Last week I came across the Exponential Attack & Decay Envelop (ead~) object in Pd. At first I did not understand how this object worked so I decided to create a simple patch that provides both visual and audio feedback of the signal that it generates. You can download the patch here.
The ead~ object creates an envelope that increases amplitude of a signal logarithmically by a specified attack rate, then brings it back down at a specified decay rate. As you would expect from this description, it requires two input parameters. Both the attack and decay rate are set in milliseconds. This object is often used to create beat like sounds.
The patch is designed to allow you to easily control the attack and delay parameter using two horizontal sliders. The resulting envelope is displayed on the graph underneath. To hear the sound generated by an oscillator coupled with the ead~ envelope turn on the sound at the bottom of the patch. Make sure to switch on the “dsp” as well click on the green toggle button. Lastly, also check that the oscillator frequency is somewhere north of 440.
You can download the patch here.