mc.svf~ Reference - Max 8 Documentation

Description

The svf~ object is an implementation of a state-variable filter algorithm described in Hal Chamberlin's book, "Musical Applications of Microprocessors." A unique feature of this filter object is that it produces lowpass, highpass, bandpass, and bandreject (notch) output simultaneously - all four are available as outlets.

Arguments

center-frequency [float]

Optional

Unitshz

Sets the initial center frequency for the filter. The default value is 0.

Q [float]

Optional

Sets the initial Q value for the filter. The default value is 0.01.

Hz [symbol]

Optional

Sets the frequency input mode to Hz (the default mode - hence this is the same as providing no mode argument).

linear [symbol]

Optional

Sets the frequency input mode to linear (0 -1).

radians [symbol]

Optional

Sets the frequency input mode to radians (0 -1).

Attributes

Common Box Attributes

annotation [symbol]

Sets the text that will be displayed in the Clue window when the user moves the mouse over the object.

background [int] (default: 0)

Adds or removes the object from the patcher's background layer. background 1 adds the object to the background layer, background 0 removes it. Objects in the background layer are shown behind all objects in the default foreground layer.

color [4 floats]

Sets the color for the object box outline.

fontface [int]

Sets the type style used by the object. The options are:

plain
bold
italic
bold italic

Possible values:

0 = 'regular'
1 = 'bold'
2 = 'italic'
3 = 'bold italic'

fontname [symbol]

Sets the object's font.

fontsize [float]

Sets the object's font size (in points).

Possible values:

'8'
'9'
'10'
'11'
'12'
'13'
'14'
'16'
'18'
'20'
'24'
'30'
'36'
'48'
'64'
'72'

hidden [int] (default: 0)

Toggles whether an object is hidden when the patcher is locked.

hint [symbol]

Sets the text that will be displayed in as a pop-up hint when the user moves the mouse over the object in a locked patcher.

ignoreclick [int] (default: 0)

Toggles whether an object ignores mouse clicks in a locked patcher.

patching_rect [4 floats] (default: 0. 0. 100. 0.)

Sets the position and size of the object in the patcher window.

position [2 floats]

g/s(set)

Sets the object's x and y position in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its size unchanged.

presentation [int] (default: 0)

Sets whether an object belongs to the patcher's presentation.

presentation_rect [4 floats] (default: 0. 0. 0. 0.)

Sets the x and y position and width and height of the object in the patcher's presentation, leaving its patching position unchanged.

rect [4 floats]

g/s(set)

Sets the x and y position and width and height of the object in both patching and presentation modes (if the object belongs to its patcher's presentation).

size [2 floats]

g/s(set)

Sets the object's width and height in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its position unchanged.

textcolor [4 floats]

Sets the color for the object's text in RGBA format.

textjustification [int]

Sets the justification for the object's text.

Possible values:

0 = 'left'
1 = 'center'
2 = 'right'

varname [symbol]

Sets the patcher's scripting name, which can be used to address the object by name in pattr, scripting messages to thispatcher, and the js object.

Multichannel Group Attributes

chans [int]

The chans attribute sets the number of channels and instances in the MC wrapper object. If you want a fixed number of channels regardless of what is connected to the object, you could set chans via a typed-in argument, for example typing mc.cycle~ @chans 100 would create 100 instances of a cycle~ object inside the MC wrapper. If chans is 0, the wrapper object will auto-adapt to the number of channels in its input multichannel signals (using the maximum of all connected signals). For objects without connected multichannel signals, the chans attribute will need to have a non-zero value if you want more than one instance.

If chans is changed while the audio is on, the number of instances will not updated until audio is restarted. However, if chans is reduced while the audio is on, any extra channels will no longer process audio and will output a zero signal.

values [int]

The values attribute only applies to object creation time so it must be set via typed-in argument syntax. values sets the first (and only the first) initial argument for successive instances in the MC wrapper. For example, typing mc.cycle~ @chans 4 @values 50 60 70 80 would assign an initial frequency to the cycle~ instances inside the wrapper. The first instance would be assigned a frequency of 50, the second a frequency of 60, the third 70, and the fourth 80. Note that values does not determine the actual instance count; this can be done using the chans attribute. If there are more instances than elements for the values attribute, those instances are instantiated with the default value.

If you want to set a default initial value for all instances, simply type it as an argument before any typed-in attributes. For example, modifying our example above: mc.cycle~ 100 @chans 10 @values 50 60 70 80. In this example, the first four instances are set as before, but the next six are created with a frequency argument of 100.

To change instance values or attributes after the wrapper object has been created, use the setvalue, applyvalues, or replicatevalues messages.

replicate [int]

When replicate is enabled, input single-channel or multichannel signals containing fewer channels than the number instances in the MC wrapper object are repeated to fill all input channels. For example, when replicate is enabled and you connect a two-channel multichannel signal to the input of an MC wrapper object with four instances, channel 1 of the input will be repeated to channel 3, and channel 2 of the input will be repeated to channel 4. If replicate were disabled, channels 3 and 4 of the input would be set to zero.

target [int]

The target attribute sets a voice index for targeting specific wrapper instances. Subsequent messages are directed to an individual instance instead of all instances. It is strongly recommended you use the more reliable setvalue message instead of the target attribute. The voice index of setvalue will override the current setting of target. When target is 0, incoming messages are sent to all instances. When target is -1, incoming messages do nothing.

usebusymap [int]

When usebusymap is enabled, the MC wrapper controls whether individual instances process audio using a busy map maintained by either an mc.noteallocator~ or mc.voiceallocator~ object. When a channel in the busy map is marked as "free" or "released" no audio processing occurs by any instance on the channel corresponding to the voice index. When usebusymap is disabled, instances in the MC wrapper process audio at all times. This will also be true if usebusymap is enabled and there is no local or named busy map available. (See the busymapname attribute for a description of local and named busy maps).

zero [int]

When the zero attribute is enabled, channels in the MC wrapper due to the use of a busy map output zero signals. To save a small amount of CPU at the risk of loud and unpleasant noises due to uncleared signal data, you can disable zero. In this case, disabled channels in the MC wrapper do nothing to their output channels. If usebusymap is disabled or there is no active local or named busy map available, the setting of the zero attribute has no effect.

Conveniently, when usebusymap is enabled in mc.mixdown~ object, disabled channels are not mixed to the output. When unused signals from wrapped objects with zero disabled feed into mc.mixdown~, they will be ignored, reducing the risk of unpleasantness getting past the mix output.

busymapname [symbol]

When the usebusymap attribute is enabled, an MC wrapper object uses the local busy map of any mc.voiceallocator~ or mc.noteallocator~ in the same patcher by default. To use a named global busy map instead, set the busymapname attribute to the desired name.

Messages

int

Arguments

center-frequency/Q [int]

In middle and right inlets: Integer values are converted to floats and can be sent in the two right inlets to change the center frequency and Q of the filter. By default, the center frequency is expressed in Hz, where the allowable range is from 0 to one quarter of the current sampling rate. If a signal is connected to one of the inlets, a number received in that inlet is ignored. The values are sampled once every signal vector.

float

Arguments

center-frequency/Q [float]

In middle and right inlets: A float can be sent in the two right inlets to change the center frequency and Q of the filter. By default, the center frequency is expressed in Hz, where the allowable range is from 0 to one quarter of the current sampling rate. For convenience, svf~ has two additional input modes that use the more conventional input range, 0 - 1. (see the linear and radians messages). If a signal is connected to one of the inlets, a number received in that inlet is ignored. The values are sampled once every signal vector.

Hz

In either inlet: Sets the frequency input mode to Hz (the default).

clear

Clears the object's sample-memory in case of a blow-up.

linear

In any inlet: Sets the frequency input mode to linear (0 - 1). Linear mode is simply a scaled version of the standard Hz mode, except that values in the 0-1 range traverse the full frequency range.

radians

In any inlet: Sets the frequency input mode to radians (0 - 1). Radians mode lets you set the center frequency directly -- while the input has the same range (0-1), the output has a curved frequency response that is closer to the exponential pitch scale of the human ear.

signal

In left inlet: Signal to be filtered.

In middle inlet: Sets the filter center frequency in Hz.

In right inlet: Sets the bandpass filter "Q" - roughly, the sharpness of the filter - where Q is defined as the filter bandwidth divided by the center frequency. Useful Q values are typically between 0.01 and 500.

Multichannel Group Messages

deviate

Arguments

range [float]
message-name [symbol]
center-value [float]

Generate a random value for each channel around a center value. If no message name is provided then a float message is used by default.

exponential

Arguments

exponent [float]
base [float]

The exponential message generates an exponential series using the second argument as a base and the first argument as an exponent.

scaledexponential

Arguments

exponent [float]
base [float]

The scaledexponential message generates an exponential series using the second argument as a base and the first argument as an exponent. Values are scaled by the instance number, so the total range of the series is independent of the number of channels.

increment

Arguments

increment-amount [float]
message-name [symbol]
start-value [float]

Generate a increasing value for each channel starting at a specified value. If no message name is provided then a float message is used by default.

harmonic

Arguments

multiplier [float]
fundamental [float]

The harmonic message generate a harmonic series using the second argument as the fundamental frequency and the first argument as a multiplier.

subharmonic

Arguments

multiplier [float]
fundamental [float]

The subharmonic message generate a subharmonic series using the second argument as the fundamental frequency and the first argument as a multiplier.