Jonah @ MAKE writes:

The “Visible Sound” project attempts to create a physical version of the sound around it by sewing sound waves in realtime. Although this was just a concept, we like ways of making invisible objects like sound waves into tangible forms.

This concept model looks like a stereo faceplate on a modified sewing machine, but I can’t imagine it would be too difficult to rig up some sound sensing equipment to adjust the width of the zigzag stitch on a sewing machine.