the headphone work perfectly the first time I use they . put they back on the cradle to charge . the next time I go to use they , all I get be hissssss . call sennheiser . the problem be everything under the sun ... but the headphone : I do not have the volume turn up loud enough , I apparently be incompetent to scan through the dial from one end to the other , I do not have they plug in correctly , blah blah b ! b ! blah ! be tell to return the product ; would be 2 to 3 week turnaround for either repair or replace . I ship they to Sennheiser . no word if they ever receive they . no word if there be a prognosis . no word if there be go to be a fix . no word if and when I might get they back . no word , period ! Communication suck ! I email they , get a generic reply state that it would be 4 week turnaround . if you be think you be get these at a good price , tack on a extra $ 9.35 cost to ship they back to Sennheiser .