NTi Audio XL2 Sound Level Meter - Manual (Page 116)

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STIPA
Speech Intelligibility STIPA (optional)
The STIPA analyzer option allows reliable measurement of
the speech transmission index within 15 seconds. Besides
the single value STI or CIS test result, a detailed view of the
modulation indices and individual band level results is provid-
ed. The STIPA analyzer meets the latest standard edition 4.0
IEC 60268-16, released in 2011. The XL2 Supports also noise
corrections, automated averaging of measurements and the
older standard editions 2.0 and 3.0.
The speech intelligibility depends on the following system pa-
rameters:
Signal-to-noise ratio •
Psychoacoustic masking effects •
Sound pressure level •
Ambient noise level •
Reverberation time RT60 •
Reflections •
Frequency response •
Distortion •
The speech intelligibility measurement STIPA is an option for
the XL2 Audio and Acoustic Analyzer. Ask the local representa-
tive for purchasing details.
STIPA Signal Source
Utilize the applicable STIPA signal source dedicated for your
installation configuration:
NTi Audio
TalkBox The NTi Audio TalkBox simulates a person talking
at a precise acoustic level, enabling the measure-
ment of the complete signal chain including the
microphone.
Place the NTi Audio TalkBox in front of the mi- •
crophone at the typical position of the talking
persons head.
Select Track 1 for the STIPA test signal.
•
Select Output Mode to Speaker; you should •
hear the STIPA test signal.
Minirator
MR-PRO The Minirator MR-PRO is used for electrical signal
injection into public address systems that com-
monly use alarm messages from a hard drive
(systems without a microphone).
CD Player The NTi Audio CD “STIPA V1.1”, included in the
package, can be used with a professional CD
player. For details see the chapter STIPA Mea-
surement Hints.
The standard STIPA signal is based on a band-limited random
noise of a male speech spectrum.