I purchased this pair about 2 years ago, when I just got to the audiophile world. I remember reading a thread the ATH-M50 and HFI-580 with a lot of different opinions, so I decided to test both. The local shop provide me 2 sample of the headphones, both had experience hundreds of hours of playing music. So this is more like a comparison:
Bass is very detailed and well tuned, doesn't overpower. It just stay there and when the song calls for it, you'll be surprised how tight and controlled the bass is. This is the bass quality of decent 300$ plus headphones. If the M50's bass is all about quantity, while 580 is quality.
The mids and the high is just above average; might be better than the M50 a little due to its wide soundstage
This is the best pair you can get for under 200$, however, if you want bass quantity, go for the M50, it's a great choice too.