I have a Tivo 3 that's been fine recording SD PBS shows, and the sound from BR and DVD is also fine. But I've had to delete a bunch of HD PBS shows from the Tivo because the center channel is missing, or almost missing. You hear the music, effects, etc. but barely hear any dialog or narration.

What would you check? Could it be a problem at the station?

(Tivo's getting OTA from a rooftop antenna. It's connected to a Yamaha 3800 via HDMI, and Yamaha is connected to TV via HDMI)

I would suspect a broadcast problem, not a problem with the TiVo. I had this happen with Lost on ABC a couple years ago a few different times, due to known broadcast issues - the entire center channel was just gone for no apparent reason, yielding a complete lack of dialog. I had a to watch a few episodes with closed captioning turned on to know what was going on...

Demonfoo, I think you're right. I re-checked the PBS station's various channels. The SD and other digital channels are fine, only their HD channel has the problem.

I can actually hear the voices, but they sound like they're coming from inside a bank vault.