Convolution is one of my favorite sound design techniques. Most people who have heard of convolution have only ever known it as a footnote in a differential equations or probability course, an inscrutable trick for calculating sum distributions or simplifying inverse Laplace transforms. But convolution can also be used to make a recording sound as though it was made somewhere else or to generate new sounds with complex, unexpected timbres. I wrote the Convolooper as a tool for my own music production: I often use convolved sounds in my music and have long wished that I could interact more directly with the source material. It takes two audio files as input and allows you to select regions from each file to convolve with one another. Right now its main purpose is sound design (and just to play with and listen to), but with some improvements it could also be a live performance tool.