Second European Conference on Speech Communication and Technology

Genova, Italy
September 24-26, 1991


On the Mutual Dependency of Octave-Band-Specific Contributions to Speech Intelligibility

Herman J. M. Steeneken, Tammo Houtgast

TNO Institute for Perception, Soesterberg, The Netherlands

Currently objective me*asures for predicting the intelligibility of speech are modelled as a linear summation of the contribution of individual frequency bands. The Articulation Index (AI, French and Steinberg, 1947) and Speech Transmission Index (STI, Steeneken and Houtgast, 1980) are based on such a model. There is evidence that this concept is not correct for conditions with gaps or selective masking present in the frequency domain. We designed an experiment where the contribution of individual frequency bands is studied. For this purpose the speech signal is subdivided into seven octave bands ranging from 125 Hz to 8 kHz. For 26 different combinations of minimal three octave bands the CVC-word score (Consonant-Vowel-Consonant, nonsense words) was obtained at three signal-to-noise ratios. A revised model, which accounts for mutual dependency between adjacent octave bands by the introduction of a so-called redundancy factor will be proposed. Consequences for the existing objective measures are discussed.

Full Paper

Bibliographic reference.  Steeneken, Herman J. M. / Houtgast, Tammo (1991): "On the mutual dependency of octave-band-specific contributions to speech intelligibility", In EUROSPEECH-1991, 1133-1136.