Making Sound Machines Multiplikand - Review and DIY tutorial
Multiplikand is an active mix/mult for audio and CV, with optional DC filtering. A switch allows you to sum top and bottom channels (e.g., for a stereo send/return), or all four channels together (e.g., for a drum kit). Pin headers in the back allow you to connect to an Arduino or similar, making the Multiplikand very suitable for installation art.