Abstract: In a device for adjusting a movable electro-acoustic sound transducer, an optical duct is connected to the sound transducer which only allows an object, such as a display table or a data display unit, to be viewed completely in one specific position. This position is unambiguously reproducible and so is the position of the sound transducer or microphone relative to the mouth of the speaker. The optical duct may comprise diaphragms or a tube, possibly with intermediate walls, or a phase amplitude grating.The object may be a display unit and the device further comprises a device for generating variable data on the display. If used for speaker identification, the variable data generator projects consecutive instructions on the display so that, the speech recognition process is controlled automatically. The speaker to be identified is then required to keep his mouth in the correct position relative to the microphone.

Abstract: An improved method of verifying the speaker from whom long term spectral characteristics have been derived during a learning phase. Mean values and distance thresholds have been calculated and stored. Improved recognition is obtained by incorporating into the stored values additional values of speech samples in ranges situated outside the distance threshold value. When, during verification, a speech sample not situated within the distance threshold value is encountered its distance from the additionally stored speech samples is successively determined and compared with the separate distance threshold value. The speaker is rejected only if the speech sample to be verified is not situated at a sufficiently small distance from any of the additionally stored speech samples. The method thus increases the recognition range to better approximate the actual distribution of speech samples of the learning phase.