Linear fade-in/out of audio
The line~ object is useful for providing a control signal. It interpolates linearly sample-by-sample to a new signal value over a specified period of time, then stays at that new value until it is instructed to change. It expects to receive a transition time in its right inlet (a ramp time), followed by a destination value in its left inlet. Alternatively, you can provide both values as a single two-item list. Its initial default value is 0.