pd22. Bandpass filter in Pure Data

The bp object is a bandpass filter. We will again filter noise. White noise has a uniform frequency distribution. The bandpass filter will pass frequencies in a certain range (the bandwidth).

The bp object needs the central frequency in the bandpass region, as well as Q parameter defining the bandwidth, in a reciprocal relationship.

The savefile subpatch is employed, which was shown in last example.

There is a random object to change frequencies so the signal brightness seems to be changing in time. However it leads to clicks. Later, we will see how to avoid them.

The audio is shown on top and its spectrum is shown below. We note the clicks (denoted by vertical lines, and which are evident at times of 0.3 s and 0.7 s).