Have you ever seen those multi-windowed videos of people singing or playing and accompanying themselves?  Ever wanted to play a duet with yourself or a full arrangement, but have no to few friends?  Thanks to advances in modern technology, apps on your smartphone can let you do just that.

For example, an iPhone app called Acapella, let's you record multiple parts separately and then allows you to combine them into one video together.  The app also allows one to record a part, send it to a friend, and combine the separately recorded parts together from a distance.

This is how the process works:

1. Practice the music

2. Practice the other music part too!

3. Record the first part with a click track

4. Record the second part

5. Review the individual parts to check for mistakes

6. Render the video together

7. SUCCESS!!!

 The mandolin is a stringed instrument that was invented in Italy. It is used in lots of different styles of music from all around the world. It is tuned just like a violin, but each string is doubled so it has eight strings instead of four.