Pros: Probably one of the best midrange in the world, great for their price
Cons: Not enough extension on both ends
This is my first non-thread review. I gambled on the AKG K501 and fell in love with it. It is considered by many as one of the best headphones AKG ever produced, apart from the polarizing K1000. It is well known for a very natural and realistic tone or timbre which is something I'm very fussy about. IMO, the K501 nails timbre allowing music to sound almost as good as the real thing. The midrange is simply beautiful. It is slightly thick and lush while maintaining all detail. I wouldn't consider it bass light, my AD900 has less bass. I think the K501 is almost perfectly balanced.
However, it is not without it's own flaws. Compared to modern headphones like the AD900 and FA-003, it has less overall detail and extension on both ends. But it has the soul of a true classic headphone. One that focuses on producing beautiful mids instead of trying too hard to nail the frequency response. Just as another reviewer said before me, this is one headphones that every audiophile should have in their collection, especially at the price they can be had. I repeat, you probably won't get much better midrange than this unless you're willing to spend a lot more.