Ok here are your options:
because if your soundcard has 2 outputs, say line out and speakers... then
those 2 change simultainiously and cannot
be conntroled seperatly using software...
unless... your sound card is one of the new ones that has many outputs for a
home sound system with 5 speakers...
These have 3 output jacks, one for 2 front, one for 2 back and one for
subwoofer speakers.
If this is the case theoretically you can use software to isolate the sound
in the 2 front channels (speakers) or earphones (2 back channels). However I
never had such a card.. so I cant give you details...
another solution:
If you have 2 simple sound cards or usb earphones you can use a small
program to switch between the 2.
(when I say 2 sound cards, one could be the built in one from your
motherboard - if it has one)
This is the program you can switch between sound cards, or soundcard and usb
earphones:
http://www.winsite.com/bin/Info?19000000037599
hope this information helps