[Burtron5]

I've owned the HE 400S, HE400i, HE500 and HE560.

Some practical thoughts coming through the Mojo Audio DAC and Cavalli Liquid Carbon:

400S comes w/ the velour pads, which gave a slightly loose and less detailed sound sig. I replaced those w/ the Hybrid leather/velour ear pads and immediately the SQ became more detailed, Bass increased (for the better) and I felt they competed and bettered the sound of my HD600's. Later traded for the HE400i's.

400i are a nice step up in quality from the 400S. There is an open airyness to the mids and treble. If you like a detailed sophisticated mid to High-end (read Classical,
acoustic solos,etc) these cans will not disappoint. However, I did not find the lower end to be deep, extended or exciting. Enter the HE500.

500 was a very nice improvement w/ the whole spectrum feeling fuller, richer and detailed. At this point I needed to make it MORE COMFORTABLE for longer listening sessions. I replaced the steel headband with the lighter HE400i headband, and added a lightweight silver cable (which also added air to the sound) and now have a long session headphone that sings! Very happy w/ the weight change and the treble increase w/ the silver chord. On to the more recent HE560.

560 was at first, a revelation in detail and quickness, especially the mids to high-end. I bought classical concertos to specifically listen to these headphones. They are amazingly fast and can reveal a virtuoso solo that will thrill and amaze! There are some incredible artists out there! However, I do tend to like my Rock, Blues and Jazz.
For those genres, I found the 560 too strident, too detailed and simply lacking in the bass, lower mids and overall weight of the playback. Had to let them go...

Upstream devices, different genres, and personal preferences will change your opinion, these were just mine. Enjoy the journey!

 

[eucariote]

Both can be had for the same price? HE-500 and don't look back! I was truly amazed by everything about HE-500, especially the mids. So lush and lovely they were worlds better than the HD600, a known mids champ. I found HE-400 to be way to colored- the big bass and treble sound exciting for the first few hours but gets old fast. For long term listening pleasure and total versatility HE-500 for sure. Sound quality should be your first criterion and since they cost the same, the only criterion.

 

[Music Alchemist]

I was much more impressed by the HE500. Its "baby HE6" nickname is well-deserved! It might be my favorite non-electrostat out of the ones I've owned. (See profile.)

 

[bagwell359]

Life to a zombie thread... Own the 500, 4XX, have owned the 400i and heard the 400S.

Used 500's can be had for $360-440, so call it $400 with probably something like 2 cables and 3 sets of pads included. You can get the various 400* models used for mid-high $100's.

Stock: 500's more and better bass under 70 Hz. 400's mid bass and upper bass bulge to try and hide missing low bass. 400* treble bright but lacking details vs 500. Also 500 has much better sense of placement and overtones. In the mids the 500 crush the 400. Better sound stage, more detail, but also more liquid and suave, Even fans of the 400 tend to cede the mids to the 500.

Mods: 400* does NOT scale very well. Pads and bass damping give the best value (Dynamat helps banish fatuous bass). Amps, cables, not so much. Cannot perform "fuzzor" mod. 500 scales well, amp sensitive, cable, pad, rear screen removal/change, and the Fuzzor mod. Fit with mods and being run by a beefy SS amp, the 500 runs rings around the 400.

All just my opinion of course.