Package MSP

reson~

Resonant bandpass filter

Description

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

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]hz
optional

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

Below is a list of attributes shared by all objects. If you want to change one of these attributes for an object based on the object box, you need to place the word sendbox in front of the attribute name, or use the object's Inspector.

annotation[symbol]

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

background[int]: 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]: 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]: 0

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

jspainterfile[symbol]

JS Painter File

patching_rect[4 floats]: 0. 0. 100. 0.

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

position[2 floats]
write-only

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]: 0

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

presentation_rect[4 floats]: 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]
write-only

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]
write-only

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

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.

Arguments:
  • initial-gain [int]
  • center-frequency [int]
  • Q [int]

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.

Arguments:
  • initial-gain [float]
  • center-frequency [float]
  • Q [float]

list

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.

Arguments:
  • initial-gain [number]
  • center-frequency [number]
  • Q [number]

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
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