Ivie IE-45 RTA - Real Time Analysis - Manual (Page 10)

Ivie IE-45 Manual
page 10
Pref. Curve, LED Display, Weighting
Preferred Curve Overlay
The Preferred Curve overlay is an IE-45 feature that allows the user to create a target overlay which can be dis-
played on the screen. This can be a valuable aid to the equalization process. Users often use a target curve to
contour the frequency response of a system to a desired result.
Creating a Preferred Curve: The preferred, or target curve, is nothing more than a line created by the user
that is overlaid on the screen to help visualize a desired result. To create a Preferred Curve, tap the PE memory
stylus button to the far right of the row of memory stylus buttons. The background on the PE button will change
to white, and the RTA display will move to a special 1/3 octave display with all bars touching the center refer-
ence line. Use the "joystick" button to move the blue 1/3 octave bar right or left to a 1/3 octave you wish to
change, or tap the desired 1/3 octave bar with the stylus. Use the joystick up/down to change the level of the
1/3 octave. Move to the next 1/3 octave and change that level, and so on. You can create a roll-off target curve
or other special spectra targets in this way.
Tap the Preferred Curve stylus button again and the background will turn green, the button text will change to
PT (preferred target), and the preferred target curve overlay will appear on-screen. Tap the button again and the
background will change to buff while the target curve is removed from the display. Tap the button again and it
changes to white as the Preferred Curve entry screen again appears so further editing, if desired, can be done.
Tap the button one more time and it turns green while the Preferred Curve is displayed.
Saving a Preferred Curve: The Preferred Curve you have created can be saved to the analyzer memory very
easily. You can save several Preferred Curves and call them back from memory as needed. To save a
Preferred Curve, tap the main screen Memory button, which will bring up the Memory Management screen.
Note that the default name of the Preferred Curve is "Preferred.ivi." Tap the "Store" button immediately to the
right of the file name and you will see a dialog box that allows you to change the name of the file to something
more descriptive (you can also change the file storage location if you wish). When finished editing, tap "OK" to
store the curve.
Loading a Preferred Curve from Memory: To load a previously stored Preferred Curve from memory, simply
tap the main screen Memory stylus button to bring up the Memory Management screen. Memory slot # 9 is
used for storing and recalling Preferred Curves. Tap the button labeled "Load" for the Preferred Curve memory
location and you will see a dialog that allows you to select the desired preferred curve. Tap "OK" and the curve
will be loaded into the Preferred Curve memory location. The IE-45 comes with one pre-loaded Preferred
Curve, labeled "Preferred.ivi" that can be loaded into the display. It is a high end roll-off curve used as a target
for large venue sound system EQ.
LED Display: Many users are familiar with the LED display of Ivie's IE-30A analyzer. To have the IE-45 emu-
late the IE-30's LED display, tap the "Function" pull-down menu at the bottom of the main screen and choose
"RTA LEDs." The RTA display changes to "LEDs.”
Tip: The LED display can be useful in interpreting ampli-
tude information on the analyzer screen. By setting the dB scale to 5 dB/division each LED represents one dB
of amplitude. By setting 10 dB/division each LED represents 2 dB of amplitude, and by setting 15 dB/division,
each LED represents 3 dB of amplitude change.
SPL Weighting and the RTA Display: Some users prefer to see the normal weighting filters that are applied to
SPL measurements also applied to the visual spectrum of the on-screen RTA. The IE-45 allows you to choose
whether or not the RTA display will show an unweighted display or a weighted display. To apply weighting filters
to the RTA display, tap on the "Options" pull-down menu at the bottom of the screen and select "RTA Weighting."
Whatever weighting filter is selected for the SPL meter when in RTA mode (the SPL meter is in the small win-
dows in the lower right of the screen) will then be applied to the RTA display. Unchecking (by again tapping) this
selection will remove weighting from the RTA display.