I’ve had time to listen some more and am pleased to be able to say I was wrong. In my first post I mentioned I changed the tips to Comply’s as none of the Sennheiser items fitted my ears, normally this isn’t detrimental to sound quality, in fact it’s the reverse making most IEMs more natural sounding, but in this case it didn’t help as they dulled the highs making the IE 8 sound fIat and boring.
Changing to the Sennheiser large foam tips the sound became brighter and therefore more balanced, and similarly with the twin flange mushroom tips. In the case of the former if I move my head even slightly the seal breaks, and in the case of the latter it takes a while to adjust them to seal properly so neither are perfect for me but this is obviously a very personal thing and the wide range of supplied tips will probably allow 99% of users to find one that suits them.
By comparison with each of the other IEMs I own there are minuses to be found, treble extension is less than the ER4-P and the Triple Fi, nor do they sound as fast and agile, bass is possibly less tuneful than the Triple Fi, and perhaps less deep than the UM2s, but switching back and forth between them hides the strength of the IE 8; whatever you listen to, rock, jazz, reggae, classical, they sound at least very good and you can listen without feeling you’re missing out, which is something I can’t quite say of any of the others. When I stopped switching from one to another and settled down to listen to some music after an hour or so I was thinking, I really enjoyed that album, I wasn't thinking about any aspect of the sound - frequency response, dynamics, soundstage etc. so they do enable one to become lost in the music, and for me that’s what it’s about.
However I did realise that what I was listening to was much more like my headphones than any of my IEMs, and comparing them with my Koss PortaPros and Sennheiser PX 100s proved this. This left me with a couple of dilemmas, as I say, I think they are very good IEMs but some people will compare them to much cheaper portable headphones and decide they aren’t worth the extra money, in the UK the IE8s are more than £200, and the PX 100s are about £25, so it is a lot more for the improvement in sound quality, the isolation, and form factor.
The other dilemma is that as the IE8s provide sound isolation a fairer comparison would be with closed back phones (I don’t own any) and because they have dynamic drivers an alternative comparison would be with other high end IEMs using dynamics (I don’t own any, and there aren’t that many available either). So I think this means that I am not the best person to review these further, and will be very interested in the comments of others.
To summarise, for me the standout features of the IE 8 are the overall naturalness of the sound, the quality of vocals (I have yet to hear an IEM that can get the emotion in a singer’s voice across as well as these do), and the width of the soundstage (they sound more like headphones and with certain recordings the sound seems as if it is actually outside of your head; very rare for an IEM). If I have one remaining criticism, the treble could do with a little more extension, although this does mean that I can happily listen to some brighter recordings which I can’t on my others IEMs.
To answer a couple of questions; the bass control works very well, but as the base is already very full at the lowest setting probably only a few people would use it. Existing owners of the UM2s may feel they haven’t got a sufficient increase in sound quality to justify the cost, and some may prefer the sound of the UM2s anyway.