Ah, I see what you're talking about now. There are indeed a handful of classes-- some in d_ctl.c-- (and probably externals, too) which take signal input and ou

Ah, I see what you're talking about now. There are indeed a handful of classes-- some in d_ctl.c-- (and probably externals, too) which take signal input and output some message like "bang" on block boundaries (by using a clock callback). Still, there's no "control rate"-- "threshold~" doesn't output data every block. It outputs data only when the threshold value is exceeded, quantized to block boundaries. At least in my fork (Purr Data), the control outlets are visually distinct from signal outlets. So upon instantiating [threshold~] you can immediately see that it doesn't output signal data.