Adjust the volume of background music during meditations/self-hypnosis

In Settings I'd really like to be able to set and choose voice and music volume independently on the application.

I find the volume of the voice too loud for the music, and I'd like to be able to lower the volume of the voice and increase the volume of the music during meditation and self-hypnosis sessions. I have to turn the volume down so much so that the voice doesn't startle me while I'm falling asleep that I can't hear the background music of the session, and this is a real negative point on my desire to do the sessions. Although I think they're great.

Kind regards

Audrey