I think you are getting those crackles from the atoms (number boxes) that are trying to redraw every time they get a new number from the accelerometers. (which is probably pretty often!) That would explain why it only happens you are using the sensors, and why your very sensible solutions didn't work. Just a hunch! I'd try hiding it all in a sub patch, and if that works, you could use something like [speedlim] (from cyclone?) to limit the refresh rate on the atoms.