Hear Dolby Digital decoding on G5s with Logitech Z680

Oct 21, '03 10:12:00AM

Contributed by: Anonymous

When I ordered my G5 several months ago, I also included the Logitech Z680 surround sound speaker system. The system has an optical input and the G5 has an optical output so I figured it was a good match.

For those of you unfamiliar with the Z680 system, it has a built-in Dobly Digital 5.1 surround decoder. So if you feed it the proper encoded signal, it will decode it and provide true Dolby 5.1 surround sound. They also have standard analog inputs as well. Only the optical interface, however, can carry a Dolby Digital encoded signal. If you use the analog input, the system uses a synthesised 'faux' surround scheme called Dolby Pro Logic, which takes a non surround signal and makes best guesses as to which speakers to send the sound. But this generally is not very good.

Anyway, when I finally got everything hooked up optically -- you need to buy the optical cable as it is not included in the Z680 or G5 box -- I launched DVD player (v3.3) and waited for the beautiful true Dolby Digital 5.1 surround. It never happened. The system -- which has an LCD status display -- would only enter into the simulated Pro Logic mode. This meant it wasn't getting the properly encoded signal. I checked the Sound System Preferences to make sure the output was set to 'Optical digital-out,' which it was, but still no luck.

I was about to resign with the notion that this feature was only going to come with Panther, as I had read some things about true S/PDIF support in Panther, when I discovered in the DVD Player preferences, under the Disc tab, a pop-down list labeled 'Sound Type.' Popping this list down, I was presented with two choices 'System Sound Output' which was the currently selected choice, or 'Digital Out - Built in Audio.' I selected the latter, started playing my Vanilla Sky DVD and, voila!, the speaker status display jumped to Dolby Digital and I was indeed getting true Dolby Digital 5.1 surround!

I hope this is helpful to people. I checked around and I didn't see a similar hint. Also, while searching it seems like a large number of people don't believe true Dolby Digital is supported in pre-Panther systems, so I figured it was worthwhile.

Comments (8)


Mac OS X Hints
http://hints.macworld.com/article.php?story=20031018102230995