FYI - Folks over on the AVS forum have verified that the audio problem with the Zenith / Insignia boxes appears to have been remedied in recent production runs dated April 08. For example, locate the sticker on the side of the carton and look for:

84Exxxxx (2008, 4th month)
or a SN# that begins: 804SHYxxxxx (again, 2008, 4th month)

Any unit prior to April will still exhibit the audio glitch.