding some analysis to the discussion of whether Beyoncé sang live when she performed the national anthem at Monday's presidential inauguration, British audio engineer Ian Shepherd has listened carefully to the recordings and come to the conclusion that she was singing live and there was a pre-recorded track of her voice also playing.

In a post on his blog, Shepherd writes that "you can ... clearly hear the pre-recorded backing" in this video posted by the Wall Street Journal Digital Network (a video called to Shepherd's attention by the Apoplectic Skeptic blog).

Shepherd sees other clues, including:

— At one point, Beyoncé "tilts her head slightly and the sound gets suddenly more bassy. This is an acoustic effect known as the 'proximity effect.' "

— Removing her earpiece, as the singer did, would let her "hear her own voice more clearly and sing in tune more easily. (In fact, if the pre-recorded vocal was going to her earpiece, she may well have been finding it distracting.)"

— "At [2 minutes, 17 seconds] she smiles slightly, and you can hear this 'smile' in her voice."

Beyoncé has yet to comment on this important/not important (you decide which it is) story. We suspect we haven't heard the last word on all this.