This is really annoying: Whenever I change digital channels on my TV, the reciever changes the surround mode. Each time I change the channel, the digital audio signal is interupted. Then the digital audio signal is re-established, the reciever detects the new digital audio signal, and the reciever resets the surround mode as follows:
Digital channel to another digital channel: Surround changes from Dolby Digital ProLogic (surround sound) to Dolby Digital (2 speakers only).
Analog channel to a digital channel: Surround changes from PCM ProLogic to Dolby Digital.
Digital channel to an analog channel: Surround changes from Dolby Digital ProLogic to PCM Surround Off.
Analog channel to an analog channel: Works fine, reciever does not reset the surround mode.
I want the reciver to maintain the ProLogic setting whenever the digital audio signal interupted.
My reciever is a JBL DCR600 (JBL Cinema ProPack), which is really just a modified and relabeled Harmon Kardon AVR110 (JBL is a Harmon International Company).
My TV is a new Toshiba 62HMX94.
The Reciever is connected to the TV through an optical audio cable. The TV converts all analog audio to a PCM signal for transmission through the optical cable. It passes through any Dolby Digital signals from digital TV channels.
This is my only experience with digital TV and a surround sound audio reciever. Do other recievers exibit this behavior? Is there a way to fix my reciver to remain on ProLogic?
I have a somewhat similar situation with my setup. I think the critical component is your cable/satellite box. In my case digital channels were either 5.1 DD or 2.0 DD, I couldn't change them to ProLogic with my receiver (NAD T742). The analog channels were all ProLogic. There would be an annoying pause when switching from an analog to a digital channel and a 'click' noise as well.
I changed the output of my satellite receiver to always output PCM from the digital optical output instead of DD for digital channels and PCM otherwise. So, now it's always ProLogic regardless. You may want to try doing a search for your particular cable/satellite box.
The receiver will sense the flag in the signal sending to it via the digital input then enable the appropriate decoder to decode the sound properly. Recent receivers come with multichannel processors such as Dolby Prologic II/IIx, DTS Neo:6, Logic 7, etc. to create 5.1/6.1/7.1 sound from a stereo source. You'll need to enable one of those for stereo source and set the input mode to auto for the receiver to decode the sound in the way you prefer automatically.
Arlin, yea that's how I use my system. I rarely receive any 5.1 broadcasts, but when I do it's usually a movie so I switch the satellite output to DD via the setup menu and switch it back to PCM when the movie's over.
One other thing you could try is to set the digital output to DD only from your TV(if this is an option), and as well connect the RCA L/R outputs to the corresponding input on your receiver (i.e. DD output to SAT digital input and RCA to analog L/R SAT input). Depending on how fast your receiver is at detecting the absense or presence of a digital signal this might work better. You may have an issue though getting the ProLogic setting to 'stick' when you have a DD2.0 signal.