[moocow111]

It has now been a year since I've owned my M50s, and I think I really need to upgrade now. I loved the bass on my M50's, so keep in mind that I'm looking for a lot of bass. I'm not sure whether or not to upgrade my headphone amplifier, unless I need to. My budget is around $600-700.

 

 

[moocow111]

Bump.
 
I've been reading good reviews about the Shure 750DJs and the Shure SRH840. How do those perform in comparison to my M50s?

 

[DeatHaze]

If you're into bass the Ultrasone Pro 900 have supposedly some of the best hard-hitting bass around. The price ranges from $320-$500 so with your price tag you could probably grab a nice amp to juice up the low-end even more!

 

[Yoga Flame]

Have a look at Smeggy's Thunderpants. They are known for tremendous bass, as well as the clarity that comes with being orthodynamic headphones. I've seen used ones go for around $400-$500. You'll need a good amp for them, and some recommendations are in the thread. Have not tried them myself.
 
Sennheiser HD650 is another contender. In my experience it is a clear upgrade to the M50. Bass is slightly less in quantity than my M50s, but it is much clearer. And it's certainly still bassier than most of the other high end headphones. The HD650 has less treble than the M50. Some don't care for that aspect of the sound signature, and call it "veiled". I think it's fine to my ears and leads to a less fatiguing listening experience. Needs a good amp to sound its best.