Equal autophonic level curves under different room acoustics conditions

Abstract

The indirect auditory feedback from one's own voice arises from sound reflections at the room boundaries or from sound reinforcement systems. The relative variations of indirect auditory feedback are quantified through room acoustic parameters such as the room gain and the voice support, rather than the reverberation time. Fourteen subjects matched the loudness level of their own voice (the autophonic level) to that of a constant and external reference sound, under different synthesized room acoustics conditions. The matching voice levels are used to build a set of equal autophonic level curves. These curves give an indication of the amount of variation in voice level induced by the acoustic environment as a consequence of the sidetone compensation or Lombard effect. In the range of typical rooms for speech, the variations in overall voice level that result in a constant autophonic level are on the order of 2 dB, and more than 3 dB in the 4 kHz octave band. By comparison of these curves with previous studies, it is shown that talkers use acoustic cues other than loudness to adjust their voices when speaking in different rooms.

Measurement and prediction of voice support and room gain in school classrooms

“…(13) in Ref. 23 for the range ST V > À14.5 dB. As an example, one can evaluate the effect of reducing the reverberation time in a room of 200 m 3 from 1 to 0.5 s in terms of voice power level demands.…”

“…The ST V is influenced by the early reflections which cannot be accurately represented with a statistical model such as the one in Eq. (23), which only aims at predicting a position-averaged value.…”

“…The voice support is strongly negatively correlated to the logarithm of the volume, as expected from the prediction model in Eq. (23) and Fig. 3.…”

“…The room gain is defined as the gain applied by the room boundaries to the voice of the speaker at his/her own ears (considering the airborne direct component as the "normal" voice level) and has been used in several studies. 18,[22][23][24][25] The voice support is defined as the level difference between the reflections of one's own voice reaching the ears and the voice propagating directly from the mouth to the ears. It is an alternative way of expressing the room gain, which has a larger dynamic range.…”

Speakers’ comfort and voice level variation in classrooms: Laboratory research

“…The much higher value of room effect found by Brunskog et al 5,6 (À13.5 dB/dB G ) included the effect of rising the voice level to address listeners at longer distances in the largest rooms (which had the lowest room gain values), corresponding therefore to an ecological location of the listeners. Pelegrin-Garcia et al 11 determined the variations in voice level that would cause the loudness level of a talker's own voice (i.e., the autophonic level) to be constant under different room acoustic conditions, characterized by the room gain or the voice support. The magnitude of the room effect for a talker addressing a listener at 1.5 m (À1.6 dB/dB G ) is comparable to the variations in voice level that keep the autophonic level constant (À1.5 dB/dB G for a range of room gain between 0 and 0.8 dB), indicating that, in situations of low vocal demands, talkers just adjust their voice level to hear themselves equally loud Determining the magnitude of the room effect in more representative acoustic conditions would give a better understanding of the interaction between a talker and the physical environment, and would be a useful guideline to assess the consequences of different acoustics designs in rooms for speech.…”