Boost or cut treble (upper) frequencies of the audio using a two-pole shelving filter with a response similar to that of a standard hi-fi’s tone-controls. This is also known as shelving equalisation (EQ).
The filter accepts the following options:
- gain, g
-
Give the gain at whichever is the lower of ~22 kHz and the Nyquist frequency. Its useful range is about -20 (for a large cut) to +20 (for a large boost). Beware of clipping when using a positive gain.
- frequency, f
-
Set the filter’s central frequency and so can be used to extend or reduce the frequency range to be boosted or cut. The default value is
3000Hz. - width_type, t
-
Set method to specify band-width of filter.
- h
-
Hz
- q
-
Q-Factor
- o
-
octave
- s
-
slope
- k
-
kHz
- width, w
-
Determine how steep is the filter’s shelf transition.
- mix, m
-
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
- channels, c
-
Specify which channels to filter, by default all available are filtered.
Commands
This filter supports the following commands:
- frequency, f
-
Change treble frequency. Syntax for the command is : "frequency"
- width_type, t
-
Change treble width_type. Syntax for the command is : "width_type"
- width, w
-
Change treble width. Syntax for the command is : "width"
- gain, g
-
Change treble gain. Syntax for the command is : "gain"
- mix, m
-
Change treble mix. Syntax for the command is : "mix"