Summary: I bought and received them yesterday after reading all the good reviews here and I am in shock to what I actually received. I tried them for 1 day and when I connect Bluetooth with NoiseGuard it makes random scratching and hissing sounds.
Not even as good as same brand/size non-bluetooth headphones
23 June 2013
Summary: Very disappointed with the audio quality, especially for the price. I already have some hd590 and the px200 folding variety, both of which are brilliant, but these just sound like cheap rubbish by comparison, lacking any real bass and having a nasty and uncomfortable midrange.
Everything perfect when batteries are on. Really Bad Service from Sennheiser !!!
VASILEIOS TAGKOPOULOS, Amazon
23 February 2013
Summary: Excellent sound with rich bass, very good battery duration, fast recharge time. All that when batteries are on and NoiseGard on. When you are working them without batteries OR the NoiseGard is off, the sound is REALLY poor!!! ********* Really BAD service from Sennheiser!