I have noticed that since performing the upgrade on my 990 that it frequently decodes movies played on my cable box in Dolby Digital EX. Prior to the upgrade I cannot recall one instance where the 990 auto selected EX. Has anyone else noticed this new behavior?

I still haven't done the firmware update, but I can offer a theory... The 990 remembers user-selected preferences for decoding and processing, but when you did the firmware update you reset the unit and all those remembered preferences were wiped out. That's likely why you are seeing different behavior.

Perhaps I'm mistaken, but it seems to me that prior to the upgrade, while scrolling through the surround modes,Dolby Digital EX was not even available as an option on most program sources. Obviously I'm not complaining but rather making an observation.

I've also updated the firmware and I've noticed a perhaps related behavior. When watching Comcast OnDemand HD music videos, even though I have the 990 set at Dolby Digital, when a new video starts, it will switch to PL II Movie -, which is not a good match for music. I then manually switch back to Dolby Digital.

I've looked in the Video1 setup and it had surround mode set to SV Wide.

Is there something in the HD video content that causes the 990 to detect something and switch modes?

I'm running without a center channel because my mains produce a very strong phantom center. Is it possible that having center=off with the 990 is affecting the mode detection/switching behavior?

Dolby EX will only be an option if you have surround back speakers enabled. Even when you do have surround back speaker(s), EX can only be used with a Dolby 5.1 source - something that you're only going to get from a DVD or some HD broadcasts.

Those stations are probably broadcasting in Dolby 2.0 (the same as many of the digital cable channels) so if you've selected PLII-Movie for TV shows it will treat the music stations in the same way. You'll end up having to toggle surround mode back and forth.

There is a work-around, one that I've used for a long time with CD's played from a DVD player. If you assign the same digital audio input to both Video 1 and Aux, you can set the Aux input to use Dolby Digital for Dolby 2.0 sources - then you just need to switch from Video 1 to Aux when listening to music. Since Aux is an audio-only input, the video switching will stay with the Video 1 input.

Edit: One other thing that I forgot to mention. The setup menu screen that shows surround mode is dependent on the current input signal. To really see what is happening in this regard, it's best to have the input in question active and playing a source that you are interested in.
I don't know of any reason for this to be the case.

Gonk, can you elaborate on what you mean by this?

Thanks,
-Mark

Most of the channels are going to be using Dolby Digital 2.0, so if you use Pro Logic II with those, you will also get it with the music channels (in the 990's mind, they are the exact same thing). Change to Dolby Digital for the music channels so you are in straight stereo, and you'll end up with straight stereo on TV shows too.

Gonk, what has me confused is that I never select Pro Logic II. I always set Dolby Digital. In the course of navigating different content on the cable box, the 990 switches to Pro Logic II on its own.