What makes a headphone sound good is how comfortable it really is. And the soft foam that makes it comfortable also affects the sound quality in ways you might not of known.
I have modified a 5$ pair of headphones to sound clearer than a 50$ pair of sony headphones
The secret is the foam pads that comfort your ears while wearing your headphones. If you change them for more comfortable and better materials your headphones will definitely sound better than before. Even if the headphones are bad when bought brand new they can easily be made to sound more than 5 times clearer by this simple trick!
All you need is a pair of scissors and various headphone comfort pads to try until you find one that is the most comfortable. and sounds the best!