I recently got a used 2010 Infiniti G37x with the Bose sound system and noticed that the tweeters have a slight crackling sound when playing most songs. I assumed they were blown so I replaced both tweeters with brand new OEM replacement parts from a dealer and they STILL sound like crap...
Just to clarify, I'm referring to the super tiny speakers up next to the windows:
The crackling is subtle enough that they don't really sound blown, they just add sort of a static sound, similar to the sound of digital clipping. It makes the music sound degraded in quality. It's just annoying enough to drive you nuts when you show a friend and they say "It sounds fine to me"...
The crackling is coming from both tweeters, driver and passenger side. It's highly unlikely that both of the new tweeters I just bought are blown. I also ruled out the possibility that the Bose system might just have crappy tweeters in general because my dad has a 2013 G37x with the exact same sound system and his sounds crystal clear.
I'm not the most experienced with car audio so I'm not sure what to check next. What else could cause this problem? Are there any simple tests I can do to help pinpoint the exact cause?