(heres where the facepalm question starts) If I wanted to play it as a 4 note chord instead, could I also play a lower D? Can I play a lower A with it and have it still be 'Dsus2' ? Obviously D is the root so I'm thinking it would be ok to play another D with it.. I mean it sounds fine but yet it doesn't at the same time.. hmm.
Yes this question may make me seem obtuse but please don't tell me to google.. thats the only reason I found dsus2 in the first place