Bought this PSB M4U2 for a few days now,, super happy and excited - bought it from a headphone store.  ( Headphone Bar - w. boardway, Vancouver bc ) I always wanted a noise cancelling headphone with passive mode and uses batteries than stupid rechargeable ones.. and I have been doing my research and listing on headphones for a month before purchase and now my wish has come true  + this headset has a amplifier mode ,, which makes the music sound lively and hearing the vocals are super clear and clean sounding. I feel that the amp mode is the best...