Not sure you gave a price.. The most flat/neutral headphone I heard are the Original NAGRA DT48S 5ohm..They are pretty scarce, so a used DT48e 8ohm makes a good alternative. They can be had used for 125-300.. Very durable.. No glue or plastic anywhere in the design.. The diaphram & magnet are not glued or stuck together, but are separated with their own enclosure. All steel construction with nuts & bolts. These are serious, professional grade monitoring headphones.. If you want emphasis of the highs, treble, bass, then they probably are not for you.. Very plain jane non, fatiguing sound. Very mid range centric IMO, but not forward sounding or offensive..
The 240DF is also a good choice.. CD900ST... 7605, which has been in production for over 20 yrs.. 2nd, only to the DT48 I believe.
This is what some say about the DT48
their medium and high-frequency precision and fidelity remain unparalleled, so much so that some mixers, and not the least, won't use any other models, because their judgment is based on this sound quality.
DCAudiovisuel.com
The truly transparent headphones I've listened to are the HD-800, K-1000, HP-1000, Omega II Mk. 1, DT48, and the K-240DF. That's why I bought them and they won't leave my collection.
Uncle Erik
As for comparison to the K-1000, the DT48 has a similar neutral timbre and excellent range. The DT48 is faster, more transparent and more resolving to me. I can pick out details I haven't noticed before.
Uncle Erik