A newer version of Max is available. Click here to access the latest version of the documentation

lores~ Reference

Resonant lowpass filter

lores~

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).

Examples

Specify cutoff frequency and resonance of lowpass filter

Arguments

cutoff [number]

Optional

A number sets the initial cutoff frequency. The default value is 0. If a signal is connected to the inlet, the argument corresponding to the inlet is ignored.

resonance [number]

Optional

A number sets the filter resonance. The default value is 0. If a signal is connected to the inlet, the argument corresponding to the inlet is ignored. A resonance of 0 is a little bit sharp and 1 is as sharp as possible.

Attributes

cutoff [float]

Sets the initial cutoff frequency.

resonance [float]

Sets the filter resonance. A resonance of 0 is a little bit sharp and 1 is as sharp as possible.

Common Box Attributes

Messages

int

Arguments

cutoff-frequency/resonance [int]
An int 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. A resonance of 0 is a little bit sharp and 1 is as sharp as possible.

float

Arguments

cutoff-frequency/resonance [float]
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. A resonance of 0 is a little bit sharp and 1 is as sharp as possible.

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.

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.

See Also

Name Description
Sound Processing Techniques Sound Processing Techniques
biquad~
buffir~
comb~
cross~
onepole~
svf~
reson~
Audio Filtering Audio Filtering