Art, I have only heard the K701 for a while on my rig at a meet, but nonetheless I feel you may appreciate the thoughs of a fellow SA5000 apologist.
The K701 has the typical AKG midrange exemplified in the K501, that is very detailed and tuneful, though perhaps slightly over-sweetened compared to a more neutral transducer like the SA5K. The K701 has a bit more bass, and a bit slower bass than the SA5K, though neither to the extent of the HD650. In this regard it is a good middle-ground between the two cans for one who finds the HD650 too dark, but finds the SA5K not bass-heavy enough, and its extra speed unnecessary. The high end is not as prominent as the SA5K, though moreso than the HD650, it's probably pretty close to the DT880 (perhaps slightly softer), with very good extension and detail. The soundstage is the most noticeable difference from the SA5K, it is generally more expansive in each direction, though I found the imaging within the soundstage not quite as holographic as the SA5K.
The K701 represents a good step forward from the K501, which I feel lends itself only to chamber music, string quartets, soft jazz, or other relatively quite music. Based on what I heard, I would still pick the SA5K 100% of the time for rock, metal, electonica, etc; however the more expansive soundstage of the K701 would make me consider it as a change-of-pace for most things classical or symphonic, depending on what kind of sound I wanted. The K701 is certainly no replacement for the K1000, no matter what those crazy Austrians want to claim, as it is nowhere close in terms of imaging, detail, and dynamics.
The K701 has the typical AKG midrange exemplified in the K501, that is very detailed and tuneful, though perhaps slightly over-sweetened compared to a more neutral transducer like the SA5K. The K701 has a bit more bass, and a bit slower bass than the SA5K, though neither to the extent of the HD650. In this regard it is a good middle-ground between the two cans for one who finds the HD650 too dark, but finds the SA5K not bass-heavy enough, and its extra speed unnecessary. The high end is not as prominent as the SA5K, though moreso than the HD650, it's probably pretty close to the DT880 (perhaps slightly softer), with very good extension and detail. The soundstage is the most noticeable difference from the SA5K, it is generally more expansive in each direction, though I found the imaging within the soundstage not quite as holographic as the SA5K.
The K701 represents a good step forward from the K501, which I feel lends itself only to chamber music, string quartets, soft jazz, or other relatively quite music. Based on what I heard, I would still pick the SA5K 100% of the time for rock, metal, electonica, etc; however the more expansive soundstage of the K701 would make me consider it as a change-of-pace for most things classical or symphonic, depending on what kind of sound I wanted. The K701 is certainly no replacement for the K1000, no matter what those crazy Austrians want to claim, as it is nowhere close in terms of imaging, detail, and dynamics.