Also to know is, are 50mm drivers good?
Well a 50mm driver is larger and more powerful giving it better sound quality.
Similarly, what is a good driver size for headphones? Driver Diameter – Headphone sound quality depends to a great extent on the size of the diaphragm, which is indicated by the driver diameter: the larger the diameter, the better the sound quality tends to be. Most drivers for earbuds are 13.5–15.4 mm in diameter, with those for canalphones being 8.8–12.5 mm.
In this way, what's better 40mm or 50mm drivers?
a good quality 40mm can beat 50mm. Sound is very subjective, you should test them both before buying. in theory bigger speaker can generate "bigger" sound, becasue they can vibrate air molecules more than smaller ones.
What does mm driver mean?
The driver unit is made up of magnets, voice coils and a cone-like diaphragm (measured in mm) and is one of the most essential pieces of the headphone. Its job is to convert the electrical signal into a sound wave that the ear can understand.