Rane RPM 26i - Manual (Page 18)

Manual-18
FINE DELAY
The Fine Delay block has 20 microsecond
(0.02 msec) minimum delay steps and is
intended to allow individual driver alignment
in speaker stacks or for lobe steering. Twenty
microseconds is approximately 0.02 feet
(about ¼") or 0.00635 meters (which gets
rounded to 0.01 meters in the RPM 26i).
The Fine Delay block and Fine Delay detail window are
shown to the right. Like the Coarse Delay block, the Fine
Delay block provides up and down arrows for incrementing
and decrementing, however the Fine Delay has 20 microsec-
ond steps that are always displayed as 0.02 milliseconds. The
Fine Delay detail window provides three ways to edit the
delay value; single steps by clicking the left and right arrows,
0.20 millisecond steps by clicking between the Thumb and
the arrows or clicking and dragging the Thumb itself. Click
directly in the edit box to display the cursor and type in a new
value.
The Global Settings for Delay Units (milliseconds, feet
and meters) and Temperature are displayed in both the
Coarse and Fine detail windows. These are global settings,
meaning that once changed, the changes appear throughout
the RPM 26i. To change all displayed delay settings to
different units, click the down arrow in any
Delay Units
selection box and select the new units from the list. Edit the
Temperature by clicking the up or down arrows or click
directly in the edit box to display the cursor and type in a new
Temperature. Click one of the radio buttons to display the
Temperature in either ‘F’ for Fahrenheit or ‘C’ for Celsius.
Only when distance units (feet or meters) are used does
the Temperature setting impact the displayed units. The
Temperature is calculated with dry air for the displayed
distances. The RPM 26i does not alter the delay time when
the
Delay Units are changed, only the way the delay is
displayed is altered. Also, even though the displayed values
may be in feet or meters, clicking the scroll bars and arrows
still changes the delay times in milliseconds (1 msec. for
Coarse Delay and 0.02 msec. for Fine Delay).
The Link selection box in the Fine Delay detail window,
“ties” groups of Fine Delays together. Select the down arrow
to the right of the selection box to assign
Link groups. There
are 4 possibilities, None, 1, 2 or 3. None in the selection box
indicates the given delay is tied with no other delay. If two
delays’
Link boxes
share a common value,
for example,
2, then
those two delays are
Linked together. When
Linked, the selection
box’s number—
1, 2 or
3—also appears in red
in the Fine Delay block
on the Device Edit
Screen. This indicates
which
Link group a
given delay block is in
without needing to
open the detail window.
CROSSOVERS
Both 2- and 3-way crossover blocks are
found in various DSP Programs in the RPM.
Up to a mono 6-way crossover can be
implemented with the RPM 26i’s powerful
Extended Parametric EQ, see the Extended
Parametric (PEQ+) section on pages
Manual-15-16 for details on implementing
more than a 3-way crossover. The 2- and 3-
way crossover interfaces are similar. Only the
3-way is covered here. The 2-way interface
simply removes one band. The 3-way
crossover block is shown at the right.
The current crossover frequency settings
are shown on this block, making it unneces-
sary to open the detail window to check the
crossover’s current frequency settings. The
high frequency output of the crossover block
is graphically always on top with the lowest frequency
outputs displayed on the bottom.
Double-clicking on the Crossover block brings up the
Crossover detail window shown at the bottom of the follow-
ing page. The graph displays the calculated frequency
response of the RPM 26i Outputs. For viewing ease, each
frequency band is displayed in a different color. Below the
graph are edit boxes, one for each crossover frequency point.
Edit each frequency by clicking the up or down arrows or
click directly in the edit box to display the cursor and type in
the new crossover frequency directly. The RPM 26i accepts
crossover frequency in 1 Hertz steps and all values must be
typed in Hertz.
Editing the crossover frequency values is also possible by
clicking directly on the curve. Click directly on the intersec-
tion of the two curves to successfully grab and edit the
crossover frequency. The curves change color when success-
fully grabbed. The horizontal position of the cursor dictates
what frequency value is assigned once the cursor is dropped.
Note: It is wise to alter crossover frequencies directly on
the graph only when the Outputs are muted or when the
RPM 26i is not connected to amplifiers and speakers. This
avoids the potential disasters of slipping with the mouse or
reaching for your coffee and accidentally clicking the mouse!
For these reasons, the area to successfully grab the crossover
curve is small.
For both the 2-way and 3-way crossover blocks, the
default crossover filter type is Linkwitz-Riley, 24 dB per
octave (4
th order) filters. The crossover frequency points are
also locked together making all adjustments equivalent to
familiar analog crossovers. For those with the proper analysis
tools to properly adjust other crossover filter types, the RPM
26i crossovers contain an Advanced Mode. In the crossover
detail window, clicking the right mouse button pops up a
menu that provides access to the Advanced Mode. A Warning
box is displayed before one can enter Advanced Mode. Check
the
Don’t ask me again box if you “know what you’re
doing” and this whole warning business is beneath you. Click
OK only if you have the proper equipment to ensure your
crossover adjustments are helping, not hindering your efforts.
Hit
Cancel if you lack the proper analysis tools.