This near-real-time audio stream originates from a microbarograph at Cambridge, MA, USA (Raspberry Shake station R199D). The low-frequency sounds of the atmosphere have been sped up by a factor of 100× to make them audible. As a result, frequencies have been transposed upward about 7 octaves. Each successive audio program (separated by a brief pause) compresses the last 12 hours into about 7 minutes (exactly 07:12) of listening time.

This sensor responds to much higher frequencies than many of the others featured in the Earthsound Project, although most of its signals are still too low in pitch for human ears. Most are of human origin: commuter trains (the swoosh that occurs twice per hour during the day), vehicle traffic on a nearby street, chirps and whines from air conditioners and heat pumps in the neighborhood, and the snap as the main exterior entry door to the building opens and closes. Some of the sounds are of mysterious orgin. The city is a noisy place.