The EQ Filters panel is displayed by clicking its button at the top of
the EQ window.
The panel shows the filters settings for the current measurement.
Buttons at the top of the panel allow the filter settings
to be sorted, loaded, saved or deleted and the sort direction and key to
be specified. At the right of the panel is a figure for the headroom the
filter set requires, this will only be greater than zero if the filter set
has overall gain. The equaliser type can be changed in the
Equaliser selector at the right of the EQ window.
Each filter has:
- A check box to select/deselect it
- An identifying number and coloured line showing how the filter
will be displayed when showing individual filter responses
- A "Control" setting which should be set to "Automatic" for
filters REW is allowed to configure or "Manual" for filters it
must leave unaltered.
- A "Type", which for TMREQ and Generic filters can be:
The Generic and DCX2496 also have shelving filters implemented per the DCX2496
- PK for a peaking (parametric) filter
- LP for a 12dB/octave Low Pass filter (Q = 0.7071)
- HP for a 12dB/octave High Pass filter (Q = 0.7071)
- LS for a Low Shelf filter (S = 0.9)
- HS for a High Shelf filter (S = 0.9)
- NO for a notch filter
- Modal for a Modal filter
The Generic equaliser setting also has
- LS 6dB for a 6dB/octave Low Shelf filter (S = 0.5)
- HS 6dB for a 6dB/octave High Shelf filter (S = 0.5)
- LS 12dB for a 12dB/octave Low Shelf filter (S = 1.0)
- HS 12dB for a 12dB/octave High Shelf filter (S = 1.0)
For most other equalisers the only types available are PK and Modal,
although the labelling for the PK filter varies. The miniDSP equaliser
setting supports all the filter types that Generic supports.
- LPQ, a 12dB/octave Low Pass filter with adjustable Q
- HPQ, a 12dB/octave High Pass filter with adjustable Q
- Centre Frequency/Corner Frequency, Gain and either Q, Bandwidth or Target T60
controls as appropriate for the filter type and selected
equaliser. The filter bandwidth in
Hz at the half-gain points is shown alongside the Q or Bandwidth
control for PK filters.
- Displays of the 60dB decay time in milliseconds for a mode the
current filter settings would match and the 60dB decay time of the
filter itself, which is the decay which would remain after cancelling
the decay of a modal resonance of the indicated modal decay. These
correspond to the locations of the zeroes and poles of the filter.
The DSP1124P mode has an additional display showing frequency in the form
in which is must be entered on that unit, i.e. as a one-third octave centre
and a fine adjustment which ranges from -9 to +10 (63 -5 in the example below).
The Modal filter type is a peaking filter whose bandwidth or Q is adjusted
by REW to match a Target T60 time, it is used to accurately counter a modal
resonance whose T60 time is known. To match a specific T60 time the filter's
bandwidth or Q must be altered as its gain or centre frequency change. REW
chooses the bandwidth or Q setting supported by the selected equaliser that
most closely matches the target T60.