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Block Reference

Parametric EQ Filter

Functionality

The Parametric EQ block (PEQ) provides a low-cut and high-cut filter, and up to 15 parametric bell filters. The 2nd-order Butterworth high-cut and low-cut filters are useful for band-limiting audio to a specific frequency range. Each parametric filter is a bandpass type with equal response on either side of the center frequency. It can be used as a notch filter with high-Q settings (narrow BW) for feedback elimination, with low-Q (wide BW) settings for broadband EQ, or anything in between. Parametric filters provide from +12 dB of boost to -15 dB of cut, with an adjustable center frequency (20 Hz – 20 kHz) and bandwidth (0.015- 4 Octaves). All filters have a bypass control to disable the filter’s effect on the frequency response of the block.

How to Use
Adding the Block to Your System
  1. Click the Processing tab to open the Processing Workspace.
  2. In the palette area, click the DSP tab.
  3. Expand the Filters category of blocks.
  4. Click and drag the Parametric EQ block into your Processing Map.
  5. Wire it into your system in the appropriate location.
  6. (Optional) Customize the names of the block and the input and output node by clicking their current name and then typing the custom name in the text box that appears. Click the X to save the name.
Configuring the Block
  • Open the Parametric EQ block's properties by double-clicking the block or hovering and clicking the properties icon that appears in the upper right of the block's title bar. From here, you can do the following:
    • Select a filter. By default, the block contains one parametric bell filter (you can add more), a high-cut filter, and a low-cut filter. There are three ways to select a filter: click its frequency/gain or bandwidth handle in the graph, select it from the dropdown list in the View box (upper right), or select it in the table view (bottom).
    • Add or remove a bell filter. You can add up to 14 more bell filters (for a total of 15) by clicking the Add Filter button. To remove a bell filter, select it and then click the Remove Filter button.
    • After selecting a filter, use the Frequency, Gain, Bandwidth, and Bypass controls to configure the frequency response of the filter. Gain and Bandwidth controls are only available for the bell filters.
      • You can use the green/brown gain/frequency handles and the purple bandwidth handles on the graph to control a bell filter's gain/frequency and bandwidth at any time.
      • You can use the brown frequency handles on the graph to control a Cut filter's corner frequency at any time.
      • tip: If you are using the Parametric EQ block to manage the frequency response of a space with multiple uses, you may find it necessary to save its settings in a preset and then recall different presets as the space changes. Once you’ve got a set of EQ settings stored in a preset, reconfigure your room for its next use and click the Flatten All button to quickly return to a flat frequency response.

      • You can bypass any filter by selecting its Bypass checkbox. Bypassing a filter effectively turns that filter into a wire.
      • note: A bypassed filter’s Frequency/Gain and Bandwidth responses and handles are hidden in the graph. By default the graph only displays the composite magnitude response (the total result of every filter in the block).

    • To view the individual contribution of a selected filter, check the Individual button in the View box in the upper right corner of the dialog box. You can also display the individual and composite phase response by checking the Phase checkbox.

 

User Interface Elements
Parametric EQ Block

Parametric EQ Block

UI Element Purpose
Input node Connection point for wiring input to the Parametric EQ block
Output node Connection point for wiring the Parametric EQ output to another block
x 1 Indicates the total number of Parametric EQ filters in the block

 

Parametric EQ Block Properties

(Hover over the thumbnail below to view the properties dialog box.)

Parametric EQ Block Properties

 
UI Element Purpose

Response graph

Graphical representation of filters. Use the green/brown handles to adjust a filter's gain and frequency, and the purple handles to adjust a filter's bandwidth. Gain and Bandwidth controls are only available for bell filters. Use View options to change graph content.
View options Selecting Magnitude (selected by default) displays the filters' Magnitude on the graph. Selecting Phase (deselected by default) displays the filters' phase response on the graph. Selecting Composite (selected by default) displays frequency/gain handles for all filters on the graph. Selecting Individual (deselected by default) displays the individual contribution of the selected filter.
Add Filter/Remove Filter Click to add/remove the selected bell filter from the graph.
Flatten All Click to return to a flat frequency response.
Frequency control Displays the current frequency of the selected filter. Change the frequency by moving the slider or editing the frequency value in the edit box.
Gain control Displays the current gain of the selected filter. Change the gain by moving the slider or editing the gain value in the edit box.
Bandwidth control Displays the current bandwidth of the selected filter. Change the gain by moving the slider or editing the gain value in the edit box.
Bypass (above Table View) Selecting this checkbox bypasses the selected filter, which effectively turns the filter into a wire.
Filter Table View Displays the Frequency, Gain, and Bandwidth for each parametric filter. Displays the Frequency, Type, and Slope/Order for each cut filter.To select a filter, click its row in the table. You can also bypass a filter by selecting its associated Bypass checkbox. You can show or hide this table view by clicking the Show/Hide arrow above the table.
Bypass All Selecting this checkbox bypasses all filters.