I got my hands on an HD-668B today... I still wonder what's up with these AKG clones... Is Superlux paying license fees to AKG so they may use their classic K 240 design for their headphones? One could certainly think so since a reputable dealer such as Thomann in Germany is selling them and they probably don't want to anger the Harman group :-) Let's have a look at the headphone itself... The earcups' construction certainly looks a lot like AKG's K 240 design that has been around for ages. On this one, the outer headband is a little...

Probably my favourite out of the AKGs I have.   The sound is what I would call quite neutral and uncoloured without any excessive bass or treble that may sound impressive at first but can become fatiguing after a while. When it *is* present on the recording though, the K 280 easily reproduces the lowest bass notes down to 20 hz.   With an amp that has some clean power, these phones can deliver insane volume levels without distortion. They're not terribly hard to drive at 75 Ohms and 94 dB/mW, but are probably too much for most portables.  ...