This quick project records the volume levels of sound, be it music, voices or anything else.
Note: You need to run this in the Flash player and allow it to have access to your microphone for it to work. You can also download it and run it in Scratch.
Adjust the sensitivity and speed sliders to get the pattern to how you want it.
Credit to Lightnin's project 'Hungry Bat 2' upon which this is based: http://scratch.mit.edu/projects/Lightnin/1659457
Lightnin's project uses ideas and code from sierra2600's great Alpha Delta Soundgraph Projects: http://scratch.mit.edu/users/sierra2600