Equaliser Selection

Equaliser Selector

The Equaliser panel is used to select the type of equaliser whose responses REW is to model. Changing the equaliser type updates the filter panel, applying the settings appropriate to the selected equaliser. Filters already defined are retained where possible, but parameter values will be adjusted if necessary to comply with the ranges and resolutions of the chosen equaliser. The currently selected equaliser is shown in the panel title and in the EQ Filters panel.

TMREQ
The TMREQ Equaliser offers the full range of filters and filter settings supported by TMREQ (peaking = parametric, low pass, high pass, low shelf, high shelf and notch). For the Peaking filters the bandwidth in Hz between the half gain points is given by:

Bandwidth = centre frequency/Q

The TMREQ setting allows 8 filters. The adjustment ranges are:

ParameterMinimumMaximumResolution
Frequency20200001Hz
Gain-15+60.1dB
Q0.1500.1
BFD Pro DSP1124P
The DSP1124P Equaliser supports the DSP1124P's parametric filters, allowing 12 filters. The adjustment ranges are:

ParameterMinimumMaximumResolution
Frequency2020000see below
Gain-48+161dB
BW/6011201

The frequency control adjusts in the pseudo-1/60th octave steps DSP1124P supports (20 evenly spaced subdivisions of the ISO one-third octave intervals), with the one-third octave and fine adjustment values DSP1124P uses shown alongside the actual frequency in the EQ Filters Panel.

The "BW/60" control replicates the effect of the DSP1124P's bandwidth setting. This control sets the bandwidth of the filter between the half-gain points with:

Bandwidth (Hz) = centre frequency*(BW/60)*sqrt(2)

For example, at a bandwidth setting of 60/60 a filter centred on 1kHz with a gain of -6dB will have a bandwidth of 1,414Hz between the points where its response crosses -3dB. This bandwidth remains constant as the filter's gain is adjusted (Note that the Behringer DSP1100 software package does NOT correctly reproduce the way the bandwidth control actually operates, its bandwidths are too small by a factor of sqrt(2)).

Defining filter bandwidth in this way is not uncommon (the TMREQ filters use a similar definition). The relationship between Q and BW for the DSP1124P is

Q = 60/[(BW/60)*sqrt(2)]


so the bandwidth range of 1/60 to 120/60 gives a Q range from 42.4 to 0.35.
BFD Pro FBQ2496
The FBQ2496 Equaliser supports the FBQ2496's parametric filters, allowing 20 filters. The adjustment ranges are:

ParameterMinimumMaximumResolution
Frequency20200001/60th octave
Gain-36+150.5dB (1dB below -15dB)
Bandwidth1/6010octaves, see below

The frequency control adjusts in approximately 1/60th octave steps (more precisely, 1/200th of a decade).

The bandwidth control adjusts in 1/60 of an octave steps from 1/60 to 5/60 of an octave, then goes through 1/10, 1/9, 1/8, 1/7, 1/6, 1/5, 1/4, 1/3, 1/2, 3/4, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 10 octaves.

The relationship between Q and BW in octaves for the FBQ2496 is

Q = sqrt(2)/BW


so the bandwidth range of 1/60 to 10 octaves gives a Q range from 84.85 to 0.14.
DCX2496
The DCX2496 Equaliser supports parametric filters (labelled "BP" for Band Pass) and low and high shelving filters (with 6 and 12dB/octave slopes). It allows up to 9 filters per channel, depending on the other processing the unit is doing. The parametric filter bandwidth in Hz between the half gain points is given by:

Bandwidth = sqrt(gain)*centre frequency/Q

The adjustment ranges are:

ParameterMinimumMaximumResolution
Frequency2020000106 steps per decade
Gain-15+150.1dB
Q0.11020 steps per decade
The frequency control adjusts in steps of 1/106th of a decade. The Q control adjusts in steps of 1/20th of a decade, i.e. there are 20 Q values between 0.1 and 1 and another 20 between 1.0 and 10.
SMS-1
The SMS-1 Equaliser supports parametric filters only, allowing 8 filters. The filter bandwidth in Hz between the half gain points is given by:

Bandwidth = centre frequency/Q

N.B. The SMS-1 filter shapes have not been verified against an actual unit.

The adjustment ranges are:

ParameterMinimumMaximumResolution
Frequency151201Hz
Gain-13+60.5dB
Q0.320.00.1
R-DES
The R-DES Equaliser supports parametric filters only, allowing 5 filters. The filter bandwidth in Hz between the half gain points is given by:

Bandwidth = 1.766*centre frequency/Q

N.B. The R-DES filter shapes have not been verified against an actual unit.

The adjustment ranges are:

ParameterMinimumMaximumResolution
Frequency201201Hz
Gain-10+100.1dB
Q1150.1
QSC DSP-30
The DSP-30 Equaliser supports parametric filters only, allowing 10 filters. The filter bandwidth in Hz between the half gain points is given by:

Bandwidth = centre frequency/Q

N.B. The DSP-30 filter shapes have not been verified against an actual unit.

The adjustment ranges are:

ParameterMinimumMaximumResolution
Frequency20200000.1Hz
Gain-120+120.1dB
Q0.3500.1
Crown USM-810
The USM-810 Equaliser supports parametric filters only, allowing 10 filters. The filter bandwidth in Hz between the half gain points is given by:

Bandwidth = sqrt(gain)*centre frequency/Q

N.B. The USM-810 filter shapes have not been verified against an actual unit.

The adjustment ranges are:

ParameterMinimumMaximumResolution
Frequency20200001Hz
Gain-24+240.1dB
Q0.1350.01
Generic
The Generic Equaliser supports a full range of filters and filter settings (peaking = parametric, low pass, high pass, low shelf, high shelf and notch). For the Peaking filters the bandwidth in Hz between the half gain points is given by:

Bandwidth = centre frequency/Q

The Generic setting allows 20 filters. The adjustment ranges are:

ParameterMinimumMaximumResolution
Frequency10220000.01Hz below 100Hz, 0.1Hz below 1kHz, 1Hz above 1kHz
Gain-120+300.1dB
Q0.1500.01
MiniDSP
The MiniDSP Equaliser supports the same filter types and resolutions as the Generic setting, but for 6 filters. It is aimed at the MiniDSP plug-in Advanced mode, which allows filters to be specified by their biquad coefficients. The Send Filter Settings to Equaliser action writes the filter coefficients to a file in a format suitable for use with the MiniDSP software (note that the a1 and a2 coefficients are negated per the MiniDSP format). An advantage of this is the very high filter frequency and Q resolution it allows, permitting exact targeting of modal resonances. The MiniDSP plug-in has an Import REW File button on its Parametric EQ configuration screens to load the files.

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