About myself
I'm 38, so my hearing is possibly not the same as in my 20s. I like various music genres, mainly prog rock/metal, blues and some classical music. I'm not into rap/hiphop/EDM so I don't have a strong preference regarding excessive bass quantity.
Some background
I've purchased this item myself, it was used. I have no affiliation with the manufacturer nor was this a sponsored review of part of a loan tour.
Unboxing
Packaging is practical and tidy. No money spent on creating an "unboxing experience".
Comfort and fit
These are really comfortable headphones. The earcups are not very deep, my ears touch the inner surface. However, I don't find this a problem. Clamping force is average or slightly below average.
Sound
Oh, wow. Magnificient tonal balance, a real reference tuning. This word was abused in the recent years, but I think this is really a reference headphone. I don't produce or mix music, nor am I a musician, but I think the Shure SRH840 allows you to get pretty much all the details from your recordings, without emphasizing any frequency range. Very linear.
Bass reaches deep and has plenty of power when needed. Additionally, it is very clean and transparent.
Mids are also great, no complaints here.
Treble is extended, detailed and airy. Being a closed back headphone, soundstage is not the best, but still very good.
Overall, I'm loving these headphones. It has very low distortion and really reveals a lot from the music.
Comparisons
I have no direct comparison, as the only other closed back studio headphone that I've listened to is the Beyerdynamic DT770 Pro (250 and 32 Ohm versions). Those sounded somehow unnatural to me, especially in the higher frequencies. Those also sounded very closed compared to the Shure SRH840.
Sources
Easy to drive, but make sure to use a source with low THD+N, as the headphones are very revealing.
Conclusion
I can only say good things about the Shure SRH840. Excellent reference sound, at a very low price.
I think if Shure made it ten times more expensive, it would be even more popular...