i heard about dpl2 on the gamecube. i assumed it was some crappy pseudo-surround thing and never paid attention to it. recently i got around to routing my wii's audio through my receiver. i enabled dpl2 on the input, and fired up zelda. sure enough, there was sound coming out of the rear speakers but nothing was really channel-specific in the intro movie. i wanted to test it properly without having to take heroic measures in-game to isolate sounds.
so i did a little research, and it turns out that
star wars rogue squadron ii: rogue leader for the gamecube has a dpl2 audio test. i picked up a copy for $10 on my way home from work, figuring i'd at least get $5 worth of test and $5 worth of game. the test has a tie fighter circling around, moving from speaker to speaker. i was shocked at how well it worked. it wasn't just piping the same stuff through my 5.1 speaker setup, it had fully isolated channels! i
read about dpl2 on wikipedia and it is some really ingenious stuff. dpl2x can even scale a signal up to 6.1 and 7.1 setups. ign also has a
good interview with the rogue leader developers about it.
i was shocked to discover as i was typing this post that it was actually a launch title for the gamecube. wtf?! some of the best graphics i've seen on the gamecube, progressive scan support, fantastic score, and surround sound all in addition to totally solid and fun gameplay. i don't know how i managed to not hear great things about this game or dpl2 right after the gamecube was released.
cliff notes: dpl2 surround rocks. if your receiver supports it, use it. you don't need special cables. you can test it really well with rogue leader, an excellent gamecube game.