Summary: For the record: I am NOT an AKG basher. I own and love the AKG K340. I owned K270 Studios for a while, and liked those. I liked the K701 fairly well, but sold them after a while. I definitely like the K340 best of all the AKG's I have owned.
The AKG's I liked the least, by FAR, however, were the K-601.
Summary: Even though I have several cans that do many things better than the K601, I still found this to be my go-to headphone for some laid back listening before and after work. AKG engineered a winner in regards to comfort and engaging mid-fi sound reproduction that just does not get fatiguing.
This headphone is all about the mids! Not particularly detailed and therefore fairly forgiving, but very involving and musical.
Pros: Extremely comfortable (near weightless), excellent mid range and large soundstage
Cons: Build quality is a little bit flimsy, bass is light and sound is a little lean.
Summary: I'm going to dive straight into the sound of the K601. Bass is where this headphone will be criticized most. Whilst it extends fairly well, the impact can be put to question; when a recording gives you bass impact, the K601 usually comes out with it, but it can fall short sometimes, especially when a recording has been a little reserved in terms of bass. It certainly won't suit the "bass head" type of listener.
Pros: Great comfort, and good sound for the price.
Cons: Design may not fit wider heads, and build quality could be better.
Summary: These were considered the second rate headphones just below the K701 when they first came out, and were priced considerably lower. I considered my pair almost a gift back in 2007. But the K701 got all the attention in the audiophile reviews. Well, little sister has grown up and she is strutting her stuff. Lately, I have noticed that many shops are selling the K601 at the same or higher price relative to the K701.
Pros: seems custom made for the HEARO 999 headamp, a classic AKG sound in an open design, brings beat based music to life, performance beyond price
Cons: needs more amp than price suggests, very loud music listening is likely if properly amped, you might miss some sleep at the least
Summary: I auditioned a variety of headphones, Grado, Sennheiser, the AKG 701, etc. I picked these because they sounded the best to me of the 'phones in this price range. The Grado 225 sounded good, but it was uncomfortable for me. The 701 sounded slightly better, but not worth the additional cost because I don't have a high-end headphone amp. The Sennheiser HD595 was a little bright sounding to me.
I wear headphones a lot, and I like the easy, comfortable listening these offer.
Summary: These headphones are well padded on the actual earcups. The padded velour covers fit on the ears and are very comfortable. Ocassionally, the unpadded leather headstrap felt a little uncomfortable, but you could adjust the heighth slightly to correct this problem. The sound is full and rich, but seemingly neutral. The bass is there, but it is not overpowering.
Summary: I use them as a reference check for mixing / mastering. They are light weight and comfortable and provide a clear and natural representation of the material I am working with. I would recommend them to anyone in pro audio. However, they require a good headphone amplifier and are not well suited for the low output of computers and other hand held devices.