I took out one of my earphones and didn't get a pure tone... L & R earphones had the same waving sound even when just listening through one of them... 🙄 When you first played just left ear it was pure... But that's it. Once you played both left and right it didn't matter if I had one earphone or both. How come?
Be sure to DISABLE any filters on your device (surround enhancers, Dolby, Atmos, DTS, bass boost, Beats, echo, reverb, etc.) as they will modify the frequencies and this track will not work as intended. Also, make sure your phone isn't playing in mono mode -- it happens to a lot of people.
Yael Sagi