I'm eventually going to do a shootout between K240 Studio, RP-21, and Q40, since they are all studio headphones that people could use for listening use. I'll include a low-fi rig (computer + mp3, no amp) and a hi-fi rig.
But until then here are some more impressions (these are not from A/B listening tests):
- Q40 sounds like a very accurate/flat headphone. They are almost completely uncolored, and whatever color is there I could not describe in words. The only other headphone I have that comes close to being as accurate would be the DT880 (2003 version). To my ears, the Q40 has more accurate treble, whereas the DT880 has a slightly bright treble. I would say the RP-21 are less accurate than both Q40 and DT880, and primarily suffer from artificial-sounding highs. K240 Studio would be the least accurate, with a very warm sound signature and rolled off treble (the anti-DT880!).
- Q40's physical comfort is about as expected. To me, the vinyl ear cushions and headband are about as comfortable as I would expect from this type of headphone. In comparison, the RP-21's headband is less comfortable because of a lack of padding, but the RP-21 has fairly comfortable earpads as well. Q40 has slightly less clamping force than the RP-21, which to me is a plus. But the Q40 is still less comfortable than the comfort champion in this category, the K240 Studio. If I had to guess, I would say I could listen to the 3 studio monitors for the following lengths of time comfortably:
- RP-21 ............. 2 hours
- Q40 ................ 4 hours
- K240 Studio ..... 6 hours
- Q40 is similar to the RP-21 in how it responds to source and amplification changes. Both sound very good out of low-fi sources, but are good enough to show improvements in source when you go to a hi-fi source. On the other hand, both Q40 and RP-21 do not seem to respond much to amplification, perhaps because they are both very efficient headphones. In contrast, the K240 doesn't sound very good out of low-fi sources, and shows a huge improvement from amplification, probably a sign that it demands more power than the other two.
If you have any specific questions about the Q40 vs. RP-21, please let me know.