I would like to start with some background that you don't have to read, although it really helps clarify why I am interested in this comparison. Skip to the last paragraph for the actual question.
Lately, I've become a big fan of Ultimate Ears 600 (renamed Super.fi 5) IEMs which I find to be really great sounding for the price. I bought them based on the measurements at Innerfidelity just out of curiosity and didn't really believe that they would sound great, but, alas, the measurements didn't lie and they do sound truly excellent IMO and have now replaced RE0 as my best price/performance IEM. I now have 2 pairs. lol
I owned the single driver PFEs a while ago - about 2 years ago I believe - and I did not like their sound at all back then. I found them thin sounding, lacking body and decay, even when amped by my reasonably good MiniBox E+ portable amp. I don't know why I thought of them that way considering how popular they were and still are to this day and how many people around here love their sound. Perhaps I needed to spend more time with them to understand their sound signature, or maybe I just wasn't able to achieve a good seal. But I was so disappointed with the sound that I sold them within a couple of days, posted some negative impressions on the forum and never considered purchasing another pair to give them another chance.
About a 2 months ago I stumbled upon Tyll Hertsen's Innerfidelity site and found his Phonak Audeo PFE 121 review. The review was very positive and was backed up by some solid looking measurements which really got me thinking about these IEMs again and wondering why I didn't like them. They seemed to measure better than many other more expensive headphones. Then, some time later I stumbled upon the Ultimate Ears 600 measurements on the same website that looked surprisingly great to me and even better than those of the Phonaks, so I decided that I really needed to give them a try. I did and like I said above, really love the sound. Maybe it's all psychological as I did buy them simply based on the measurements, but I believe they really do sound excellent for my tastes and I enjoy listening to music through them a lot more than with most other headphones I tried.
But anyway, when comparing PFE and UE600 measurements at Innerfidelity, they look quite similar overall and I also read that they both use armature drivers from Sonion, albeit different models. I think UE600 graphs better with superior 30 Hz and 300 Hz square wave response and a quicker impulse response, but the two are otherwise quite similar especially in the distortion graph, where both IEMs show noticeably higher levels of distortion through the midrange vs the lows and highs.
I would really love to hear from those who owned both of these IEMs and compared the two directly. Which one do you like better and why? Thanks in advance for any input. It might save me the trouble of having to save cash to buy another PFE to compare with my UE600 myself, although I may have to do that anyway. lol
Edited by Pianist - 3/20/12 at 6:03pm