The problem is, that I think the game needs hardware DirectSound support to be able to do 3D audio or that it needs EAX > 2.0.
But the most sound adapters (onboard) just dont have hardware acceleration, they do nearly everything in software via a driver (by using the CPU). Also they usually stuck at EAX 2.0. The only exception are Creative Soundcards, but I really doubt, that you have such a card, because you usually have to buy a separate card.
Another problem is, that Microsoft removed hardware accelerated DirectSound since Windows Vista (Windows 8 does support it again). So, all games that rely on it, wont be able to use it (not just Sacred)!
In case you really own a Creative Soundcard, there is a solution, that is called Alchemy. It is as far as I understand a wrapper, that enables hardware DirectSound (even on Windows Vista and 7) by translating all commands into OpenAL, which supports hardware accelerated 3D sound.
Because I have such a Creative Soundcard and use Alchemy I can turn this on, even on Windows 7, but for most others this just wont work (not just in Sacred).