The sigmund~ object is not a standard Max object; it’s a “third-party” object for Macintosh by Miller Puckette that you you can download and install on your computer so that it behaves just like any standard MSP object.
Our tympanic membrane (a.k.a. our eardrum) and a microphone are both devices that measure sound intensity. When a sound arrives at our eardrum or at the diaphragm of a microphone, either of which has a certain surface area, the power in that area (i.e. the intensity) is detected. However, the intensity of a sound, as measured by an eardrum or a microphone, will differ depending on the distance from the sound's source, because the sound is being emitted from the source in all directions.
For time-delayed audio, we need to create what's called a "circular buffer" or a "ring buffer", an array of samples to which we record continuously in a loop, and which we can then use always to access the most recently recorded sound from the past.
The trapezoid~ object outputs a trapezoidal shape, rising linearly from 0 to 1 in a certain fraction of its time, then staying at 1, then falling linearly back to 0 in a fraction of its time. Its timing is driven by a control signal at its input, one that goes in a straight line from 0 to 1; so a phasor~ or a line~ is the obvious choice for input to trapezoid~. As the input goes from 0 to 1, the output draws the designated trapezoidal shape.
This patch requires the abstraction for hexagonal radial panning to be saved in the Max file search path with the name "hexagonalradialpanner~". It demonstrates the 6-channel panner, and shows how the sound can be moved around the space in a repeating circle by using a phasor~ to supply the panning angle.
This patch shows an appropriate interface for a flanger, including dials to control delay time, flanging rate, flanging depth, and control over the mix between the dry (unaltered) and wet (altered) signal. Control over the dry/wet mix is a good thing to include in most audio effects.
The technique of flanging in computer music refers to a changing delay time applied to a sound, usually by modulating the delay time with a low-frequency oscillator (LFO). The continuously changing delay time causes a subtle—or not-so-subtle—change in the pitch of the sound. When the flanged sound is mixed with the original sound, the two sounds interfere in continuously changing ways, creating a charactistic modulated filtering effect.
A good way to mix two sounds is to give one sound a gain between 0 and 1 and give the other sound a gain that's equal to 1 minus that amount. Thus, the sum of the two gain factors will always be 1, so the sum of the sounds will not clip. When sound A has a gain of 1, sound B will have a gain of 0, and vice versa. As one gain goes from 0 to 1, the gain of the other sound will go from 1 to 0, so you can use this method to create a smooth crossfade between two sounds.