Creepy noises

I love this app to death and I use it all the time when Im studying, but recently Ive been hearing this weird humming noise in the background of the rain option? I mute it but the noise is still there in the background when I turn it on again. Its really quite creepy and Im wondering if theres any way to remix the sound effect so that goes away? Not sure if that made any sense but yeah.

Rachiebelov about Noisli, v1.0.2