User manual

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STIPA
Speech Intelligibility STIPA (optional)
The STIPA analyzer option allows reliable measurement
of the speech transmission index (STI) within 15 sec-
onds. Besides the single value STI or CIS (= common intel-
ligibility scale) test result, a detailed view of the modula-
tion indices and individual band level results is provided.
The STIPA analyzer meets the latest standard edition 4.0
IEC 60268-16, released in 2011. The XL2 also supports noise
corrections, automated averaging of measurements and the
older standard editions 2.0 and 3.0.
The intelligibility of speech depends on:
Signal-to-noise ratio•
Psychoacoustic masking effects•
Sound pressure level•
Ambient noise level•
Reverberation time RT60•
Reflections•
Frequency response•
Distortion•
The speech intelligibility measurement function STIPA is an op-
tion for the XL2 Audio and Acoustic Analyzer. Ask your local
representative for purchasing details.
Signal Source
Choose the applicable STIPA test signal source:
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 STI Measure-
ment Hints.
The standard STIPA signal is based on random noise limited to
the bands contained in a male speech spectrum.