The Wii U's surround mode always outputs 6 channels, even when the content is stereo. With stereo content, (everything from Nintendo so far, even the system menu) there are only two channels active in the 6 channel stream. When only two channels are present, there is no real-time surround decoding, which I'm sure the Wii U audio chip is capable of, just 2 active, and 4 useless, dead channels. This precludes outboard surround decoding, as the center, surround, and subwoofer channels are already present, yet silent. Nintendo is using LPCM for the audio output, instead of Dolby Digital or DTS, so there are likely no licensed codecs for real-time surround decoding for the console, so the simple solution would be to limit 2 channel content to 2 channel output, even in surround mode. Only then would outboard surround decoding be possible. At this point, the only workaround which allows outboard surround decoding would be to set the audio output to stereo, but then I'd have to frequently change the setting back to surround to enjoy games which support multichannel. This is crushingly inconvenient.
I've been gaming in surround since the SNES, and this issue makes me feel like I'm forced back into the stereo age. I'm a surround sound enthusiast, and this problem is really destroying the Wii U's value for me. I favor Nintendo, but this odd audio output behavior is simply not competitive in 2012. And before anyone even suggests it: YES, my AV receiver is 100% compatible with the signal, (the Wii U is hands-down, the best sounding console in games with multi-channel content) and NO, its not running through the TV first. To sum it up: Please Nintendo, let the number of channels in the content dictate the number of channels output in surround mode, no forced silent channels!
Sincerely,
A loyal customer