lowpass

Apply a low-pass filter with 3dB point frequency. The filter can be either single-pole or double-pole (the default). The filter roll off at 6dB per pole per octave (20dB per pole per decade).

The filter accepts the following options:

'frequency, f'

Set frequency in Hz. Default is 500.

'poles, p'

Set number of poles. Default is 2.

'width_type, t'

Set method to specify band-width of filter.

'h'

Hz

'q'

Q-Factor

'o'

octave

's'

slope

'k'

kHz

'width, w'

Specify the band-width of a filter in width_type units. Applies only to double-pole filter. The default is 0.707q and gives a Butterworth response.

'channels, c'

Specify which channels to filter, by default all available are filtered.

Command line examples

• Lowpass only LFE channel, it LFE is not present it does nothing:

  lowpass=c=LFE
  

Commands

This filter supports the following commands:

'frequency, f'

Change lowpass frequency. Syntax for the command is : "frequency"

'width_type, t'

Change lowpass width_type. Syntax for the command is : "width_type"

'width, w'

Change lowpass width. Syntax for the command is : "width"