Was looking at this thread and I thought that I hadnt used my SRH 940 in a while so I brought them out of its case for a bit of listen time....coming from my Audio Technica M50, the main thing I've always found underwhelming with them was apparent even more to me, which is the lack of bass. I wont call it a flaw, because these are supposed to be "monitor" headphones and maybe Shure created them like that intentionally in order to create a flat sound signature, but on the box of the M50 it claims they are monitor headphones too! It makes me wonder if there is really any such thing as a "flat" sound signature in a headphone or even monitor speaker because you would need another "perfect" source that produced an ideal flat sound which you could use as a reference to compare against, which I dont think could exist because everybody's hearing is different anyway. What sounds flat to one person may sound "trebled" to another person.
But anyway, out of the SRH 940, HD 598 and M50, Ive played Someone Like You - Adele several times, and each time I do I can always tell that it sounds the best through the SRH 940. Her voice comes through crystal clear through the SRH 940, while on the HD 598 her voice sounds really good but sounds oh-so-slightly muffled compared to the SRH 940. Maybe its that Sennheiser "veil" they always talk about.
Another song that sounds really good on the SRH 940 is White Nights by Oh Land. Her voice comes in very clear through the SRH 940 compared to the other headphones, but again the lack of bass of these cans is apparent in the drum and bass lines of the song. Probably unsurprisingly, this is where the M50 really shines over the other cans; with the right source and EQ, I can feel the "thump-thump" of the drums and bass in this song which makes it come alive in a way that the SRH 940 cant.
I usually use my iPhone to listen to music nowadays, and make use of an SRS iWow adapter through the line out. This is probably the single most effective piece of audio equipment I have bought in the quest to make my music sound better. I hardly even use my E7/E9 with the computer anymore ever since getting the iWow. The adapter dramatically improves the sound quality of the music, in all aspects but especially in terms of bass quality and quantity, which helps the SRH 940 a bit since it is such a bass-light headphone, but when I use the adapter with the M50 the difference is night and day. The M50 actually vibrates on my head if I pair them with the adapter and listen to a bassy track.
I also use the Equ app on the iPhone to further increase the sound quality of the music, since the default iPhone equalizer can be insufficient at times.
Dont know if this is an ideal EQ curve, but as you can see its a slightly u-shaped EQ curve boosted across the whole frequency spectrum, which I use for all the headphones and earbuds I listen to with my iPhone. The boosted lower end frequencies again help improve the bass response and impact in the SRH 940 a bit more, but not by much, which may be the way its supposed to be.
This is not to say that the SRH 940 doesnt handle bass well, I can hear that it does have really good bass extension which people have said, but its impact that we are talking about here. Impact. If only the SRH 940 had more bass impact....
I've not heard the SRH 840 before but going by what others have said, it seems to have the bass response and impact that the SRH 940 lacks, even if its in the form of an undesirable "mid-bass hump". The SRH 940 is such a detailed headphone with what I would describe as a treble-leaning sound signature, which I like, but if there was a way Shure could create a headphone with the treble and detail of the SRH 940 and with the bass impact of a headphone like the M50 or the SRH 840 as some have said, and perhaps the comfort of the HD 598, that would be the ultimate headphone.