I have a 90 Oldsmobile that I have custom mounted the rear 6x9" speakers. The top of the speakers are on the platform right behind the rear seats and the magnets stick into the trunk so they are actually using the trunk as the enclosure. However I also have 2 10" subs in a custom sealed box in the trunk. I have noticed that when the subs hit low notes or when I turn the subs up really loud, it affects the way the 6x9" speakers move. I want my 6x9's to hit the higher bass notes or me, but when the subs move, it makes the 6x9's move too. I was wanting to know if this is affecting the way the 6x9's are working because technically the subs and 6x9's are in the same encolsure (the trunk.) Is this OK, or is there some way I can resolve this problem if the subs are indeed interfearing with the 6x9's? Like maybe building two little enclosures to go over them? If somebody has any tips for me I would greatly appreciate it if you could let me know. Thank you.