Without proper amplification AKA onboard sound card, they sounded very thin, bass punch is lighter and lack control and also lack of a proper control on the speaker drivers. Basically, the timing, phase and many things sounded wrong and not in tune. (Not slow, just can't get the right timing on starting and ending of a note)

For gaming so far I found no headphone able to satisfy my needs for First Person Shooter. The sound are wayyy too off and fake. However, online games, RPG, RTS still sound fine especially when their BGM kicks in. Sound effect from those source is still fine.

Genre I'm not sure, but I find that the HD668B has the widest genre bandwidth/ very universal sounding which is able to sit next to JH16PRO. Both are my everyday use headphone. A brief sound intro. HD668B has a more foward mids, the soundstage although is available but not wide enough (Many headphone in this range fail in soundstage), I find it to be the most ideal frequency response where the amount of high, mids and bass is very balanced and at the right amount. The sound is more clinical/ studio like and very revealing of your sound system. The only complain is that I wish it has slightly more lower bass so it can vibrate more and not just giving you midbass punch.

HD681 (RED) has a more laid back sound in the mids, able to reach lower bass notes (Some people think the amount of bass on this is higher but to me I think it has the same midbass punch just only it has the ablity to hit the lower notes so it gives an impression of better bass) It is more warmer than HD668B but is not as revealing as HD668B. This headphone emphasis on treble and bass with more laid back mids and also more comfortable to wear. Besides those differences both the HD668B and HD681 are interchangeable and you won't notice it at all when you switch them unless you AB both of it at the same time. The only thing that is noticeable of HD668B is the requirement for a better amplification.

So it all boils down to whether if you want to get an amplifier or not in the future. The HD668B can scale up so well that it can benefit from a high end amp while HD681 does not have that ability to scale up to high end amp though still will improve from an amplification. If you do choose to get an amp for HD668B look for amp that can supply more current than voltage because they are current sensitive and not voltage. In other words, look for amplifier with higher Mw/ Miliwatt ratings instead of how much voltage they can suppy.

So far the only place I know that can try some of the superlux is in Intrasco in pasar road or you can give Trio a pm and see if he has any of his own unit for you to test. All his headphone are ship directly so only ask for his one, don't ask for demo unit.