Suddenly, as of a few days ago, I am unable to get Dolby Digital audio from my Scientific Atlanta cable box.

There are two hook-ups as follows:

1)cable box to TV: HDMI
2)cable box to Pre/Pro: optical

One of two settings used at any given time with cable box:

1) Audio Out = HDMI
2) Audio Out = Dolby Digital

It is with setting #2 (Audio Out = Dolby Digital) that I no longer get any sound. None of the speaker icons on my pre/pro light up whereas before they did when working properly.

When "Audio Out" is set to HDMI I do get sound but it is PLIIx and not DD.

My Pre/Pro is a Boston Acoustic AVP7 which is a clone of the Sherwood Newcastle P-965.

Any ideas why this suddenly stopped working?

I'm not sure what is causing it, but I have had a similar issue before with Dolby Digital output from my Scientific Atlanta cable box. On probably two occasions I've found that the cable box quits providing digital audio output when set to DD. Instead, it only works when set to PCM. A few days later, turning Dolby Digital back on would work fine. Since your HDTV's EDID probably tells the cable box that it wants PCM rather than Dolby Digital, it probably is causing the cable box to decode everything to PCM when the digital output is set to HDMI.

Sounds like nothing is "broke" per se - good to know. I do prefer DD audio over PCM with TV, but since it is only with television audio that this occurs it's not a big problem.

On a different topic, I setup my new Oppo BDP-83SE using your settings guide. Thanks for providing that Gonk, it was very helpful.

If I had to guess, you could probably switch back to Dolby Digital in a day or so and get back to normal. If it still doesn't work, I'd call your cable provider - even though I personally can't stand pursuing any sort of technical questions with cable TV customer support.

Had a thought to unplug and restart my cable box. DD now works. Go figure.