Did Rascal Flatts Lip-Sync at the ACM Awards?

At the ACM awards show last night, I noticed some of the performances seemed a little well, "off!" I just chalked it up to the artists not being able to hear themselves and it was live. But when Rascal Flatts sang their latest hit "Rewind," the rumors began! Right when Rascal Flatts began singing, it sounded like the broadcast audio may have switch to a pre-recorded track. Lead singer Gary LeVox, seemed out of sync, and it seemed to sound better than the other live performances earlier in the show.

Was there a separate audio track being used in over the performance?

In the opening monologue with co-hosts Luke Bryan and Blake Shelton, Shelton was quick to say we would be hearing "live music" tonight. Hear is a quote straight from Blake Shelton:

”If you don’t like live music, then you need to go down the block and see Britney Spears.”

I'm certainly not a professional, but it did seem strange. Now I am a huge fan of Rascal Flatts and those guys have crazy vocals, so I'm not saying they can't sing, I'm just curious about the situation.

This morning on Big D and Bubba, listeners called in to give their opinions, and most of those calls thought the group was lip-syncing.

If you caught the performance, what do you think? Did Rascal Flatts lip sync while all the other performers committed to singing live?