Measurement of speech intelligibilty according to DIN/IEC 60268-16
- Supports STI STIPA RASTI.
- Measurement can be done via impulse response or modulated noise.
Speech-intelligibility is the key feature to human communication. For evacuation systems, telecommunication, announcement systems (e.g. train stations) or rooms for education, poor speech-intelligibility will degrade their function or even become a security issue.
In many countries there exist limits for the speech-intelligibility. For new public buildings a certification measurement is required and the speech-intelligibility results must be documented. In most cases this must be performed according to IEC 60849 or ISO 7240-16.
The first orginal measurements were based on statistical analysis of listening tests. In contrast, the STI-method specified in DIN/IEC 60268-16 is an objective method. It uses special test signals (modulated noise) that simulate human voice and computes the influence of a transmission channel which degrades the speech-intelligibility.
The speech intelligibility of a transmission channel depends on:
- the speech level
- frequency response of the channel
- non-linear distortions
- background noise level
- quality of the sound reproduction equipment
- echos (reflections with delay > 100ms)
- the reverberation time
- psychoacoustic effects (masking effects)
The STI method uses 7 octave bands in the range of 125Hz to 8000Hz. It computes a single value, that reflects the speech-intelligibility.
This value can be in the range of 0 to 1.0. A value of 0 is equivalent to a very poor speech-intelligibility. 1.0 is an ideal channel with excellent speech transmission.
Features
- Conforms to IEC 60268-16:2003 and 2011
- STI, STIPA, RASTI
- Very easy usage. Make your first STIPA measurement within 2 min.
- Measurement via modulated noise and room impulse response. (direct and indirect method)
- Background noise can be included via spectral values or .wav file. No spreadsheet calculation required.
- Auditory masking conforms to IEC 60268-16 ED 3.0 (2003) and ED 4.0 (2011)
- Displays modulation indices for each band
- Octave analyzer
- Speech level measurement according to IEC 60268-16:2011 Annex J.2
- Easy export of data
You can find the quick guide here
