Processing:
Both models seem to be quite well made and are therefore probably also work for a while.
The K 420 but works through its Kunstoffbügel and its improved height adjustment still to some noble.
Comfort:
This point clearly wins the K 420th
Due to its better strap padding and its lower contact pressure he wears a lot more comfortable.
You can wear for hours actually him.
The older K 412 suppressed much earlier due to its small strap padding and the considerably higher pressure.
Sound:
In the most important point, the sound, the two headphones take almost nothing.
Both play very balanced and neutral. Bass, middle and treble come over any time clean, punchy and differentiated.
Perhaps the K 420 sounds a bit full by its minimal stronger bass. The heights I think I have also heard something stronger and clearer.
The nominal impedance is 32 ohm, incidentally the same size. Both can therefore also on MP3 players loud sound enough.
Other:
The cable has shrunk at 420 K of 1.5 m to 1 m. This is ideal for MP3 players, as you have to store any unnecessary cables. However, the 1,5m long cable would be cheaper for the PC operating.
The folding system has also changed slightly. The earcups are now side by side folded.
When K 412 they were placed yet another. Thus, the K 420 is indeed flat, but requires a little more space.
The practical carrying case is both.
Conclusion:
Both models are ideal for the MP3 player mode, for the price is hard to find something better.
The K 420 justifies its opposite the K 412 slightly increased costs by a slightly better processing and significantly improves comfort.
The purchase aurally not worthwhile for owners of K 412, however.
Overall, I would highly recommend both headphones, the K 412 is but unfortunately hardly available.
Finally, I wish a lot of fun while listening to your favorite music with the AKG's.
