Katie Couric began tonight's Evening News with, "Good evening, everyone. And welcome to our first broadcast in high definition." Unfortunately some viewers around the country watching in HD only saw Couric, they couldn't hear her. While the audio problems were not noticed in most markets, including New York, Chicago, Philadelphia, Dallas, Boston, Denver and Atlanta; Washington, DC's WUSA, did experience the problem. There was no audio for the first 20 seconds of the broadcast. Then, according to the blog DCRTV, "they flipped back to old standard-def version. The HD was re-instated, with audio, about halfway into the newscast."

It was most likely an error on CBS's end, but many stations were able to switch to the standard feed quickly enough that it was not noticed at home. Eight minutes into the east coast feed, at approximately 6:38, the HD feed was restored.

But by then, many people who had tuned in to see Couric in HD, had already been emailing TVNewser.

• 6:33 CBS is no longer broadcasting in HD in the Nashville market.

• The sound was out for half the show on my affiliate in Chattanooga. Looked good, but couldn't hear a damn thing.

• I'm watching Katie's debut in HD. The picture is beautiful, but from 6:30-6:38, there was no audio. Then they switched to the SD feed which had audio. Then back to HD at 6:39 without audio, and right back to the SD feed with audio. I'm watching on WPRI-HD 12 vi Verizon FiOS in Providence, RI

We're still trying to determine the source of the audio problem. When we learn more from CBS, we'll pass it on to you.