Sennheiser IE 8 In-Ear Headphones

Pleasing headphone to own, lots of character and ability. I really liked the fun sound of this headphone and that's been enough to talk down about 'cold' and 'analytical' headphones since then. 
Sounded a little out of my phone. Drove them with Ibasso D10 and they sounded nice, was quite a large rig to carry and I never forgave them for that. 

DOI: I don't get to listen to new gear a lot so I may not be any use at answering questions about comparisons to anything other than my own stuff (which may or may not be considered esoteric). I was (and am) a full-size hi-fi person so my tastes in this will clearly colour what I look for in head-fi. I tend to value realism of tone for well-recorded voices and instruments but for orchestral works and pop/dance music, I prefer a neutral-warm musicality and dynamics.
 
 
Initial set-up:
Box:
Carry case is lovely but clunky and useless for in-out day-to-day carry. Cable is nice, a useful length and non-microphonic unless you're really scraping it. The clip helps.
 
Eartips:
Best in box for my smallish ear canals were the medium single-flanges - absolute best were cut-down Comply foams, which are crazy expensive in the UK and being cut-up, only last a few days of hard wear before the seal goes. Ended up getting Proguard silicone tips which I use to this day (which reduces total comfort and congests the sound but was a reasonable trade-off for durability). I wore them over-ears with the cable guides as I run around a lot.
 
Source/Amp:
iPhone 4 w/ ALAC then added a BSG cmoy tin-amp with LM4562 (gain 6) and a Tangent-design Pimeta v2 built by myself as a high-end build with BB OPA827 x 3 (627s were waaaaaay too pricey). Lately, I've been using an iPhone 5S with the Onkyo player app and an iBasso DX80 with Lurker's firmware (ALAC and Hi-Res FLAC)
 
A Few Thoughts on the Sound:
Initially, crazy bass which sounded bloated and horrible. After running in on the cmoy for a few tens of hours, it started to clear so I persevered and the muddiness disappeared. I've always kept the IE8s at the lowest bass setting and worked on optimising the seal. There's a lot of bass and can be a bit 'splashy' and it doesn't extend all the way down but the quality even with the well-documented mid-bass hump is a lot of fun with e.g. The Prodigy and Nine-Inch Nails and doesn't obscure the rest too much. Highs are slightly rolled-off but this helps those, like myself, who are very sensitive to sibilance or 'hot' recordings. Detail is good but micro-detail and subtle changes in e.g. the background dirge of Nightwish's Taikatalvi certainly needs a better player than a phone - the upper-range smoothness and the high sensitivity/low impedance probably don't help. Overall, the IE8 is smooth: it forgives low-quality rips, voices (esp. female ones) are clear and with the right recording have a flutey quality that sounds lovely though isn't necessarily the most realistic e.g. an opera recording like Kleiber's 1977 La Traviata. That being said, I played Sandi Thom's 'I Wish I Was a Punk Rocker' for the first time through the cmoy w/ LM4562 and the voice in my right ear was so 'real' I jumped sideways on a busy street...
 
Soundstage is massive, and in a way I particularly like - moreso with the Pimeta and OPA827s: the vocals are in my head but everything else is all around. This can get a bit echo-chamber for some tunes but with particular recordings it gives an 'out-there' effect you can't cheaply achieve even with a full-sized system. Coupled with the Complys, you can forget you are wearing in-ears. I've been known to take my kit onto the street at night when it's quiet and play Florence + The Machine's Cosmic Love far too loudly and dance around grinning whilst it feels like the sound is coming from the sky around me. Seriously. Stop looking at me like that...
 
(The only reason I stopped carrying my Pimeta was the 1-hour battery life - never got the oscillation stable-, the box weighs over a 1Ib and carrying a large metal container covered in switches gets you funny looks on London Underground in this security-conscious day and age.)
 
Overall:
A bargain at the price I paid (~£100) and a very decent upgrade if you like bass. However, perfect fit was an issue for me and it really needs something better than a phone to show off. My favourite to calm a sibilant tune on my rather sizzly but otherwise solid iBasso DX80 (e.g. any of Fun's studio albums - sometimes feels like a very musical white-noise generator). 5 years later and I still go back to them.

Excellent IEM headphones. I usually use my modified HD600's with my hifi system or whilst listening from my mac via my external DAC through my headphone amp, but I recently FLAC'd my entire CD collection (several weeks later) onto an AK Jr, and with the IE8's the sound quality is excellent. (Memories of my first Walkman in 1981 and the impact it made on me as a young boy, the sound was a vast improvement on what I'd heard from any tape player before). The IE8's almost isolate most external noise as it's easy to get a good seal in your ears with the variety of rubber tips that are provided so when the music is playing, all you hear is the music and the reproduction is excellent. From vocals of Andy Bell in 'Am I Right' to Louise Setara in 'Love me Still', to driving rhythms and drums in Lou Gramm's 'Angel With A Dirty Face'. All the varieties of music I've listened to through these IE 8's I've never been disappointed.
Build quality is usual German quality, so nothing to worry about there. They are packaged in a nice sized case that is easy to fit in your pocket, and the cleaning tools and other rubber tips are all stored neatly.
All in all I'd certainly recommend these IEM's, they're not the most affordable if you're on a budget, but if you can save that bit longer, they are most certainly worth it, and I'd be very surprised if you regretted your purchase.