Tutorials and Topics - Peabody Computer Music

Audio I/OAudio input andoutput with MSPother tasks without MSP locking them out. The trade-off, however, is that you'll hearclicks in the audio output when the CPU goes over the specified limit. Setting this valueto either ‘0’ or ‘100’ will disable CPU limiting.About Logical Input and Output ChannelsIn MSP 2, you can create a dac~ or adc~ object that uses a channel number between 1 and512. These numbers refer to what we call logical channels and can be dynamicallyreassigned to physical device channels of a particular driver using either the DSP Statuswindow, its I/O Mappings subwindow, or an adstatus object with an input or outputkeyword argument.The adc~ and dac~ objects allow you to specify arguments which define which logicalchannels are mapped to their inlets and outlets, respectively. In the example below,multiple logical channels are in use in a simple patch:In this example, two separate adc~ objects output audio signals from logical channel pairs1/2 and 3/4, respectively. The output of all four channels is sent to gain~ objects whichattenuate the incoming signals and send them to the first four logical output channels, asspecified by the first dac~ object. The input signals are also multiplied (ring modulated)and sent out logical channels 9 and 10. Up to sixteen arguments can be typed into a singleadc~ or dac~ object; if you want to use more than 16 logical channels, you can usemultiple adc~ and dac~ objects. The ezadc~ and ezdac~ objects only access the first twological input and output channels in MSP.The purpose of having both logical channels and physical device channels is to allow youto create patches that use as many channels as you need without regard to the particularhardware configuration you're using. For instance, some audio interfaces use physicaldevice channels 1 and 2 for S/ PDIF input and output. If you don't happen to have aS/PDIF-compatible audio interface, you may wish to use channels 8 and 9 instead. With43