Equalizer

An equalizer changes the frequency response of a signal so it has different tonal qualities.

After you select Effects menu -> Equalizer you will see a dialog containing three different Equalizer representations. Use the tabs at the top to select between the Visual Equalizer, Graphic and Parametric Equalizer views.

Visual Equalizer

Left click on any point to create a new band point. To remove a band point right click on it. To assist you with shaping the Equalizer graph in the way you want, there is a preset list that displays the most common sorts of filters used in the Equalizer graph. You can choose any preset filter from the list and then manipulate the filter to achieve the effect you desire. The list of filters to choose from and how you can shape them are explained below. Note that all fields where a frequency value is entered can have a maximum value of 20000 (Hertz).

Graphic Equalizer

The Graphic Equalizer uses discrete sliders to set the gain or attenuation of a signal at a particular frequency. You can select how many sliders you would like to manipulate by entering a value between 3 and 20 in the box at the top of the display. When you change the number of sliders you would like to utilize, the frequencies are automatically allocated to best span the audible frequency range from 20Hz to 20kHz. Selecting presets allows you to easily configure common filters such as low pass or high pass. Note that when you change the Graphic Equalizer, the Visual and Parametric Equalizer views are not changed, as the changes in the three views are not compatible.

Parametric Equalizer

The Parametric Equalizer is similar to the Graphic Equalizer, but with more control. Here you can adjust the frequency and bandwidth of the individual sliders by left clicking on the frequency or Q values below each slider. Frequency must be set between 20Hz and 20,000 Hz. The Q parameter must be set between 0.05 and 20. A higher Q causes the gain or attenuation peak at the frequency to be much sharper, and therefore less likely to impact adjacent frequency content, while a lower Q applies the modification more smoothly across the frequency spectrum.

Band Pass Filter
Keeps only those frequencies in the audio between a certain range.
Start Frequency
The lower cutoff frequency value, in Hertz.
End Frequency
The upper cutoff frequency value, in Hertz.
Slope Length
The width of the slope extending from the lower and upper cutoff points, in Hertz.
Amplitude
The degree that the frequencies outside the cutoff range are suppressed. 6dB means the volume is reduced to one-half, 12dB means the volume is reduced to one-quarter. Maximum value is 60dB.
Band Stop/Cut Filter
Keeps all frequencies in the audio except those between a certain range.
Start Frequency
The lower stop frequency, in Hertz.
End Frequency
The upper stop frequency, in Hertz.
Slope Length
The width of the slope extending from the lower and upper stop points, in Hertz.
Rejection
The degree that the frequencies inside the stop range are suppressed. 6dB means the volume is reduced to one-half, 12dB means the volume is reduced to one-quarter. Maximum value is 60dB.
High Pass Filter
Keeps only those frequencies in the audio above a certain value.
Pass Frequency
The point at which all frequencies above are to be kept, in Hertz.
Slope Length
The width of the slope extending from the pass frequency, in Hertz.
Low Pass Filter
Keeps only those frequencies in the audio below a certain value.
Pass Frequency
The point at which all frequencies below are to be kept, in Hertz.
Slope Length
The width of the slope extending from the pass frequency, in Hertz.
Notch Filter
Attenuates the frequencies in the specified range to very low levels and passes all other frequencies unaltered. There is no slope - frequencies are either attenuated or not.
Start Frequency
The lower cutoff frequency value, in Hertz.
End Frequency
The upper cutoff frequency value, in Hertz.
Boost Filter
Either attenuates or boosts frequencies in the specified range and passes all others unaltered.
Start Frequency
The lower boost/cut frequency value, in Hertz.
End Frequency
The upper boost/cut frequency value, in Hertz.
Slope Length
The width of the slope extending from the lower and upper boost/cut points, in Hertz.
Amplitude
The degree that the frequencies inside the boost/cut range are either boosted or cut. 6dB means the volume is boosted to twice the original amount, and 12dB means the volume is is boosted to four times the original amount. 20dB.
High Pass Shelf Filter
Attenuates signals of frequencies below the cut frequency and passes all others unaltered.
Start Frequency
The lower cut frequency value, in Hertz.
Slope
The width of the slope extending from the lower and upper cut points, in Hertz.
Rejection
The degree that the frequencies inside the cut range are cut. 6dB means the volume is attenuated to about half the original level, and 12dB means the volume is attenuated to about a quarter of the original level.
Low Pass Shelf Filter
Attenuates signals of frequencies above the cut frequency and passes all others unaltered.
Start Frequency
The lower cut frequency value, in Hertz.
Slope
The width of the slope extending from the lower and upper cut points, in Hertz.
Rejection
The degree that the frequencies inside the cut range are cut. 6dB means the volume is attenuated to about half the original level, and 12dB means the volume is attenuated to about a quarter of the original level.

If you are using the equalizer simply to drop lower frequencies, you should always try the High Pass filter first (Effects menu -> High Pass Filter), because it is better and faster for very low frequencies.