Speaker + 9-volt + Spring

Here is an experiment, based on the ideas of speaker scratching from the book, "Handmade Electronic Music" - Collins, 2006. I have attached the 9-volt battery to the cone of the speaker; the speaker ground attaches to the negative terminal of the battery, and the speakers positive is attached the spring. When the spring is placed above + touching the positive terminal of the battery, the speaker is activated. Sound is produced. The speaker cone oscillates up and down causing enough vibration to connect + disconnect the circuit at the positive terminal + spring. This combo allows for a simple device that creates its own beat.
Here is a short video clip of the effect: