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Tempo-relative timing for MSP LFO control

The MSP phasor~ object is frequently used as a low-frequency control signal for audio. Because it is often used to control other signals over a specific period of time, phasor~ can use tempo-relative timing, too. The frequency (rate) of a phasor~ is normally specified in Hertz, but you can alternatively give phasor~ a time interval, using tempo-relative time units, and it will use the inverse of that to determine its frequency.

Phase distortion synthesis in a poly~ subpatch

This shows an implementation of phase distortion synthesis in MSP—using the phasor~, kink~, and cycle~ objects—in a patch that is designed to be used inside the poly~ object. For an explanation of this sort of phase distortion synthesis, see “A demonstration of phase distortion synthesis.” The main point of this example, though, is to show how a synthesis patch can be designed to respond directly to MIDI input.

Constant power panning using table lookup

In "Constant power panning using square root of intensity" we used the square root of the desired intensity for each speaker to calculate the amplitude of each speaker. However, square root calculations are somewhat computationally intensive, and it would be nice if we could somehow avoid having to perform two such calculations for every single audio sample. As it happens, the sum of the squares of sine and cosine functions also equals 1.

Constant power panning using square root of intensity

The intensity of sound is proportional to the square of its amplitude. So if we want to have a linear change in intensity as we go from 0 to 1 or 1 to 0, we need to use the square root of that linear change to calculate the amplitude. This example patch is exactly like "Linear amplitude panning", except that we consider the linearly changing signal from line~ to be the intensity rather than the amplitude, and we take the square root of that value to obtain the actual amplitude for each speaker.

Linear amplitude panning

The simplest and most common way to localize a sound in a stereo field is to vary the relative intensity between the two speakers. To make a sound seem to move from one side to the other, for example, you can start with the level of one speaker set to 1 and the other speaker set to 0, then gradually turn one down to 0 as you bring the other up to 1. This patch demonstrates a direct linear pan from one speaker to the other.