She in hers. She's watching the telly, I'm amusing myself with whatever I find on the Internet.
I can hear her singing, on her own in the front room, along with a song in an advert.
She may not have the voice of angels, to you perhaps. But she is in tune, and for me the sound is mana to the soul.
The thing is, people hum or sing in those moments when they are alone, relaxed and free. I've been alone and free on the midst of most every set I've ever played. It is, in good part, why I love every gig I play.
If you want to understand, just catch yourself humming a tune.
I love her voice. I know it better than she does.