I've tested:
Superlux HD660 39
SHURE SRH 240 49
Audio Technica ATH-T400 49
and of course
Audio Technica ATH-49 M20x
All have in common is the relatively low shielding, which has itself grown not strong against the Superlux 668.
The strongest bass had the Audio Technica ATH-T400, sounded the same but very dull to. He is also the most convenient.
Shure Superlux and have a little less bass, sound for not so dull in the heights. Unfortunately heights were sometimes sharp and annoying.
The Technica M20x is all in the middle. He MMN good bass (lack reference I can not say whether the perhaps too much is in terms of "linearity") and the heights listen to much more pleasant without being dull as the T400.
Overall, the M20x sounds very similar to the 668B.
To fit:
The Superlux 660 has the highest pressure, it follows the M20x, T400 and Shure. The Shure sitting on my head even almost too easy. At faster head movements or look down he slipped. But he is particularly airy during normal wear.
The head padding of the M20x I find very pleasant, the pressure could also be slightly lower. The heat development is ok but rather warm.
Processing I find very good, the cable is properly and there was no need for a exaggerated large jack (the 660 and Shure have the plug after just 5cm flexibly). The material of the ear pads is soft.
Disturbing is only the 3m! long cable. Shortening is not as simple as extend.
I give it 5 stars because I regard him as the best of the tested earphone and the price / performance find it very good.
PS: With terms like "stage", "airiness" "dissolution" I know what to do, but sit up and have fun working in the listener excellent!
