Display Sound waves for Audio recording

How can we display sound waves as displayed in below image..

When user speaks, The yellow bars will animate based on user's volume.

enter image description here

I had gone through apple demo but didn't got anything.

Please guide me.. Is there any reference link available? Is there any sample tutorial available?

How do you display sound waves?

In order to visualise a sound wave, we can use a microphone to transform sound energy into electrical energy. A simple microphone is made up of a very thin membrane with a coil of very fine wire attached. A magnet is positioned so that it is just inside the coil of wire but not touching it.

What device can you use to show a sound wave?

You can see sound waves when a microphone is connected to an oscilloscope. A microphone changes the sound waves into an electrical signal. The oscilloscope then shows what these electrical waves look like.

Check this sample project by APPLE. It contains same audio meter as your image.

May be that helps.