May 2014 - last edited November 2016
Mass Effect lacks surround sound on most hardware, and even if your hardware is supported, it requires tweaking a file to implement it. When applying this tweak, you get the following:
Note that this is only supported on a minority of sound cards. Supported hardware includes some cards in the Creative X-fi and Asus Xonar lineups. It may also work on onboard audio solutions on ASRock and Asus motherboards if you install X-Fi MB, which is premium software.
Don't change any settings in-game, because it may override your ini file. If your hardware is supported, you will have 5.1 surround sound, possibly with environmental audio as well. Note that this can affect performance if your sound card uses software emulated EAX.
Creative Alchemy is NOT required to enable EAX.
I don't work for EA.