NTi Audio Acoustilyzer AL1 - Manual (Page 56)

56 57
• Start the STI-PA test signal.
• Set the acoustical sound pressure level
of the PA system according the typical
emergency condition requirements, e.g.
85 dBAS.
• Press START on the AL1 menu to initiate
the measurement. Ensure that there is
no speaking or additional noise near the
measurement microphone during the
measurement.
A STI-PA measurement takes 15 seconds.
The elapsed test time is visible in the upper
measurement progress bar.
The test result tendency is shown on the
STI-PA bargraph below, marked with BAD,
PR (poor), FR (fair), GD (good) and EXLT
(excellent).
After the 15 seconds test cycle time the
Measurement Status Indication switches to
FINISHED and the final STI-PA test result
is displayed.
On the bargraph below the quality of the
speech intelligibility test result is displayed
as
• BAD 0.00 - 0.30 STI
• PR (poor) 0.30 - 0.45 STI
• FR (fair) 0.45 - 0.60 STI
• GD (good) 0.60 - 0.75 STI
• EXLT (excellent) 0.75 - 1.00 STI