NTi Audio XL2 Sound Level Meter - Manual (Page 119)

119
STIPA
7 Measurement Unit
The STIPA result is displayed in STI (Speech Transmission
Index) or CIS (Common Intelligibility Scale), whereby CIS is
calculated as CIS = 1 + log STI.
8 Edition of Standard IEC60268-16
ed4.0 actual edition released in 2011 with continuous
level dependent auditory masking function
ed3.0 old edition released in 2003 with stepped level
dependent auditory masking function
ed2.0 old edition released in 1998 with fixed masking
function
0.5
0.6
0.7
0.8
0.9
1
20 40 60 80 100 120
ST
I (
be
st
c
as
e)
Level L
Aeq
Comparison of the IEC 60268-16 Editions
edition 2.0, 1998
edition 3.0, 2003
edition 4.0, 2011
9 Progress Bar
Measurement status indication; the single STIPA measure-
ments takes 15 seconds. The actual measurement time
and measurement status are indicated here.
10 Page Selector
Select between these pages:
Speech intelligibility measurement result
Table result page with modulation indexes and
sound levels for each octave band
On-site averaging of results.
Ambient Noise Correction
The page button toggles between the 123 - Tab - Avr
screens. These pages show the speech intelligibility mea-
surement results. The page Cor offers setting the noise
spectra prior the STI measurement.
11 Octave Bands
Frequencies 125 Hz - 8 kHz in 1/1 octave band resolution.
12 Sound Pressure Level Leq
Individual time-averaged octave band level Leq.