exhaust note

I noticed an exhaust reverberation or drone in the car in 2nd/3rd gear under moderate throttle....it's heavy enough to make the parcel shelf rattle (car has 90 miles on it) much louder and annoying than the exhaust note on my good friend's '16 windows open or closed it's pretty bad....has...

So i had kind of a funny thing occur- me and my mom were watching videos of me pulling switchblades (180's)and she chimed in and said that was cool, but that my exhaust sound didnt fit my vehicle very well (she felt there was too much treble with full throttle). I had stock exhaust and i thought...