I have had these Denon NC-600's for a few weeks now. My main attraction to them was the sound quality, and the fact they can be used perfectly well without the noise cancellation function engaged.
However.... I have uncovered a strange pheonomen with them: When used with my iPhone when the NC function is switched on the sound drops by a tiny, almost un-noticable amount, the qulaity stays constant. But when plugged in to the laptop the NC function inceases the volume by a marked amount, plus the sound become brighter with more treble and nicer vocals.
(Note - I am not using the 'restorer' function at all.)
Why would this be? I actually prefer the brighter sound with NC on via the laptop, as these headphones can be a little bass heavy at times (and are incredibily sensitive).
Has anyone had expereince of these 'phones?