i am owning a pair of srh440, after 1/2 a year still kicking and going. The bass of this headphone is the "background" style, it does not punch you in ur face but u can feel that it is giving your ear a massage when u listen to bassy songs. Do not be deceive by its's 44 ohm impedence and assume this headphone are good already when connected without an amp. the headphone are a total different animal when u put an amp into the cycle. After amping you can get the rumbling bass going, it does not excel in low bass frequency like 10~40Hz but it hide its downside with punchy and clear beating bass beat in the music while still remaining the clarity to the vocal and highs.
i personally feel that its big bro Srh840 is too bass heavy (with or without an amping), when the bass beat really hard in the music, you will somehow lost you focus on the vocal and listen to the bass beats...i am a vocal lover, this phone allows me to "monitor" the vocal in the music while remain the presentation of highs and lows in an adequate quantity in such way that when i'm bored with vocals and wanna start some head banging, i can focus to the bass easily. the way srh440 sound is very different from Audiophile headphone, i own a FA-003 myself and i can definitely put 003 into my "audiophile headphone" bin while srh440 in my "monitoring" bin. so, what are the difference. comparing to fa003, srh440 will let you hear more of your setup, the benefit of changing the interconnector from copper to Silver plated copper are way more noticeable on srh440 than on fa003 as an example.
yes, Srh440 is not a bass oriented headphone (M50 is !) it will gives you more vocal clarity than bass quantity. it is a good tools for you to really listen to every ounce of detail in your music. It has a small soundstage comparing to fa-003....but don't know why, my urge of upgrading disappeared after buying this headphone. I wish you can listen to the headphone before you buy and experience the shure's signature vocal clarity