What does "unplug" mean?

I appreciate to your explanation.

And you're welcome.

Right. Don't have to be plugged in to have music.

Un-plug singing?

Is that the phrase they used? It's 'singing because you like to, not because of any "payment you'll get" or "cause that needs support".'

Perhaps it means the most simple instruments?

No, youless, acoustic is much more sophisticated than that. Take a simple example; the guitar. There are 2 basic types. All have strings and frets, but whereas an electric guitar plugs in and produces sound electronically, an acoustic guitar has a hole beneath the strings and doesn't plug in, in fact it doesn't have a cable, it produces sound by vibrating strings, amplified by the hole - acoustically. Most 'pop' bands play electric guitars - they're loud, most folk groups use acoustic guitars - a quieter, gentler way of providing musical accompaniment.

Yes. There is a different type of mood when a song is played on acoustic instruments.

Then perhaps you can hear to the singing clearly.

So it will be a challenge to the singer.

It is a very clear explanation and easy for me to understand.

This is a good answer,I think that without all the electronic devices is impossible.