Originally Posted by olear
How do the HE400 compare with DT880 and HD650?
What are the differences between HE400 and 500?
What kind of amp is recommended?
I've never been a fan of the DT880 though I wanted to like them at the time. The treble is just too sharp for my tastes. HE-400 has some treble spikes, but nothing like that 8.5kHz dagger the DT880 has. DT880 has many fans however. My thinking would be if you wanted a DT880-like ortho, HE-5 maybe a better bet. HE-6 possibly even moreso. HE-400 is far darker even if parts of it are bright than the Beyers.
HD600 and HD650 are two sides of the same coin. HD600 is Senn's flatter more neutral can and HD650 is their slightly technologically superior but basically similar variant that is warmer and with a bigger midbass hump and more rolled off hights. Compared to HD650 HE-400 is very different. It has no overly warmed mids, while HD650 is built from the mids outward. It does share some common treble rolloff, but where the HD650 shows the treble rolloff by design, the HE-400 has carefully placed peaks that feel like full treble without getting fatiguing. HE-400 has the more solid bass depth, and has better instrument separation, while HD650 has a better center image and a more refined or relaxed sound. HE-400 has crazy dynamics when fed by a dynamic amp. HD650 has a narrower dynamics. This can be good or bad either way depending on the recording. Compared to HE-400, HD650 sounds almost bright, despite that it is not. Overall they're two wildly different headphones that compliment each other very well. HD650 and HE-400 are my main two headphones of my collection and compete almost evenly for head-time. HD600 never appealed to me as much as HD650. It's a nice flat headphone that's not as colored to be musical. HE-400 doesn't compete with analytical flatness of HD600 & K702 for example if that's the goal one is shooting for.
wje is the best to answer about the HE-500. From his earlier posts, when amplified well the two are actually very similar. They do have different sound signatures with HE-500 being brighter and warmer, tuned more like HD650. HE-400 would be darker and weightier.
Amp...is all preference. I happen to love both HE-400 and HD650 on my Lyr, and I defintely prefer tube/hybrid sound for them. But I can see how some would like them on a more analytical SS amp as well. They're easy to drive, but the do reward more serious power as well.