So, I have been listening to music with my KRK-KNS 6400's and so far I have really enjoyed the quality. The thing is, I have been primarily using Spotify. Is there a higher quality place to get music? I know there are different formats and such, but I really don't know what to make of them. Help...

Hello,   I am new to Hi-Fi audio and I am really wanting to get in to it. I recently purchased a pair of KRK-KNS 6400 and I really loved them. I am wondering were I should go next with my Hi-Fi journey, so to speak. I am really interested in the Grado SR-80i's and the Seinheisser Momentums...