It is most impressive when you adjust it to your listening preferences: because the HD660S is designed for a flat frequency response, I turned up the bass on the amp EQ to give the music the fullness and power that I prefer.

The cable is good but not great, comes with 3.5 to 6.35 adapter (for mobile, yes these get powered off my S9 very well), an extra 4.4mm balanced pentaconn cable (first time I saw that) and a 6.35mm cable already in the headphones