Hello guys. I want to share my opinion regarding these two units. If you're considering these two, you'll find this thread helpful. I'm a trained musician. I have perfect pitch.
I have both R10 and HM901. I have concluded that HM901 sounds far inferior to R10.
To me, it sounds like HM901's sound is very much reduced in quality and detail compared to R10's.
I have played lots of 24bit / 192 khz classical records, soundtracks, electronic music, etc. R10 sounds at least twice more detailed and refined. HM901 boosts unwanted frequency range such as background noises. Its sound stage isn't bigger than that of R10. It doesn't give you true representation of instrumentation and arrangement of musical pieces. I would say it sounds rather congested and deducted compared to R10.
Also, HM901's UI isn't that superior to R10's. It still has bugs and it's too simple.
I decided to turn back my HM 901. It simply doesn't worth $999. I would keep it if it was $300. For $999, they could have done much better job with current technology. Its price tag is utter nonsense. I work in a music studio and have gathered reference monitors and headphones through many years. From that experience, I can tell you that HM 901 is even bad for reference. It doesn't meet that qualification. You can't really rely on sound of HM 901. This is not how music truly sounds. R10 is closer. R10 can be used for reference.
To my ears, it sounds like people who made HM 901 have never attended classical music concert nor truly enjoy music. They haven't heard how musical instruments truly sound in an ensemble. If they have played music in an ensemble at least once, they can't come up with something like this. Non of music engineers would call this a reference music device. HM901 sounds better than iPod Classic or other cheaper mp3 players, but it's still hard to think of paying $999 for that. R10 is about $650.
Here's my verdict:
Buy R10 if you want true high quality, refined sound and big sound stage. If you're a musician and looking for a reference quality music player, don't buy HM901. It will certainly be a waste of time and money. I will never buy anything from Hifiman again till they make something radically different.
Sound quality wise, R10 is still the best. I haven't heard AK240 yet.
Edited by kawaivpc1 - 7/23/14 at 4:54pm