Two Techniques of Measuring System Equalization in the Objective Assessment of Speech Intelligibility

The advantage of speech control of unmanned aerial vehicles, which occurs indoors, is the ability to reduce speech distortions caused by noise action. However, the disadvantage of such control is the negative impact of reverberation on speech intelligibility. Therefore, it is advisable to perform a preliminary assessment of speech intelligibility in the room before the session of unmanned aerial vehicle controlling. This assessment can be performed by the modulation method, using the room impulse response estimate. If a non-professional quality loudspeaker and microphone are used to estimate the room impulse response, errors in the room impulse response estimate can significantly affect the results of speech intelligibility assessment. In this paper, two techniques of equalizing of non-professional quality level audio equipment used in assessing the room impulse response have been compared. It is shown that a dividing the frequency response of the “loudspeaker-room-microphone” system into the frequency response of the “loudspeaker-microphone” system provides almost the same equalization quality as a more complex technique of adaptive filtering, if the amplitude frequency response unevenness of the “loudspeaker-microphone” system does not exceed 12–13 dB in the frequency band 100–5000 Hz.