This little amp is a surprise. Alone it is actually not that bad with some HD650's. The sound is typical dark, liquid, and pretty nice to listen to if you're into that sort of tubey coloration.   Later, when you try to put this DAC into a revealing system, perhaps as a source for a revealing amplifier, the surprise is that the uDac 2 is actually quite terrible. And it has nothing to do with anything that has been ranted and raved about, forget the tech specs. The DAC section simply has a flat out horrid frequency response, it's boosting the upper...

These were my first foray into high end, high fidelity sound. They were a true revelation. These headphones were built for my ears, laid back, rich warm mids, deep but controlled bass, the de-facto ultimate headphones of their time.   Treble: Laid back, airy, great sound stage, contrary to popular belief, bigger is not always better with regards to sound staging, some things weren't recorded on a giant sound stage afterall. Liquid cool and never fatiguing, the treble was far from analytical but still revealing of source quality, a transparent...

These headphones are kind of an enigma. They look like cheap crap, feel like cheap crap, and unless you amp them properly, sound like cheap crap too. With a good amp these phones WILL go deep with tight detailed bass. The enigma here is that yes, these CAN sound good, but you will need to spend $$$ on an amp. At that point you have to ask yourself, if you spent money on an amp, should you in turn spend money on headphones? Yeah, you probably should... If you can find a cheap amp that has some real current (it plugs into a wall not a USB port) then...

Sound is only a little better than average at best.   Treble: Analytical sounding and a little bright for my tastes, a little fatiguing, liquid though lacking absolute detail, some air, compressed sound stage.   Mids: On the thin side, but fairly detailed and liquid, lacks defining punch and rich tonality. Voices sound good but lack that palpable richness of say, HD 600's.   Bass: For headphones the size of sliced grapefruits these surprise with their less than ideal bass extension. The bass they do have is decent though, not boomy, well...

Great sound, typical dark Sennheiser tonal balance that I personally like. Sound for the money and construction is 5 stars. From an absolute sound quality falls somewhere short of that, but is quite good for the application/form factor.   Best for rock, beats, vocals, etc, simpler more intimate music types shine. Symphonies are the weak point.   Construction is solid, no worries with these, exercise, put them in the gym bag, glove box, whatever.    Comfort is the one down fall, large ear buds may pain some people over time. They don't...