I have tested Donkey Kong64 with XAudio2 upmix (surround) feature with SRS Audio SandBox, although I don't have a 5.1 sound card, but it works.

If you already have 5.1 sound card or speaker, then you don't need to install SRS Audio Sandbox. Some user has UAC problem to start the service after install srs audio sandbox on windows 8, and causes lag of DirectSound. Take your own risk to install this audio driver.

Here are the steps

(1) Install SRS Audio SandBox 1.10.2.0, then you will have a new sound device




(2) Setup your speaker for SRS Audio Sandbox (WDM) device to 5.1



(3) Run SRS Audio SandBox, turn it on



(4) Enable HleAudio XAudio2 upmix option



(5) Enable Surround for Donkey Kong 64 in game option menu

Donkey Kong Sound Setting

That's it.