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The Sound of the MBTA

This is a sonification of Boston subway card swipe data, as found here.

Each beep represents 300 card swipes at an underground T stop in Boston. The pitch and position in the stereo spectrum varies depending on the line (Orange, Green, Red, and Blue).

In the background, you'll hear a 4-note chord. Each pitch represents one of the four subway lines. The volume of each tone is determined by the current throughput on that line, as determined by a moving average. The pitch of the chord rises and falls with the overall throughput.

Our auditory sense has some interesting properties. Unlike our visual sense, we have the ability to easily discern both large and small differences in pitch. (When rush hour starts to calm down around 8:40am, you can immediately hear the slight dip in frequency.) At the same time, the pitch arc of the entire day is clearly apparent.

Built with Processing