It sounds like a Varispeed issue with the Infinity. Here’s some things to try:
- Have you installed the latest firmware version on both the BB and the Infinity? If not, that’s your starting point.
- Disconnect the Infinity from the BB and try playing back the same loop on the Infinity that has speed and pitch problems as when connected to the BB. Does the playback of your loop play to tempo? If the loop stays in tempo and pitch, reconnect the BB and the Infinity. Make sure that the MIDI sync cables are connected properly.
- Here’s a link that might help you with the settings: Getting the BeatBuddy to work with the Infinity looper
Although I experienced the Varispeed effect a long time ago, after I followed the instructions from the link above, my Infinity and BB have played in perfect sync.