For various regions, shopping malls across America (and in other places) are dying. Many have only a few shops left in them. A few, somehow, manage to thrive.

Many Gen-Xers spend their formative years in shopping malls, walking endlessly in circles. The experience of these malls was not only a visual panorama of their shiny flat surfaces, but also very much their acoustics. The indoor stores separated themselves from the indoor mall by using piped in music, which informed shoppers that they were entering a different space. The music used was chosen to signal what demographic the store hoped to attract. Stores for teens played the top 40 that appealed to that age group.

Department stores and the mall itself played more neutral music, trying to signal a more broad appeal. All of this was set in space full of talking, foot traffic, and young people, set against very reflective surfaces. It was not just the music chosen, but the acoustic that differentiated spaces.

Smaller stores had nearby walls, dampened with hanging clothes or other wares, and thus their reflections were different than the more open mall.

As malls disappear, their unique sonic environment disappears also. It’s impossible to recapture what they were like when filled with people, unless you somehow entice people to come in. But the echoes of the sonic space and the dimensions of the architecture can be archived in a form that’s usable for people who would like to experience what being in such a place sounded like.

This usable archive can be made via a short audio file called an Impulse Response. It is a recording of the echoes of the space. Below, you can find instructions on one way to make such a recording.

These recordings should be made, as a form of acoustic ecology and of memory. So the sounds can still be used even as the spaces themselves vanish.

How to take an impulse response with two mobile phones.