Over at the coolarduino site they have been experimenting with sound localisation - which is the process of determining the location of noise and doing something with the information. In this case the hardware has been mounted on a pan/tilt device so it can "follow" the source of the noise. It is based around four electret microphones mounted on some protoboard with some basic circuitry. The complexity is in the software, however a full description and tutorial is offered which explains the theory. And by sampling at different frequency rates, the device could even detect a certain type of noise, and track that. Very interesting, for example:
To test audio sampling yourself you can make an easy start with a simple electret microphone board, and our Freetronics MIC: microphone and sound module is perfect.
The MIC: contains an integrated dual signal amplifier converts the sound to separate channels for pulse / frequency measurement, and sound volume (pressure) level. Designed to connect straight to an Arduino compatible microcontroller, Analog to Digital converter, or many other circuits. For more information and to order click here.