LiveLooper is simple double mono looper with reverb and record options, made for improvising with acoustic instruments.
You can set lengths in seconds for both loopers, control feedback (how much sound goes from one loop to another), gain and panorama of sound.
Gigaverb external (by Juhana Sadeharju & Olaf Matthes) lets you control reverb time, as well as damping and bandwidth parameters.
How did this project use Max?
Entirely build in Max/MSP 6.