Been listening these few hours. Came used from German amazon. Well... of the box and with Galaxy S2 plus sounded very mediocre. Attached to computer and Fiio E6 middle of them. Windows bass boost +21db. Much better now. Also did McGyver foam stuffing to raise pads. Helped little, but thinking order those Brainwavez pads. Seems like every JVC headphone needs modding before being usable. Same was with FX iems.
Listening first some hiphop. Got bored in minutes and changed to what I listen mostly. Metal and rock. I like my metal bassy, pounding me like thousand hammers, oh yes. One song I have been used to separate Headphones from headphones is Insomnium - While we sleep. This melodic death metal song reveals if headphone gets messy with guitars while double bassdrums kicks in. JVC FX iems failed, as did Motorheadphones iems also Sony MDR-ZX600 and V55. Every Sennheiser headphone, Philips Citiscape uptown have been successful and SZ2000 can be added, thank god, to that group. Would been seriously pissed off, because these still cost 220 eur, even used.
But still, this isn't most nauseauting exprience with headphones yet. Motorheadphones Trigger iems with certain EDM songs does that much quicker and brutally. Of course SZ2000 feel more in your body, iems probably messing your balance center in ears more thus causing nausea.
SZ2000 are mostly fun cans, but I miss details compared i.e. to Sennheiser momentum overear. Higher cost even at used does not give good bang for the buck rating to these. Electric guitars sounds little bit hollow. Bass is rich and full, if amplified. If not amplified, sound is really mediocre. Dunno if E6 is capable of revealing SZ2000 full potential, but it is minimum to even get hint of that bass. For me, these sounds actually pretty flat, if bass is not raised by eq. Wish JVC would do version without needing to amp, clearer electric guitars and better pads. Would be a winner for me.