mc.poly~ Reference

Manage polyphony/DSP for patchers



Use the mc.poly~ to encapsulate a patcher inside an object box, to specify the patcher filename and the number of instances you want to load as arguments to the poly~ object, and to control object processing and routing in the loaded patcher instances.


The mc.poly~ object directs signals and events (messages) received in its inlets to in and in~ objects inside patcher instances, and handles the output of signals or events from instances of the poly~ object using the out and out~ objects. Unlike mc.poly~, the audio inputs to patchers can be instance-specific using multi-channel inputs, and the audio outputs from patchers are not mixed to a single channel but appear as a multi-channel output.


patcher-name [symbol]

The first argument must specify the name of a patcher to be loaded which already exists and is in the Max search path. A subpatch window is not automatically opened for editing when a patcher argument is supplied for the mc.poly~ object.

number-of-instances [int]


The number of patcher instances corresponds to the number of available "voices" This number can be any number between 1 and 1023, and may be dynamically changed by using the voices message.

local and flag (0 or 1) [symbol]


With local set to 1, the mc.poly~ object maintains its own scheduler that runs during its audio processing rather than using the global Max scheduler, allowing finer resolution for events generated by multiple patcher instances. The local scheduler is run immediately before processing a vector of audio, as if "Scheduler in Audio Interrupt" were on within the context of the poly~ object. Local scheduling is disabled by default - Scheduler locality is permanent for any patcher which is loaded, and cannot be changed by sending messages to the poly~ object.

'up' and up-sampling-factor [symbol]


Use the up argument followed by a number which is a power of two to upsample local DSP processing on the currently loaded patcher (e.g., up 2 specifies 88200 Hz at a sampling rate of 44100 Hz). Upsampling may be dynamically changed by using the up message.

'down' and down-sampling factor [symbol]


Use the down argument followed by a number which is a power of two to downsample local DSP processing on the currently loaded patcher (e.g., down 2 specifies 22050 Hz at a sampling rate of 44100 Hz). Downsampling may be dynamically changed by using the down message.

'args' and list-of-argument-values [symbol]


Use the argument args followed by an argument value to initialize any pound-sign arguments in the loaded patcher (e.g., args #1). If used, the args argument must be the last argument word used; everything which appears after the word args will be treated as an argument value.


args [20 atoms]

When using messages to specify arguments for a mc.poly~ object's loaded patch, the patch must be reloaded by setting the patchername attribute for new arguments to take effect after initial load.

legacynotemode [int] (default: 0)8.0.0

When set to 1, legacynotemode allows note and midinote messages to use the old (pre Max 8) voice assignment algorithm, which continues to play voice 1. When set to 0, note and midinote messages cycle through the least recently used voice.

midimode [int] (default: 0)7.2.0

When midimode is set to '1', all MIDI messages sent to mc.poly~ will be sent to all voices. Note that this does not apply to mpeevent messages. In order to send all mpeevent messages to all voices, use a '-1' value for the voice argument, eg: 'mpeevent 1 1 2 210 117' (an aftertouch message to all voices).

mpemode [int] (default: 0)7.2.0

When this attribute is set to '1', mc.poly~ will perform direct voice allocation based on the voice argument of an mpeevent message.

parallel [int]

When this attribute is set to enable parallel processing, the mc.poly~ object enables the use of multiple threads to run audio processing for all patcher instances. If disabled mc.poly~ runs all patcher instances in the audio processing thread. The DSP chain must be restarted whenever the parallel attribute is changed. This attribute is disabled it when Max is hosted by the Live application.

Note: At this time, you cannot specify a single subpatcher on a different core. When enabled, this attribute splits up the number of voices between the number of processors available. It is primarily intended for patches that use a significant amount of CPU within multiple voices of the same mc.poly~ object, and the multithreading overhead is primarily useful for larger signal vector sizes (at least 32 or greater). Other situations will not benefit. Using the default threadcount (which is equal to the number of physical cores) is best.

patchername [32 symbols]

The filename(s) of a patcher file or files loaded into the mc.poly~ object. The mc.poly~ object can load different patchers on different voices, specified as arguments to the patchername/patchernames attribute. If there is no voices argument, the total number of patchers specified by the attribute will be the number of voices; if there is a voices argument, then patchers are repeated in a cycle up to the voice number.

replicate [int] (default: 1)8.0.0

Replicate Inputs

resampling [int]

Toggles the use of high-quality resampling filters. These filters are enabled by default.

steal [int]

Voice stealing enable causes the mc.poly~ object sends the data from the note or midinote messages to instances that are still marked "busy"; this can result in clicks depending on how the instances handle the interruption. Voice stealing is disabled by default.

target [int]

The mc.poly~ instance that will receive subsequent messages (other than messages specifically used by the mc.poly~ object itself) arriving at the mc.poly~ object's inlets - for example, The message target 2 routes messages to the second instance. If the target message specifies a value greater than the current number of instances (copies) of the loaded patcher, the message will be sent to the highest numbered instance (e.g., sending the message target 2 to a mc.poly~ object containing only a single instance will send subsequent messages to the first instance). The message target 0 sends input to all instances, and using any negative number value with the target message will disable input to all instances.

voices [int]

Number of Voices

vs [int]

Specifies the signal vector size for the mc.poly~ object's loaded patch. The signal vector size will be set on the next compilation of the DSP chain. The vs message does not force a recompilation of the DSP chain. vs 0 specifies no fixed vector size. The default is the current signal vector size.

zone [int] (default: 0)7.2.0

Use this attribute to set the MPE 'zone' that the mc.poly~ will listen to. The default is '0' (ignore zones).

Common Box Attributes



Sends a bang to the patcher loaded into the poly object. The result of the message is determined by the loaded patcher.



input [int]
Performs functions which are specific to the user-designed mc.poly~ patcher itself.



input [float]
Performs functions which are specific to the user-designed mc.poly~ patcher itself.



message [list]
To send a message to a mc.poly~ instance that starts with one of the words used to control the mc.poly~ object itself, begin the message with the word list. For example, the message list target 2 sent to the left inlet of mc.poly~ will output target 2 out the outlet of all in 1 objects, rather than changing the current target instance to the second patcher.



message [list]
The number of inlets and outlets for mc.poly~ is determined by the patcher that is loaded. The inlets for the patcher loaded by a mc.poly~ object accept both signal and event connections.

The signals are routed inside of the loaded patcher by using the in~ objects for signals or the in object for events. The total number of inlets in a mc.poly~ object is determined by the highest number of an in~ or in object in the loaded patcher (e.g., if there is an in~ with argument 3 and an in with argument 4, the mc.poly~ object will have four inlets. All the inlets accept signal connections even though there may not be an in~ object corresponding to each inlet.

Signal inputs are fed to all instances.


Loads a file when dragging a patch from the Max File Browser to a mc.poly~ object.


Disables all playing notes by sending a message to each instance with a playing note consisting of the MIDI pitch most recently received via the note or midinote message followed by a zero velocity (note off message).



message-outlet-number [int]
Reports the voice busy state for the number specified as the argument out the specified message outlet of the mc.poly~ object.



voice [int]
on/off [int]
Pass through incoming signals. The first argument specifies the voice, and the second argument specifies the state. To bypass all voices, send the message 'bypass 0 1'.


Double-clicking on the mc.poly~ opens a display window where you can view the contents of a loaded patcher.



sampling-factor [int]
Use the down message followed by a number which is a power of two to downsample local DSP processing on the currently loaded patcher (e.g., down 2 specifies 22050 Hz at a sampling rate of 44100 Hz). Downsampling is not dynamic. DSP must be restarted before the change can take effect. Although both up and down are permissible messages to the mc.poly~ object, the down message takes precedence over up.



voice-number [int]
status [int]
Sending the word exclude, followed by a voice number and a one, prevents a mc.poly~ instance from being sent messages via note allocation when the mc.poly~ receives a note or midinote message. By default, all voices are enabled for note allocation. The word exclude, followed by a voice number and a zero re-enables the instance to receive messages when the mc.poly~ receives a note or midinote message.



MIDI-message (2 to 4 numbers) [list]
The word midievent, followed by two to four numbers, sends a MIDI event to mc.poly~. The first three number arguments are the bytes of the MIDI message. The fourth, optional, argument is a detune parameter used for MIDI note messages. midievent messages are intended to be used with the polymidiin object.



voice [int]
note-values [list]
The midinote message is followed by two or more values. While note values are ordinarily two numbers that specify a MIDI note number and a velocity value, any numbers may be used for patches which work differently than the standard MIDI model.

If the second note value is not 0, the mc.poly~ object routes the pitch velocity to the first available instance. If the velocity is 0 (i.e. a MIDI note-off message), the pitch velocity will be sent to the mc.poly~ instance that generated the note. To determine which instance of the loaded patcher the midinote message will be sent to, send a 0 (non-busy) or 1 (busy) message to a thispoly~ object located in the loaded patcher.



message [list]
The MPE event message is a list composed of the symbol mpeevent, followed by 6 integers which specify the Zone First Channel, Zone Index, Voice Number, Channel Number, MIDI Message Number, and Data. This message can be sent to a patch encapsulated in a mc.poly~ object using the polymidiin object.



instance [int]
on/off-flag [int]
Turns off signal processing for the specified instance of of a patcher loaded by the mc.poly~ object and sends a bang message to the thispoly~ object for the specified instance. Sending a 0 as the second argument turns the patcher instance on. The message mute 0 1 mutes all instances, and mute 0 0 turns on signal processing for all instances of the patcher. If all are muted using a mute 0 1 message, individual instances cannot be unmuted until all are unmuted with a mute 0 0 message.



outlet-number [int]
Report voice mutes out of a specified mc.poly~ message outlet



voice-allocated-data [list]
The word note, followed by a message, will send the data to the first in object of the first instance of the patcher that has not marked itself "busy" by sending a 1 to a thispoly~ object inside the patcher instance.



message [list]
The notemessage message is used to send messages to each active voice (i.e. an individual instances of a subpatcher loaded by the mc.poly~ object). The message is sent directly to the mc.poly~ object by means of in objects (When addressing a mc.poly~ object, the first in object in the subpatcher is reserved for midinote messages). Sequentially, notemessage messages follow a note message - the first argument of that message being taken as a pitch for the ID of subsequent notemessage messages. The notemessage messages can be of arbitrary length, and may be unpacked and routed inside the subpatcher. In situations where a note-off message that involves a time duration before its completion (e.g. by the use of an adsr~ object), notemessage messages will be received for processing until the voice is turned off.

Note: The only way to turn a voice off properly when using a notemessage is to use a signal to a thispoly~ object in the subpatcher loaded by the mc.poly~ object (if a signal is not connected to the thispoly~ object , the MIDI note-off message turns off the voice assignment immediately).



instance-index [int]
The word open, followed by a number, opens the specified instance of the patcher. You can view the activity of any instance of the patcher up to the number of voices (set by the voices message or by an argument to the mc.poly~ object). With no arguments, the open message opens the instance that is currently the target (see the target message).



instance-index [int]
message [symbol]
message arguments [list]
The word setvalue, followed by both an instance index (starting at 1) and any message, sends the message to an individual voice of within the MC wrapper. setvalue 0, followed by a message, sends the message to all voices. The setvalue message can be used in any inlet. The instance index specified by setvalue overrides the current value of the target attribute but leaves it unchanged after the message has been sent.



number of threads [int]
The word threadcount, followed by a number, sets the number of threads used to divide mc.poly~ instances' audio processing. The default is the number of processor cores available in your computer. Typically, the number of threads should be set to the number of processor cores in your computer for best performance. This can also be accomplished by sending the message threadcount 0. If a mc.poly~ object has sixteen instances and the threadcount is 4, four of the mc.poly~ instances will process audio in each of four threads.



sampling-factor [int]
Use the up message followed by a number which is a power of two to upsample local DSP processing on the currently loaded patcher (e.g., up 2 specifies 88200 Hz at a sampling rate of 44100 Hz). Upsampling is not dynamic. DSP must be restarted before the change can take effect. Although both up and down are permissible messages to the mc.poly~ object, the down message takes precedence over up.



instance-index [int]
Closes the window for the numbered instance specified by the argument. If no number argument is used, wclose will close the patcher window with the highest numbered index.



The number of outlets of a mc.poly~ object is determined by the sum of the highest argument numbers of the out and out~ objects in the loaded patcher. For instance, if there is an out 3 object and an out~ 2 object, the mc.poly~ object will have six outlets. The signal outputs corresponding to the out~ objects are leftmost in the mc.poly~ object, followed by the event outlets corresponding to the out objects, followed by a voice number outlet.

Signals sent to the inlet of out~ objects in each patcher instance are not mixed, but combined into a multi-channel signal output, one outlet for each out~ index. The number of channels in the multi-channel output corresponds to the number of instances (voices) loaded in the mc.poly~ object.

See Also

Name Description
MSP MIDI Tutorial 3: MIDI Sampler MSP MIDI Tutorial 3: MIDI Sampler
MSP Polyphony Tutorial 1: Using the poly~ Object MSP Polyphony Tutorial 1: Using the poly~ Object