I have the same problem, just realized it tonight. I have the G53jw-a1 and tonight I plugged my computer into my sound system only to realize that it sounds awful. I tried to fix it with the realtek software, but it didn't hep at all.
I saw on another forum that another guy had the same problem and he uninstalled the realtek audio drivers and that fixed the problem for him. I uninstalled the entire realtek audio program, and now I can't use my speakers or microphone, but when I plug in the headphone jack, the sound is much better than it was previously, so I dont really know what to do now other than reinstall the software and try something else.