Running music in the background firefox?

I want to listen to music in the background with Firefox during a phone call or conference. I have Windows 10 and have connected my beats to my laptop via Bluetooth. As soon as a call or a sound is played from another app, the music from Firefox stops.

Can anyone help me further?

Load Spotify onto your PC, even with the free version you can skip infinitely.

That's what I wanted to suggest, it's the best choice

I wanted to know how to have music play in the background when another app is playing a sound. So the tones should run parallel

Not correct. You can choose freely and don't have to use shuffle like on mobile, and there are advertisements in between.

Did I say it differently?

They do. In my opinion, Spotify doesn't go out when something else is running.