OK, I took a quick read through the manual for your product. First, be sure that your speakers are plugged into the output on the Omega, and not the PC's soundcard output jack. If you have that done, I believe that your solution comes from one of these two sources, which are on the front panel of your Omega.
Monitor Mix Control-
The Omega gives you the ability to
monitor your analog input signals while
recording without the delay incurred by
A/D/A converters and computer
recording latency.This zero-latency
analog monitoring is controlled by the
Monitor Mix knob,which you can use to
blend and adjust the ratio between
OMEGA analog inputs and computer
audio playback.Any signal coming in
on the S/PDIF input is converted to
analog and sent to the mix control so
that you can monitor this input directly
just like an analog input.To listen to just
the source input signal,turn the Mix
knob fully left to Direct.The Output
from the Mix control is routed directly to
the Line and Headphone outputs.This
ability to blend and control the relative
levels of computer audio playback and
latency-free live analog inputs is
effective when overdubbing.
communicating with your computer.
Monitor Assign-
These buttons select whether analog
audio sources are heard in stereo or
mono.Audio sources plugged into the
Omega are placed accordingly in the
analog stereo field.Odd numbered
inputs are routed to the left channel
and even numbered inputs are routed
to the right channel.
Hope that helps some, try it and see.
H2H