The sound spectrum isn't really there. Many have commented that they are disappointed in the 19 speaker Harmon Kardon system. I will agree that it sounds flat and not full spectrum. My old Bose system in my 2006 Silverado sounded so much better.
However, in Orlando, there's a rock station that plays in HD, and when the HD kicks in, the audio is phenomenal. Listening to the same station without HD sounds flat, as does SiriusXM and other non-HD radio stations. I find the HD sound and the streaming (Pandora or Spotify) from my phone sound the best.
I may need to replace the speakers with better sounding ones, but it hasn't been a priority since I listen to the same station, that sounds great when HD is active.