Ivie IE-45 STI-PA - Speech Intelligibility Analysis - Manual (Page 2)

in the room so that the SPL meter indicates the Target SPL for this room.(or is at least within the
target level brackets)
Step 9 - OCTAVE LEVELS: An exclusive feature of Ivie's STI-PA system allow you to also
observe a "corrected Octave band" RTA display to determine the amplitude in each octave band
of the measurement. (Note: To use the RTA in Ivie's STI-PA application, you should play
STI-PA noise through the system. The RTA display is corrected to display AS IF the signal
were pink noise.) Tap on the "Octave" tab under the main display and a special screen will
display real-time octave band amplitudes for each of the seven octaves of the STI-PA
measurement. This can be useful in determining if there is enough energy in each octave of the
measurement. Further, if the user taps the "Mark Octave Levels" button in the RTA screen, the
seven amplitude values of the octave bands will be frozen at their present levels and indicated on
the screen by a blue line. Then, when the Save button in the main STI-PA screen is tapped, the
individual octave amplitudes indicated by the blue line are saved to the report. When the report
is saved-to-file, the octave information is saved along with the other STI-PA information as a .txt
file for export.. One set of SPL values can be saved for each measurement location, whether
single measurement or averaged.
A button is found to the left of the “Mark Octave Levels” button which will toggle the amplitude
range of the display from full range (110 dB SPL - 30 dB SPL) to a more practical range for
making STI-PS measurements (100 dB SPL - 60 dB SPL).
Step 10 - MICROPHONE LOCATION - Typically the IE-35 is hand-held with the microphone
attached. The microphone is held at a height above the floor that is representative of listeners
ear. The height would be lower in seating areas and higher in non-seating areas. A number of
measurements should be taken over the entire coverage area. The IE-35M microphone can also
be remoted from the IE-35 by means of an extension cable, and mounted to a microphone stand
if desired.
Step 11 - Press the "Start" button. The test will run for about 15 seconds. A countdown timer
will be displayed. The test results will be automatically displayed at the conclusion of the test.
During the test, if any talking or impulse noises should occur, the test should be discarded and
re-taken. Press the "Clear" button to discard the test. Detailed test data may be viewed by
pressing the "Report" button. Return to the main screen by pressing the "STI-PA" button.
Step 12 - Multiple tests (3-5) should be taken at each location and averaged together. Press the
"Avg." button to start or add another test to the average for that location. After you have
Averaged multiple tests you can save the results to the Job file by pressing the "Save" button.
You can view the Job file by pressing the "File" menu and "View Job File.."
Step 13 - Move to a new location and take additional tests and average them together. Then press
"Save". Repeat Step 11 until the job is completed.
Special Note - In the area just above the main STI-PA display an OverRange or UnderRange
indicator will appear if the input level of the source goes above or below the range where an
input will be accurate. As the on-screen STI-PA display, and the Report Screen also give
indications if there are problems with the STI-PA measurement, the Over/Under Range indicator
is just another indication to guide the user toward making useful measurements.