The problem doesn't have anything to do with GSX, which doesn't try to interact with your audio card directly.
GSX uses the standard OpenAL library to create sounds so, any problem you might have with sound in GSX, is caused by problems with the OpenGL implementation of your audio card, and there's simply nothing we can do to fix them from our side, since we only do standard OpenAL calls, but if the driver is bugged, is entirely outside our control.
In any case, isn't the Z506 just a set of speakers ? Which audio card they are connected to ?