Audioscan Axiom - Manual (Page 84)

Axiom ® User's Guide Version 1.8  May 2015
SII calculation in Speechmap
The Axiom calculates a Speech Intelligibility Index (SII) value (in %) for unaided speech and for each aided
test. The calculations use the 1/3 octave band method of ANSI S3.5 –1997 without the 160 Hz band and without
masking effects with results expressed as a % by multiplying by 100. Level distortion effects are included but no
hearing loss desensitization is applied. An idealized speech region of LTASS +/- 15 dB is used.
The speech recognition associated with a given SII is a function of the test material and the cognitive abilities of
the listener. There is considerable individual variability in relating the SII to speech recognition, especially
amongst impaired listeners. The following shows expected nominal recognition scores vs SII for normals when
using a variety of speech stimulus conditions. (Killion and Mueller, Hearing Journal, January, 2010 pp 10-15)
Using Custom Stimuli in Speechmap
Custom digital sound files can be used as stimuli in Speechmap. If you connect a USB stick with WAV files on
it to the Axiom, Speechmap will make those files available as stimulus selections. This feature provides the
freedom of using any stimulus in Speechmap with all the features that Speechmap offers. Please note that fitting
targets are not available for custom stimuli.
A USB stick is required for this feature. It is highly recommended that the USB stick is formatted for data using
the Audioscan Updater prior to using this feature. The Audioscan Updater comes with any current Audioscan
software download or Cd. Visit
www.audioscan.com to obtain software updates.
To use digital sound files as stimuli in Speechmap:
1. Connect a USB stick to your PC.
2. Format the USB stick for data using the Audioscan Updater.
3. Create digital sound files that are compatible with Speechmap (see Creating WAV files for Speechmap).
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