The cycle~ object allows you to read from a stored cosine function (use a phase offset of 0.75 to get a sine phase), and does high-quality interpolation to give you excellent resolution even though it only uses a 512-sample table. (See MSP Tutorial chapters 1-3).
But if you want to put a sine wave into a buffer~, here’s a way:
A named record~ object records audio data into the buffer~ object that shares the same name. When the record~ object receives the message 1 (or any nonzero number) it begins recording the audio signal it receives, by placing that data in the associated buffer~, starting at the beginning of the buffer~. When record~ receives a 0 message, it stops recording.
This example is essentially the same as "Basic RAM recording into buffer~", except that it's designed for recording and playing back a stereo signal instead of a single channel of audio. The buffer~ object has an additional argument to specify 2 channels of storage.
To record a sound into RAM, you must first allocate/designate a place in RAM into which to record. The buffer~ object creates a named buffer in memory large enough to store the specified duration of audio data. In this example, the buffer is named "theholdingplace" and holds up to 60,000 milliseconds (one minute) of audio. The incoming audio signal from the adc~ object goes into a record~ object that refers to that memory buffer.
This patch shows several techniques relevant to granular synthesis, playing a stream of short excerpts of recorded sound. (The patch uses one abstraction, called pan~, that's provided in the example titled "Constant-intensity panning subpatch". You'll need to download that abstraction and save it with the name pan~ somewhere in Max's file search path.)
In classic granular synthesis, grains are very short windowed segments of sound, normally from 5 ms to 100 ms in length. A stream of sound grains be spaced at exactly the same time interval as the grain length, or at some greater interval of time. The spacing can even be randomized (some random time interval greater than or equal to the grain length). A single stream of grains is all you can do with a single groove~ object.
Preloading sound into random-access memory (RAM)—as opposed to reading it off of a hard disk—allows you more easily to access any point in the sound file instantaneously, read backwards as well as forwards, access different points in the sound simultaneously, etc.