The same problem, similar settings.
All games (currently Batman AC, Skyrim, JustCause, Metro2033,...) running with 5.1 sound, Arma II OA do not - only stereo :(
Config: onboard audio ALC898 (Asus P8Z77-V Deluxe), running in DTS-Connect through optical to Logitech Z-5500 repro.
ArmaII OA, retail DVD, Version 1.6 and 1.60.93398 beta
Log:
Error: Audio - enumeration output devices failed.
Warning: Audio device creation failed, attempt to create default audio:
SamplesPerSec: 44100, channels: 2, bitsPerSample: 16
Audio device successfully created with default settings.
Actions taken: read relevant threads here. Sound device is "default" and "communication default" device. HDMI sound devices are all disabled. XAudio2Sound3D gives the same error - no positional effect - stereo only. Latest DirectX installed. Latest Realtek drivers installed.
Interesting thing: if I connect repro through analog cables, problem persists! -openal, -dsound didn't help either.
Thanks for any advice, except "buy dedicated sound card" :)
