Distorted sound problem

[Dr Law]

My Galaxy Note 10.1 2014 is a great tablet, use it all the time and never had any problems, but switched it on today, and all the sound coming from it has gone up about an octave! Music, You tube, news reports, everything! People are talking like they are on helium, and it's driving me crazy. I'm on Kit kat, and haven't done any recent software updates or settings changes I'm aware of that could have done this. I'm using my tablet a lot with You tube learning the guitar, so this is a show stopper for me.
Help from anyone much appreciated.

 

[Dr Law]

Update......this sorted itself a day later. No idea what happened!

 

[The_Chief]

Another bizarre case of PFM. Things seem to fix themselves pretty regularly. Thanks for sharing!

 

[Dr Law]

Sorry for the late update, but I figured better late than never, however I'm afraid you've lost me (and even Google) on the meaning of your acronym PFM ?

 

[Kaat72]

Praying for Marshmallow?

 

[Dr Law]

Aaaaaah ..... and probably a DOH! as well.
(Somebody needs to tell Google about this one though).