Parametric Equalizer
Purpose
The Parametric Equalizer is available in a variety of sizes ranging from a single band up to 32 bands. Parametric Equalizers may be wired in series if you desire more bands. A multi-band Parametric consumes less DSP resources than the equivalent series connection of single band Parametric Equalizers.
We recommend the use of Parametric Equalizers for most equalization applications as they provide the most flexibility and are efficient.
Controls
Band Bypass
Bypasses a single parametric EQ band. Setting a Band's Level control to +0dB has the same effect as engaging Band Bypass.
Band Overload
Lights when clipping occurs in an EQ band. The device overload indicator will also light when any band clips. Clipping is only possible if the band's Level control is set above +0dB.
Bandwidth
The Bandwidth control adjusts the frequency range over which the band is affective. Bandwidth is measured in octaves; a Bandwidth setting of "1" results in a filter response with 3dB down points 1 octave apart. On a logarithmic scale, the response is centered about the Center Frequency setting.
Center Frequency
The Center Frequency control adjusts the frequency about which the EQ band is centered.
Device Bypass
The Device Bypass button bypasses all bands of the parametric equalizer device.
Device Overload
Lights when clipping occurs in any EQ band. Clipping is only possible if a Level control is set above +0dB.
Level
Adjusts the amount of boost or cut provided by the EQ band.
Note: It is possible to create an overload condition within the EQ band if this control is set above +0dB. Such an overload will be indicated by both the Band Overload and the Device Overload indicators.
Notch
Changes the lower limit of the range of the Level controls. When On, the levels can go down to -80dB. When Off, the Level controls only go down to -18dB.
Symmetric
When enabled, gives each parametric band a Frequency Response similar to that of a Graphic Equalizer band. A Graphic Equalizer band has a cut response which is the exact mirror of its boost response. The cut response of a parametric EQ is naturally narrower than its boost response.
Graphical Frequency Response
Displays the frequency response of the filter. See the EQ Curve Graphics Display documentation for a complete description.
Parametric Equalizer Frequency Response
Magnitude Response with Symmetry control Off, Center frequency 1000Hz, Gain +12dB (Red) and -12dB (Blue), Bandwidth 0.64.
Magnitude Response with Symmetry control On, Center frequency 1000Hz, Gain +12dB (Red) and -12dB (Blue), Bandwidth 0.64.
Parametric Equalizer Schematic
Schematic for 2 band Parametric Equalizer
Advanced Topic
The number of bands in the Parametric is determined by an argument in the Algorithm String. The Algorithm String has the following form.
PARAMEQ N
Where N is the number of filter bands. The legal range is 1 to 32.
Example
"PARAMEQ 13" creates a 13 band Parametric Equalizer Algorithm.