Summary: Here are my brief impressions on the K601. The K601 is that it is rather musical, especially when compared with the DT880 (of which I prefer the K601). I have done some brief listening to both the K501 and K701 (both of which I found great). As a benchmark for comparison, here are my impressions on the K501, K701 and DT880. K501 -> Lean, tight bass (may be considered somewhat deficient). Very wide soundstage. K701 -> Nice across the board. Really black between the notes.
Summary: The K601 was bought to replace a Grado SR60, which replaced my Grado SR200. I got rid of my Grado SR200 headphones as they were not very comfortable. The earpads were unbearble after about an hour, so I bought the SR60 and liked them better overall, but I finally decided to get a better sounding set of cans. The SR200 has less bass extension than the SR60, but the SR60 is not as well controlled and a bit less distinct.
Summary: There's been a lot of debate on the internet forums as to the quality of the AKG K601s, espeically against the K701s given the rather small price differnece. Well, having lived with the K601s for over a year I feel I can comfortably comment on the sonic qualities of the K601s (I'll get to the K701s a bit later when I review them under the K701 heading). First off, the K601s are a fairly well balanced, even sounding, coherent set of open backed headphones.
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. I bought a pair of K601's on some recommendations I had read, however, after several weeks of burn in and then listening, I thought they were just dreadful.
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.
Excerpt: These headphones sound true to the sound as reference headphones should. I use them for picking out noises and unwanted sounds in a mix. They are very comfortable and can be worn for hours. They need a good headphone amp to push but otherwise they are great!!
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