Tutorials and Topics - Peabody Computer Music

Audio I/O: Audio input and output with MSPMSP interfaces with your computer's audio hardware via the dac~ and adc~ objects andtheir easy-to-use equivalents ezdac~ and ezadc~. If you don't have any special audiohardware and have no need for inter-application audio routing, the default driver on yoursystem will give you stereo full-duplex audio I/O with no special configuration on yourpart.In addition to Core Audio or MME on Windows, there are a number of other ways to getaudio into and out of Max/MSP. Each of these methods involves using what we call adriver, which is actually a special type of Max object. Some of these drivers facilitate theuse of MSP with third- party audio hardware. Also, a non real-time driver allows you touse MSP as a disk-based audio processing and synthesis system, removing the limit ofhow much processing you can do with your CPU in real time.MSP audio driver objects are located in the ad folder located in the /Library/ApplicationSupport/ Cycling '74 folder on Macintosh or in the C:\Program Files\CommonFiles\Cycling '74\ad folder on Windows. These object files must be in this folder called ad(which stands for audio driver), otherwise MSP will be unable to locate them.We will begin with a discussion of audio input/output in MSP in general. Later in thischapter we will discuss aspects of specific audio drivers that are available to you in MSP.First we'll discuss the DSP Status window and how to use it to get information about youraudio hardware and set parameters for how MSP handles audio input and output.The DSP Status WindowAll global audio parameters in MSP are displayed in the DSP Status window. To open theDSP Status window, just double-click on any dac~ or adc~ object in a locked Patcherwindow. Alternately, you can choose DSP Status… from the Options menu.The DSP Status window is arranged as a group of menus and checkboxes that set all ofthe parameters of the audio input and output in MSP. Since all of these options can bechanged from within your patch (see below), the DSP Status window serves as a monitorfor your current audio settings as well.36