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lores~

Resonant lowpass filter

Description

lores~ implements an inexpensive lowpass with an adjustment that lets you add a specified resonance. The middle inlet sets a kind of cutoff frequency, but the sharpness of the filter depends on the resonance passed in through the right inlet (0 is a little bit sharp and 1 as sharp as possible).

Arguments

Name Type Opt Description
initial-cutoff-frequency and response (ints or floats) list opt Numbers set the initial cutoff frequency and resonance. The default values for both are 0. If a signal is connected to the middle or right inlet, the argument corresponding to that inlet is ignored.

Messages

int cutoff-frequency/resonance [int]
 An int or float can be sent in the middle or right inlets to change the cutoff frequency or resonance. If a signal is connected one of the inlets, a number received in that inlet is ignored.
float cutoff-frequency/resonance [float]
 An int or float can be sent in the middle or right inlets to change the cutoff frequency or resonance. If a signal is connected one of the inlets, a number received in that inlet is ignored.
clear Clears the filter's memory. Since lores~ is a recursive filter, this message may be necessary to recover from blowups.
signal In left inlet: Any signal to be filtered.

In middle inlet: Sets the lowpass filter cutoff frequency.

In right inlet: Sets a "resonance factor" between 0(minimum resonance) and 1(maximum resonance). Values very close to 1 may produce clipping with certain types of input signals.

Information for box attributes common to all objects

Output

signal: The filtered input signal. The equation of the filter is

yn = scale * xn - c1 * yn-1 + c2 * yn-2

where scale, c1, and c2 are parameters calculated from the cutoff frequency and resonance factor.

Examples

Specify cutoff frequency and resonance of lowpass filter

See Also

Name Description
biquad~ Two-pole, two-zero filter
buffir~ buffer-based FIR filter
comb~ Comb filter
filtergraph~ Graphical filter editor
onepole~ Single-pole lowpass filter
reson~ Resonant bandpass filter