Tutorials and Topics - Peabody Computer Music

Tutorial 16: Sampling—Record and play audio filesPlaying from memory vs. playing from diskYou have already seen how to store sound in memory—in a buffer~—by recording into itdirectly or by reading in a pre-recorded audio file. Once the sound is in memory, it can beaccessed in a variety of ways with cycle~, lookup~, index~, play~, groove~, wave~, etc.The main limitation of buffer~ for storing samples, of course, is the amount of unusedRAM available to the Max application. You can only store as much sound in memory asyou have memory to hold it. For playing and recording very large amounts of audio data,it is more reasonable to use the hard disk for storage. But it takes more time to access thehard disk than to access RAM; therefore, even when playing from the hard disk, MSP stillneeds to create a small buffer to preload some of the sound into memory. That way, MSPcan play the preloaded sound while it is getting more sound from the hard disk, withoutundue delay or discontinuities due to the time needed to access the disk.Record audio files: sfrecord~MSP has objects for recording directly into, and playing directly from, an AIFF file:sfrecord~ and sfplay~. Recording an audio file is particularly easy, you just open a file,begin recording, and stop recording. (You don’t even need to close the file; sfrecord~ takescare of that for you.) In the upper right corner of the Patcher window there is a patch forrecording files.Recording audio into an audio file on disksfrecord~ records to disk whatever signal data it receives in its inlets. The signal data cancome directly from an adc~ or ezadc~ object, or from any other MSP object.• Click on the message box marked “Create an AIFF file”. You will be shown a Save Asdialog box for naming your file. (Make sure you save the file on a volume withsufficient free space.) Navigate to the folder where you want to store the sound, namethe file, and click Save. Turn audio on. Click on the toggle to begin recording; click onit again when you have finished.139