I have some closed-back headphones that have poor sound. Is it possible to improve the sound of the headphones by installing additional speakers?
How much better can the sound of the headphones be if the cups are covered with soundproofing tape?
If your headphones are crappy, a better source won’t really help. It’s not an or here, headphones make most of the difference. Only decent headphones will appreciably benefit from a good source.
MP3 isn’t ideal but, unless you have rather good headphones, 320kbit/s MP3 is pretty damn near transparent.
The point is, we don’t know what kind of headphones or what kind of source OP is using.
These are Chinese headphones with no name. However, they looked impressive and I was foolish enough to buy them instead of the inexpensive Sennheiser headphones which cost about the same.