I compared the K812 to the PS1000 directly a couple of times. Once these were similar headphones with different imaging and slightly different tonal balance - the K812 were more even. Another time the PS1000 seemed to sound drier so I decided to mod them. This made them sound closer to the Sony R10 - more nuances on the midrange and softer treble. Overall, I prefer the PS1000 to the K812. This is actually intresting but I realised that the K812 have lowered tonality in the mid-section. When I put the HD800 and the T1 on my head, I heard the same midrange timbre and "height" compared to the PS1000. So, the K812 are a bit different which I don't mind actually.
Regarding comparison to the T1, these with a high serial number are far from the K812 sound. They have darker nature (not tonality, if you know what I mean), the highs have different hue, kind of gold against silver (neutral) in the AKG. Then comes the bass which plays a background role in the Beyers while being one of the strengths of the AKG. I have used an amp with very low output impdance, below 0.1 ohm which on the other hand is able to make the T1 clip on bass when adjusted very loud, so power and drive is enough. This is not an amp related issue as other powerful headphones sound clean at the same volume level,. i.e. HE-6. So, back to the topic, I assume both the K812 and the T1 were well amped and showed quite different natures. Actually, I found the K812 to be a mix of the T1 and the HD800 at the first contact but looking for a one and only similarity, the Grado PS1000 comes to mind and the differences are as follows:
- Grado have more weighty treble which doesn't mean louder.
- AKG have darker midrange but I partly blame their cable for this. I heard an alternative cable too short to confirm for sure.
- The AKG's bass is better balanced
- The Grado have better imaging of furthest soundstage layers while the AKG have better presence of the sounds and voices located in the front of the scene
- There is no smooth "halo" surrounding sound pictures on the PS1000 and no issues with tenor and mezzo-soprano voices (yet famous tizziness
- The AKG are susceptible to the source that you use with your amp which is strongly related to holography. Once you can hear them sound centric, another time most sounds locate outside your head and all of these using the same headphones (K812 of course), amp and IC's.
Finally, I find the K812 more tweaked and flavored than the T1 for instance. The latter sound more honest to me despite probably lesser technical abilities. The same applies to the HD800. I believe that the K812 become an outstanding headphone after some months or years, when the lessons learned from initial production get introduced. This actually happened to the T1 and the HD800 which is not only heard but measurable and visible in the construction. I prefer the new sound of the HD800 and T1 to the point that there was a time I thought the T90 were better than the T1, prior to hearing the new version of the T1.Edited by majkel - 3/16/14 at 1:38am