Are you using a headset? If for no other reason than battery life, I would be using a headset for any pad, smartphone or whatever I was using...
If that is not the problem, looking at the volume mixer might show if the output is equal to the volume setting.. Left click the speaker icon and check the volume mixer.
Sound output on a netbook is always going to be limited. Any attempt to push it beyond its design limits is likely to result in unacceptable distortion. I use a usb powered external speaker for mine when I require better output - would this be a workable solution for you?