Foo - Possible to modify monitor?

I want to connect an xbox 360 to my computer monitor via HDMI. If I connect my monitor via HDMI, the monitor produces picture and sound. Great, except I want to use my headphones for sound instead of the terrible integrated speakers. Clearly my monitor has a DAC inside, but I don't see any easy way to bypass the speakers by simply plugging in my headphones into a convenient jack.

Would it be possible to disconnect the speakers internally and solder the wires leading to the speakers to a female 3.5mm jack? What would possible downsides to this be?

The amount of power driving the speakers is going to be more than you want going into a headphone jack.

I've never seen an xbox before. Would it be possible to simply turn off the volume on the computer speakers and get the sound directly from the xbox?

Good point about the power driving the speakers. I wont do this mod.

Its still possible, trace back from the speakers and there will be an amp trace it out and you should find a line level input for it, there is where you want to tap off for headphones.

Nice response. The speakers are a whopping 1.5W each :p. Still, my headphones are supposed to have a max input of 500mW. I'm not particularly savvy with the vernacular of the audio world -- is "line level" a much lower power signal (hence being before the amp)? Will the level be so low that I wont be able to sufficiently drive headphones from it?

If you have ever seen electronic equipment with line in or line out, thats what your getting before the amp. Thats typically where find headphone jacks,they simply have a switch in the jack which switches the signal from going into the amplifier to out the jack. In the older days an analog volume control would be there too.

I always wondered what line out really meant, thanks. I guess I'll do some probing inside my monitor after all. I'm trying to keep this as simple as possible, so if I go through with my plan, I'll simply disconnect the amplifier all together; losing my speakers wont bother me any.

Line level is basically a 1V p-p signal so anything with a line in our out can be designed with that level. Headphone levels are usually about the same.

Look up "impedance matching". This used to be an important topic back in the analogue electronics days. Very simple to do what you want.

Even easier, why not just leave the volume down on the monitor and plug your headphones into the Xbox using one of these adapters?
http://www.cablewholesale.com/prodimages/2rca-female-3.5mm-stereo-female-adapter.jpg (http://www.cablewholesale.com/specs/35mm-to-rca/30s1-01400.htm)

Or one of these (http://www.cablewholesale.com/specs/35mm-to-rca/30s1-01260.htm) depending upon the type of adapter cable you have for the Xbox.
http://www.cablewholesale.com/prodimages/2rca-male-3.5mm-stereo-female-y-cable.jpg (http://www.cablewholesale.com/specs/35mm-to-rca/30s1-01260.htm)