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reson~ Reference

Resonant bandpass filter

reson~

Description

Use the reson~ object when you need a resonant bandpass filter.

Examples

Control gain, center frequency, and Q of a bandpass filter to alter a rich signal

Discussion

reson~ implements the following filter equation:

y[n] = a0 * (x[n] - r * x[n-2]) + b1 * y[n-1] + b2 * y[n-2]
where r, b1, and b2 are parameters calculated from the input center frequency cf and Q.

Q = cf/bandwidth.

Inputs can be floats or signals.

Arguments

initial-gain [float]

Optional

Sets the initial gain. The default value is 0.

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.

Attributes

cf [float]

The center frequency for the filter, in hertz.

gain [float]

Sets the bandpass filter gain. This value should generally be less than 1.

q [float]

Sets the bandpass filter resonance, or "Q." Roughly, this is the sharpness of the filter, where Q is defined by the center-frequency divided by the filter-bandwidth. Useful Q values are typically between 0.01 and 500.

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.

jspainterfile [symbol]

JS Painter File

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.

Messages

int

Arguments

initial-gain [int]
center-frequency [int]
Q [int]
An int can be sent in the three right inlets to change the filter-gain, center-frequency, and Q. If a signal is connected to one of the inlets, a number received in that inlet is ignored.

float

Arguments

initial-gain [float]
center-frequency [float]
Q [float]
float can be sent in the three right inlets to change the filter-gain, center-frequency, and Q. If a signal is connected to one of the inlets, a number received in that inlet is ignored.

list

Arguments

initial-gain [number]
center-frequency [number]
Q [number]
In left inlet: The first number sets the filter-gain. The second number sets the filter center-frequency. The third number sets the filter-Q. If any of the inlets corresponding to these parameters have signals connected, the corresponding value in the list is ignored.

clear

Clears the filter's memory. Since reson~ is a recursive filter, this message may be necessary to recover from blowups.

signal

In left inlet: Any signal to be filtered.

In left-middle inlet: Sets the bandpass filter gain. This value should generally be less than 1.

In right-middle inlet: Sets the bandpass filter center frequency in hertz.

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

Output

signal

The filtered input signal.

See Also

Name Description
Sound Processing Techniques Sound Processing Techniques
biquad~ Two-pole, two-zero filter
comb~ Apply a comb filter effect
cross~ Third-order crossover filter
onepole~ Single-pole lowpass filter
lores~ Resonant lowpass filter
reson~ Resonant bandpass filter
svf~ State-variable filter with simultaneous outputs
Audio Filtering Audio Filtering