NTi Audio XL2 Sound Level Meter - Manual (Page 126)

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STIPA
STIPA with Ambient Noise Correction
Measuring the speech intelligibility index under realistic en-
vironmental conditions is often not feasible; e.g., playing the
test signal in a railway station at emergency levels during peak
hours will irritate passengers. Additionally, at rush-hour the
characteristics of ambient noise might be highly impulsive,
while a pre-requisite for accurate STIPA measurements is a
negligible impulsivity in the ambient noise. Under such circum-
stances the STIPA measurement should be shifted to a more
suitable time of the day; e.g. night time.
Measurement Sequence
First measure the ambient noise •
Secondly measure the speech intelligibility STIPA •
This sequence simplifies the STIPA measure-
ment as follows: The XL2 immediately displays
the STIPA result with ambient noise correction.
This result provides a guideline if repeated mea-
surements at the same location with averaging
is required. For details see the chapter STIPA
Measurement Hints.
Enable Ambient Noise Correction
Select the correction page • Cor.
Turn the rotary wheel • to select the parameter Ambient
Noise Correction and press enter .

The correction enables and the XL2 displays this screen: