Well, mostly because of this thread I bought a pair of Proline 2500's hoping they would complement my 650's.
************Updated impressions-see near bottom of this post******************
Interesting phones.
I've got the 200 hours break in so I think my impressions will be valid.
Basically these phones are very, very dependent on recording quality and production values. Maybe even the mood you're in, not to mention the style of music you're listening to.
I've used these with my Mapletree Ear+HD Purist with good results. Also with the headphone output of an old (but recapped) Kenwood 7300 amp (one of the best of the late 70's classic era), again w/good results. With the headphone outs of a Musiland MD10 DAC, results weren't so good (though the headphone outs here are definitely designed for low impedance phones). With the headphone outs of a Behringer SRC2496 (what I would call an upper mid-fi quality headamp) the results were ok.
All were run through the SRC2496 upsampled to 24 bit, 96khz, then through a Musiland MD10 DAC. Also run through DACs of a DEQ2496 and the SRC2496 (both Behringer's FYI) with similar (though perhaps a bit different sounding) results. Perhaps a high end DAC would make a difference, I dunno, I'll leave that judgement to others.
Basically, I've found these phones... different!
And contradictory.
The highs are very resolving (I've been able to make out lyrics never heard before). But that doesn't mean the highs are sweet; yet I wouldn't call them grainy.
The mids are pleasing, yet don't have that shimmery sweetness of the Sennheiser 650's.
Plus on some guitar solos, for example, Eric Johnson doing 'Desert Rose' on the Clapton Crossroads Guitar DVD, which in my mind is one of the finest guitar solos of all time, the 2500's just can't compare to the 650 in sound quality. The 2500's just sound weaker and not as sweetly strong as the 650's do. Yet on the same DVD (highly recommended BTW, EXCELLENT sound quality and production values) Johnny Lang and Robert Cray sound just fine indeed.
On the other hand, on Vladimir Horowitz's 'A Reminiscence' album which is a compilation of some of his best performances, the 2500 blows the 650's away. The 2500's make Horowitz's piano just reverberate, enough so, that that recording brings goosebumps. Hopefully, you have all experienced this and know exactly what I mean. For powerful sounding piano work (even on quiet passages), the 2500's excel; the 650 is simply too polite, IMHO.
Yet on other piano recordings this effect isn't quite there. Go figure.
Lets try a metaphor, the 650's are a Steinway in a heavily draped room, the 2500's a barrelhouse piano with everyone 3 sheets to the wind and singing along. Yet, the piano would still sound perfect if the little Irish tenor sang a sentimental 'Oh, Danny Boy'.
Low's. Not muddy, yet not refined. On the right recording, very powerful and moving, especially at low volumes. The 2500's go very low indeed. On other recordings, simply a little bit wooly, almost like SR60's, but not that bad, of course.
In presentation, cymbals and high hats of the 2500 are upfront yet not obtrusive, and the same with the bass. The 650's are, again IMO, smoother overall and more balanced overall, yet at the expense of being too layed back for my tastes, but, again, not on every recording.
Vocals are good on both. Van Morrison is terrific on the 2500's, not quite as good on the 650's. OTOH, Diana Krall is better on the 650's.
To me the most accurate way to portay the 2500's is that they make most recordings sound like live recordings. The 650's are definitely more studio sounding if that makes sense. Probably because the S-Logic makes the phones more open, yet not quite reverberent, sounding.
BTW the 2500's distort at exceptionally loud levels, the 650's take almost anything without a whimper. But don't let this bother you, it's at ear damaging levels.
If I were to again use a metaphor, I would say the 2500's are like Vince Young, all the tools are there, but with a lack of seasoned judgement and control, yet with good results. The 2500's get it done in a very entertaining way. Yet I can't wait for the next generation in the Ultrasone line, much as I can't wait for the next generation of Sennheiser 650's.
The 650's are Peyton Manning, very knowledgeable, surgical precision, again with excellent results, perhaps a little too cerebral.
Neither have won the super bowl, yet I'd take them both given the opportunity.
BUT, and it's a pretty big but, I'm still looking for Tom Brady.
UPDATE:********Well after 400 hours I've found the highs have smoothed out completely, the bass is extremely tight and extended, voices are very realistic. And most amazing of all, I find myself now reaching for the 2500's 90% of the time. The Senn 650's are still very, very good, but I no longer find them to be "real" sounding. The 2500's, now that I've become more attuned to them, throw a much higher, wider and deeper soundstage. The only other phones I've found close (though I certainly don't claim to have heard them all) are the L3000's which are now nigh impossible to find, or afford for that matter.
I think a lot of my feelings are due to a certain synergy with my equipment (see sig) plus my preference for listening to real, live music, be it at a friends house, club or symphony/opera hall (no stadiums, please!). The 2500's are simply unbeatable when it comes to reproducing ambiance IMO.*****END UPDATE
To sum up, I'd say the 650 and 2500 complement each other. Every time I think wow, this is great, I can sell the 650/2500 (take your pick), I come across a recording that doesn't sound quite right, and the other phone does that recording justice. I've almost begun to mark my cd's 2500 or 650.
I would also say for you sound professionals out there that the 2500's work very well for sound work. And that's a pretty good endorsement, though it has more to do with presentation than refinement. In contrast, I wouldn't use the 650's to do a mix, but that says more about presentation than refinement.
Hope this helps.
