This example shows how you can record incoming data, in this case, changing amplitude values, using the mtr object.
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.
This example demonstrates creating a RAM buffer to hold a 10-second stereo recording, recording live audio into it (with input volume adjustment), and then playing randomly chosen backward clips of that sound, with a trapezoidal window to taper the beginning and ending of each clip to avoid clicks.
Audio delay is achieved by creating a buffer in which the most recent past sound can be stored. Usually this is called a "ring buffer" or "circular buffer", because when the buffer is filled (with, let's say, the past one second of sound), it loops around and begins refilling itself at the beginning, thus overwriting the sound that was stored more than one second ago.
Any given MSP patch cord represents a single channel of audio. If you want to generate or process multiple sounds or channels, you need to treat each sound or channel separately. For example, each sfplay~ object can have multiple loaded sound cues so that it's ready to play any one of several files, but it can only play one sound file at any given instant. And if it's a stereo file you need to treat each channel separately for mixing, processing, etc. This patch demonstrates that.
This patch allows you to try out various filter settings of the biquad~ object, via the filtergraph~ object. For adjusting the parameters you can drag on filtergraph~ with the mouse, or you can send values in its three rightmost inlets for frequency, gain, and Q. The spectroscope~ object tries to draw the spectrum of the signal.
This shows how to record into a sound file, and how to play back the contents of the file. The example also demonstrates how you can use a quick fade-in and fade-out to avoid clicks when doing realtime capture during a performance.