Pro logic IIx and my HDTV?

Question

I am trying to hook up my HDTV with an optical cable to my Onkyo 6.1 HT-R520 receiver. I am getting sound, but it is not in surround sound. Apparently Pro Logic IIx is supposed to convert 2 channel stereo into 6.1 or 7.1 surround sound, which I am not hearing. I am wondering if this is happening because I am directly hooking up my HDTV to my receiver, or because my Direct tv receiver doesn't receive Dolby surround. Any answers would be helpful. Thanks in advance.

Answer 1

When you connect a device to a receiver selects the best signal automatically (digital over analog) and if you leave it on Dolby Surround it will switch to Dolby Digital when it detects a Dolby Digital signal. Dolby Digital isn't always 5.1. Sometimes it is 2.0 (meaning that the digital signal is recorded for stereo only) Because the receiver automatically switches to Dolby Digital it will only play the sound out of the Left and Right speakers in this case ( In Dolby Digital the receiver wont change anything, it will only output the sounds out of the speakers it is told to by the material). If you want to make the receiver spread the sound out from a digital 2.0 material your receiver needs an enhanced mode or some version of it. Look for a setting 1 dial click or button away from Dolby Surround or Standard setting. This should get you closer to what you want. It will work for analog sources too but may not be needed for those.

Answer 2

Dolby Pro Logic IIx can "up" a signal to 6.1 channel Movie/Music/Game mode if - the source is PCM (pulse code modulation, like a cd - uncompressed  44.1kHz); analog; Dolby Digital 2/0 (stereo); and DTS 2/0 (stereo) when the surround back setting is set to none (pg.48).

Provides Pro Logic IIx Music/Game mode (no Movie mode) if the surround back setting is NOT set to none (pg.48).

And Pro Logic IIx Music mode only if the surround back setting is NOT set to none AND the Dolby Digital/DTS setting (pg.42) is set to ON.

No Pro Logic IIx modes if PCM signal is 96kHz.

In essence the feature really works best with either stereo PCM or stereo Dolby Digital and DTS signals - which are bitstream by the way (compressed). Also to get the most out of the Pro Logic IIx "up conversion" you need to select NO rear channel in the settings menu or your receiver (pg.48).

They sure didn't make it easy to just sit back and watch a movie in surround - did they?

Hope that helps some.

EDIT:

I forgot to add that only some of the programing from DirecTV is broadcast with Dolby Digital and you need to check the program INFO to see if it is or isn't. There web site had little more than that to say.

from the DirecTV site:

**Surround Sound audio equipment required and sold separately. Not all TV programs are broadcast using Dolby® Digital 5.1 for DIRECTV® programming. Check your on–screen guide in the program description for details.