I compared the HiFiMAN HE-500, HE-560, and HE-400i briefly in an audio store last week. Here is what I thought:
- HE-500: Strongest of the three in subbass, just as I was looking for; however, side-by-side with the HE-560, it did not have nearly as large a sound stage, and the treble was less airy
- HE-560: Slightly weaker in the subbass than the HE-500, but overall better listening experience due to better soundstage and somewhat airy-er trebles. Also costs nearly twice as much ($899 vs. $499).
- HE-400i: Shares the larger soundstage and slightly airy-er trebles with the HE-560 over that of the HE-500, but MUCH weaker in the subbass, so much so that it sounded similar to the Grados that I have (known for modest bass but sparkling treble clarity).
The HE-560s were quite similar to my memory of my HD 800s (didn't have them with me in the store, of course!). Both the HE-560s and the HE-400is were more comfortable than the HE-500 (lighter, softer earpads, better headband), and both had "normal" cables, covered with black knit cloth, rather than the twisted pair of silver wires of the HE-500.
A quick listen to my HD 800 as I reread this confirms that its subbass does have some degree of palpable strength, perhaps in line with the HE-560, though not as much as the HE-500. However, it also has the superlative soundstage and upper clarity for which it is known.