The delay attribute (the delay time) of a delay~ object can be specified with tempo-relative timing (such as ‘notevalues’) instead of samples. This example shows a delay time of a dotted eighth note rhythmic value, at whatever the current transport tempo is. The transport tempo is 120 bpm by default; a dotted eighth note at that tempo will last 375 ms which, at a sample rate of 44100 samples per second, is 16,537.5 samples.
The delay~ object creates a "ring buffer" into which it constantly records the signal coming in its left inlet. The first typed-in argument specifies the size of the buffer, in samples. The second argument (or a number in the right inlet) specifies how many samples in the past delay~ should look for the signal it will send out its outlet.
The groove~ object plays sound from a buffer~, using two important pieces of information: a rate provided as a MSP signal and a starting point provided as a float or int message. For normal playback, the rate should be a signal with a constant value of 1. (The sig~ object is a good way to get a constant signal value.) A rate of 2 will play at double speed, a rate of 0.5 will play at half speed, and so on. Negative rate values will play backward.
The fact that groove~ can leap to any point in the buffer~ makes it a suitable object for certain kinds of algorithmic fragmented sound playback. In this example it periodically plays a small chunk of sound chosen at random (and with a randomly chosen rate of playback).
The phasor~ object is one of the most valuable MSP signals to use as a control signal. (You wouldn't generally want to listen to it directly as audio because it's an ideal sawtooth wave and has energy at so many harmonics that it can easily create aliasing. If you want a sawtooth wave sound, it's better to use the saw~ object, which limits its harmonics so as not to exceed the Nyquist frequency.) The phasor~ outputs a signal that ramps cyclically from 0 to 1.
If you need a linear signal that repeats at a specific rate, phasor~ can be scaled and offset to provide a repeating line from one signal value to another. In this example, we use phasor~ to directly control both frequency and amplitude of an oscillator.
The real value of phasor~ is that it provides a very accurate way to read through (or mathematically calculate) some nonlinear shape to use as a control signal (or even as an audio signal). Among other things, it might be used to create a "window" shape that can serve as an amplitude envelope for a sound. This patch demonstrates five different ways to create window or waveform shapes with phasor~. We'll discuss them (in good Max fashion) from right to left.
A phasor~ object, like other MSP objects such as cycle~ that use a rate for their timing, can have its repetition rate specified as a transport-related tempo-relative time value (note values, ticks, etc.). So if you want a phasor~ to work at a rate that is related to the transport's tempo, you can type in a tempo-relative time as an argument to specify its period of repetition instead of typing in a frequency.
How do we detect, with sample-accurate precision, the precise moment when phasor~ begins a new cycle from 0 to 1? We need to detect the sample on which it leaps from 1 back to 0. However, because phasor~ is constantly interpolating between 0 and 1, it might not leap down to exactly 0. So we can't just use a ==~ object to see when its value is 0.
Although playback is normally achieved by progressing linearly through a stored sound, other ways of traversing the sound can give interesting results. Moving quickly back and forth in the sound is analogous to the type of "scrubbing" achieved by rocking the reels of a tape recorder back and forth by hand, or by "scratching" an LP back and forth by hand. In this example, we use a cycle~ object to simulate this sort of scrubbing.