i drive an 05 scion tC. it has the stock pioneer cd deck in it, stock front speakers and tweeters. i changed out the rears for some fusion components and added a sub. when i first got the car, i could listen to cds on a volume of 25 and it was reasonable. now, i have to put it on at least 30 to sound similar. i know my hearing isn't going, i keep very good care of my eardrums. do you think that the cd deck or speakers just aren't as efficient as when i first got the car?