Rane RPM 26 - Manual (Page 15)

Manual-15
EXTENDED PARAMETRIC (PEQ+)
Some DSP Programs provide “Extended”
Parametric EQ, abbreviated PEQ+. Extended
parametric simply means that two of the available
PEQ filters contain extended capabilities. These
two special PEQ filters support various EQ filter
types, such as high pass (
HP) or low pass (LP)
Linkwitz-Riley, Butterworth or Bessel filters, these are
abbreviated
LR, BW and Bsl, respectively. Different slopes
for each of these filter types are also available, allowing 12
dB/Oct., 18 dB/Oct. and 24 dB/Oct. filter implementations
(2 nd , 3 rd or 4 th order), where applicable. In any extended
parametric, only the first and last filters contain the extended
capabilities; 1 and 8, in the above example screen.
The purpose of Extended Parametric is to give the RPM
26 the capability to implement up to a 6-way crossover. Since
each PEQ+ output can implement any crossover frequency
range, treating each output as its own crossover band,
provides multi-way crossovers.
Hint: For midband crossovers, use 2 bands with one set
for LP, the other set for HP and overlap them.
Note: Operation of Extended Parametrics (PEQ+) is
exactly like regular parametrics (PEQ), the only difference is
when you choose
Cut, LR, BW or Bsl filter types for a given
filter, the Level and BW(Q) settings for that filter have no
effect and are ignored by RaneWare. The Shelving filter type
also ignores the BW(Q) setting.
COMPRESSOR
Most DSP Programs provide a program
compressor on each input. The compressor’s
purpose is to alter the dynamic range of the
incoming signal. Compressors are simply fancy
volume controls. Only the volume level is
altered by compression. When compression
occurs, the compressor turns the volume down in a tightly
controlled manner. The
Threshold is a voltage level setting
above which compression (or turning down the volume)
occurs. The
Ratio tells the compressor how much to turn the
volume down for a given increase above the Threshold. The
Attack time dictates how quickly the signal reaches a
“settled” compression level for a given input signal step size.
The
Release time dictates how long it takes the output signal
to reach a “settled” level after the input signal is reduced.
filter. (See the EXTENDED
PARAMETRIC section below
for additional filter types such as
Linkwitz-Riley, Bessel and
Butterworth filters.) Those
systems that require constant
directivity horn equalization can
use the
High Shelf PEQ Filter
Type in combination with other
PEQ filters to achieve the
appropriate EQ for the combina-
tion of horn and compresssion
driver you are using. For
optimum frequency response, use
an analyzer to achieve the best
possible horn EQ compensation.
The bandwidth, abbreviated BW(Q), for each parametric
EQ filter is edited with the horizontal scroll bar. There are 80
steps between a Q of 40 and 0.5. This is a bandwidth of
between 0.036 and 2.543 octaves respectively. The horizontal
scroll bar adjusts the bandwidth control in three ways.
Clicking the left or right arrows adjusts the bandwidth one
step at a time (one step is a
BW(Q) change of 0.025 octaves).
Clicking between the arrows and the sliding box (Thumb)
adjusts the bandwidth steps 0.25 octaves at a time. Clicking
and holding the Thumb allows you to drag the control.
A Bypass check box appears on the bottom right allowing
the selected PEQ filter to be bypassed. This is essentially
equivalent to setting that filter’s level to zero. This is useful
when comparing the effect of a single PEQ filter’s frequency
response contribution. A small red ‘
X ’ appears over the top of
the circled filter number to indicate that the filter is bypassed.
(See filter #4 on the example screen to the left.) The bypassed
filter’s response graph does not change on the parametric
graph, but it does on the
Overall Response graph (double-
click on the Output’s screw terminal). The Overall Response
curve also shows the contributions of the crossover and the
high/low cut filters (if applicable). See the OVERALL
RESPONSE section on page Manual-19 for further details.
A right mouse click on the parametric detail window pops
up a menu allowing flattening of the current ( Flatten Filter
Level) or all PEQ filters (Flatten All Filter Levels). This same
right mouse click menu allows bypassing all PEQ filters (
All
Filters Bypassed) for conveniently comparing equalized and
unequalized settings.
You can also Copy (select Copy) and Paste (after
Copying) the PEQ settings from one PEQ to another from
this menu. The PEQ copy and paste scheme allows you to
copy, for example, the first three PEQ bands from a 6 band
parametric into a 3 band PEQ. The three extra bands, 4, 5 & 6
in this case, are simply ignored by the 3 band PEQ. The same
goes for pasting from a 3 band into a 6 band PEQ. Only the
first three bands’ settings will be copied into the 6 band PEQ
and bands 4, 5 and 6 will be unchanged after the paste.
This makes it easy to set up one processing block, then
copy settings to other blocks.