Have you ever worked with a synthesizer before?
If yes then clearly you have heard about the ADSR envelope control.
This system is used in all types of synthesizers.
I personally haven’t found any synthesizer that did not have these elements, and the reason behind this is that they are very important.
They can be found with different settings, some having their settings in milliseconds, other in percents. For me the percent is a bit abstract and I do not understand how it does work.
Some synthesizers have even a 5th parameter, called Hold, meaning that instead of having an ADSR envelope they have an AHDSR one. Hold is a parameter that keeps the sound at the same volume.