linear interpolation

This patch demonstrates the sound of linear and exponential changes in pitch and amplitude.

This demonstrates a linear interpolation formula for achieving a weighted balance of two signals.

As explained in MSP Tutorial 2, in order to avoid creating clicks in audio when you change the amplitude, you need to interpolate smoothly from one gain value to another. Example A in this patch shows how to use the line~ object to do that. The gain value from the number box is combined with a transition time in the pack object (10 ms in this case) and the two numbers are sent as a list to line~.

For linear interpolation of a MSP signal, the line~ object sends out a signal that progress to some new value over a certain amount of time interpolating sample-by-sample along the way. The input to line~ is a pair of numbers representing a destination value (where it should eventually arrive) and a transition time (how long it should take to get there). It can receive multiple pairs of numbers in a single message, and it will use the pairs in order, starting each new pair when the previous transition has finished.

The line object sends out a periodic series of numbers that progress to some new value over a certain amount of time. The input to line is a destination value (where it should eventually arrive), a transition time (how long it should take to get there), and a time interval between outputs (how often it should send out intermediate values along the way). The left part of this patch shows the use of line to generate integers that are used as pitches.