Huge change in audio quality simply by changing the pads on headphones?

so i bought a cheap pair of 5$ sentry headphones from big lots and they sounded terrible to begin with one channel was wired out of phase with the other so i had to open the headphones up and re solder the headphone leads on one of the headphones.
Once I fixed that they still sounded boring with far too much mids and bad harsh treble and little to no bass.
Simply taking the little foam pads off and swapping them for a home-made pair of pads that go all the way around your ears in a noise cancelling design the treble was increased to a crisp clean sparkling treble the boomy mids were reduced and the low frequency bass was increased.
The overall sound quality went from 99 cent headphones to 50$ headphones and they are very comfortable this way i could wear them for hours on end compared to before. if I had a camera I would take some photos to show you what i'm working with. the drivers are 30mm 16 ohms 20hz-20khz but they sound far better than even my logitech headset they have very detailed high frequencies.

Just by swapping the stock pads for custom ones that I made myself. Who would of thought?
My friend said they sounded better than his headphones that costed him over 35$

could there be another reason why just swapping the headphone pads out would make such a drastic change in sound quality?