SInce I've bought them, I let them burn-in 24/24 for a whole week. Before the IE8's I had the S4 which I found too bassy. The IE8 sound signature is perfect in my view. Not bass heavy at all and a wide soundstage. At first they were maybe a bit sibilant but it's fixed by burn in (more than 150hours). Maybe a bit less laid back would have been better.   I mostly listen to rock (Indie, progressive, classic, ...) and it's great with impactful bass and wide soundstage.   I paid them for 300€(about 400$). A bit expensive when I see people buying...