I have em1. they're value for money. You need not use and equalizer to get good sound. It outputs the required amount of treble,mid and bass.
Since i like punchy bass(read: tight bass) i am using ViPER4Android in my lenovo a7000 with Dolby ATMOS off. it is really loud. at loud volumes there is no distortion or reduction in sound when bass note plays. but at such loud volumes there are some frequencies which are not comfortable to ears in the mid range9at very loud volume). ViPER4FX removes that for me in a stage called as "Auditory system Protecton" so no worries at loud volumes.
build quality much better than those cheapo looking skullcandy and sennheiser which are now being faked in ebay and can't distinguish the genuine. so eyes closed I went with cowon em1(yes, i read in TDF about its recommendation)
PS: this is not a bass reflex design. a closed design. the back of the earphone is not a vent but a cosmetic small mesh.
the bass is really really very good without distortion when boosted. I fee like flying in air when listening to this in bus. it will make you dance and sing.
my fried shouted for me from the bus standing nearby in college ground and i was listening to music, could hear him until he came and started to beat the window. nice sound isolation. not complete but you can hear others speaking slightly.
I use these following settings:
ViPER Bass: enabled
Bass mode: natural
bass freq: 50Hz
Bass boost: 17.0dB(max)
Auditory System Protection:
curetech+: enabled <--prevents ear damage by cutting uncomfortable freq(uncomfortable at loud volume, at 70% it is ok to switch it off). and it works.
binaural level: slight
have the red color. stands out from the crowd easily. previously i used Sony Ericsson Bass Reflex speakers that came with w395, w350,k750,k790,Xperia X10. yes, 5 earphones. EM1 is my first IEM.