The Filter Toolbox enhancement allows you to define your own audio filters.    
The following setting options are available:
Check box
User Drawn Filter Response
Activates the option for changing the graph using handles.
User Drawn Filter Response
Allows you to define a filter yourself by means of adjustable curves.
Switches between a linear and logarithmic scale for the limiting frequency graphic.
The following setting options are available in the Bandpass Filter area:
Check box
Bandpass Filter
Adds a bandpass filter that allows a certain frequency range to be exceeded.
Upper Limit
Specifies the upper frequency limit for the bandpass filter.
Lower Limit
Specifies the lower frequency limit for the bandpass filter.
The following check boxes are available in the Notch Filters area:
Insert up to three notch filters and bandpass stops that prevent a particular frequency range from being exceeded. You can specify the frequency of each notch filter by sliders.

Filter Toolbox