An odd remote issue ?!

Got a ring doorbell recently with the addition of a wireless (plug to 13amp socket) extension.

The idea being that when anyone comes to the door and the music is on (even loud) I can hear the bell.

My other half has constantly complained that I do not hear it, I have told her it does not ring.

Having tested it we have found that:-

When the music is muted doorbell works fine, when music is on (volume irrelevant) - silence.

Some sort of cutoff for some reason, no idea how to cure the problem !

Any suggestion most welcome (except switch the music off!!!)