Hi All, 

I recently bought the WH-1000MX2 noise cancelling headphones.  I noticed when I first turn the headphone on, and start listening to music, anywhere from 1 min to 4 mins, I hear a bell sounding noise. I think it must be a notification but when I look at my phone, there are no messages or notifications at all.  The bell sounding noise only happens once and then I don't hear it at all.  If I turn it off, and turn it back on, again, I heard the bell sounding noise once again, after couple of mins, and then all good.  Anyone knows what this sound is?