Crackling sound issues

I have a question for the community because my experience troubleshooting sound issues is rather limited. I have a problem where my computer sound crackles when I play music. I think it is the motherboard, however, I was wondering if it could possibly be something else because I also get the issue with my mentor 5.1 headphones(I am a noob and dunno if the sound gets processed in the same place for both outputs). I hope someone can confirm my suspicions and if it is the onboard sound then I will just go purchase a low end sound-card to replace. I was just planning on getting something basic like a Creative Sound Blaster Audigy SE 7.1 as a replacement. If there a definite reason that the problem does not stem from the motherboard, or that I should get a different low end card, please let know.