Sound Quality - In home Studio why is it not the same as?????

[Wizzard005]

Aloha All,

So I have a Home Studio, I do listen and pay for Spotify and have for years. Anyways, My question is this, why is the sound quality not the same as itunes, or GrooveMP3 or Pandora HQ streaming?

I have Mackie Studio Monitors with a Apogee Audio Interface.

If i play lets say the Weeknd in itunes, it sounds correct, if i play the same thing on spotify on HQ settins, it sounds muffled?

What gives?   Is there some kind of fix for this?  Muffled music streaming on the desktop and in the car via bluetooth, again, switching to pandora or itunes, it sounds more correct....