The tapin~ and tapout~ objects work together to delay sound. The tapin~ creates a place in memory for storing a circular buffer of the most recently received signal. Its argument specifies how many milliseconds of audio it should store. Any connected tapout~ object accesses that memory to get the recent past of an audio signal.
This is a flanger that can easily be used as an abstraction (subpatch) within any audio patch. Simply save this patch in Max's file search path with the file name "flange~.maxpat", and it can then be used as a flange~ object, as shown in the example "Try the flange~ abstraction".
This patch demonstrates a simple implementation of "flanging"—the effect created by making a delayed copy of a sound, with the delay time periodically fluctuating, and then mixing the delayed sound with the original.
For this example to work properly, you will also need to download the additional Max file "mix~.maxpat" from the example "A useful subpatch for mixing and balancing two sounds", which will be used as a mix~ object in this patch.