Alright, so I just listened to a really rough mix in my car of a song I've been working on for a few days, and I noticed that the cymbals in the song, almost all the highs actually, were really shrill almost to the point of being unlistenable. The whole song is also rather thin sounding. This is contrary to how everything was sounding coming out of my monitors. Is this something that I'll be able to adjust in the mastering process? I know very little about it, so any advice would be helpful.