My impression of the 1840 is: Bass does not roll off, but is slightly less than the Shure 940. Mids are excellent. Presence isn't as lively as most headphones like the 940 or a Grado or even the Senn 600 series. Highs are excellent. The overall presentation is ultra-smooth and creamy sounding, slightly forward, and basically mids-centric with less emphasis on the ends than most of the competitors.

Edit: Although the headband is a \"double\" with two pieces running in parallel across the top of the head, those pieces are fixed at about an inch apart and don't move.