I got a pair of SRH840s not too long ago. I got these after reading a bunch of reviews on head-fi and other places that talk about their great sound and they indeed deliver. I pair them with my iBasso D4 Mamba (used as a DAC and amp, with gain on) which I picked up from a fellow Head-Fier not too long ago and they sound amazing.
Here is my 2cents on the 840.
Downsides first:
Physically:
Weight: I find the biggest downside to them is the weight. I got a close friend of mine 440's for christmas and they are definitely lighter. Significantly lighter. Although inertia is still a b*tch for both of them (any quick head movements = fail). They really are large cans.
Clamping Pressure/Headband: Oh, the clamp force on my little head. Maybe my ears stick out and touch the pads that cover the speakers. Or a combination of a lot of clamping pressure and that. I don't have an obscenely small head or anything, to be honest I'm just a normal average sized 19 year old. 5'10. 170lbs. Nothing special. The headband is also large. Even on the smallest size, they tend to slip off if I bend my head down too much. The clamping pressure keeps the cups on my ears to use them as an axis while the headband slips down. On the 440's the issue is not as bad due to the headband being significantly lighter, but even on the 440's the headband is still relatively large and heavy. I read only in one of two of the reviews online about the head size being meant for larger people, but I forwent such comments because of the price (budget, nothing crazy) and the sound (I've also had good experience with the Shure customer service with my SCL2 cables cracking every half year...but that is another story). So this point should be noted to younger Head-Fiers and just those who have smaller heads.
Sound:
Fatiguing: Another downside, at least for me is that I find the music, while it sounds great, not as engaging as I'd like and thus fatiguing. Or maybe its just the clamping on my head.
Leaking: Also, while these cans are closed cans, sound definitely leaks, and if you are close enough, you can hear the music. But this is like within the range of hugging and stuff (as well as dependent on your volume), so its a non issue as most people will not enter your personal space....but you should know it does not block out all sound. So don't listen to things you don't want people to hear you listening to at super loud volumes. (Insert obscene inappropriate jokes here)
Soundstage: I don't know if it is just me, but for some reason I can't get the music to stop playing from behind me. It's like the band is on a stage behind me and I'm standing at the front of the stage with my feet touching the edge and they are playing to my back. Maybe I'm crazy. Maybe I'm just thinking that and then my brain sets up for me to listen to it like that. I really don't know.
Upsides (is that the opposite of downsides?):
Physically:
Pads: The pads on the 840's are indeed loads better than those of the 440. They are soft and comfy. This also factored into why I got the 840s. 440's can be found for ~$80. 840's can be had for ~$150. I figured if I wanted the better pads, I'd prob end up paying $20 for them and $5 for shipping so the additional $70 for the 840s meant ~$25 for better pads and $45 for the better cans. Anyway, just a thought for people with the money who cant decide whether or not they want the 840 or 440.
Sound:
Bass: The bass does not lack. They are no Dr. Dre Beats, but they definitely don't lack. I don't find them to be overpowering at all.
Detail: Instrument separation is amazing. I don't listen to classical, but I can hear all sorts of instruments that I've never noticed and they come out clear. You have to try to listen to the sounds in the background though, its the subtle bass playing in the background and stuff that just become more apparent and clearer. Music is more detailed and just sounds plain nice.
Vocals: Vocals, they sing to me. Oh Cat Power...you beautiful woman you.
Summary:
The cans sound perfectly fine out of my Macbook Pro and my iPod Classic, but do benefit greatly from my dac/amp. My friend's 440 also benefits from the D4, but not as much as the 840. Her 440's aren't completely burned in yet, but from what I heard, I found the detail to be lacking compared to my 840's which have been burned in maybe 50+ hours (probably more...but thats just a ballpark-ish).
I guess what I'm saying is that the headphones sound great, but aren't exactly ones that make you go crazy and want to dance. But it should be noted that they are "Professional Monitoring Headphones" not remotely close to any of those Dr. Dre Beats or whatever that are meant to blast your music and make a rave in your head. They are also meant for people with larger heads. They are heavy. If you can stand the downsides I've found, then get them. They will make you happy. Especially if you have an amp.
Oh, and for the record, I listen to a lot of indie, alternative, rock. I'm also not a music/audiophile expert. I just enjoy my music. I'm only a college student doing computer science, so I tend to sit in front of the computer a lot and listen to music while I work. Take my opinion for what you will. Maybe get the cans and make your own. Cheers.
