The timbre of the voice as perceived by the singer him-/herself

Abstract

Fifteen professional singers sang simple vocal exercises at different pitches. The sung excerpts were recorded, and seven modified versions were created from each recording. The modifications were then played to the participant and (s)he had to assess the similarity of these stimuli to the perception of his/her own voice during the act of singing. Participants rated as most similar those stimuli which were modified by the filter whose frequency response most closely resembled a trapezoid, which was created by taking into account 1) the diffracting air conduction component from the mouth of the singer to his ear channel, 2) the bone conduction component, and also 3) the influence of the stapedius reflex on the sensitivity of his/her auditory system.

Key words::

• Bone conduction
• middle ear reflex
• singing
• stapedius reflex
• timbre

Acknowledgements

This paper was presented in part at the 9th Pan-European Voice Congress (PEVOC), Marseille, France, 31 August–3 September 2011 and in joint 12th International Conference on Music Perception and Cognition (ICMPC); 8th Triennial Conference of the European Society for the Cognitive Sciences of Music (ESCOM), Thessaloniki, Greece, 23–28 July 2012.

The author wishes to thank all persons who participated in the experiment and Professor Jaan Ross for insights and discussions.

Declaration of interest: The author reports no conflicts of interests. The author alone is responsible for the content and writing of the paper. This work has been supported by Estonian Research Council institutional research grant #12-1.

Appendix

The influence of room reflections

This section gives a more detailed explanation of why we consider the impact of room reflection components insignificant for the perception of our own voice in typical situations on concert stages.

The theoretical foundations of room acoustics are addressed, for example, in Meyer (13 p. 191). When the sound source radiates continuous sound, a diffuse sound field emerges, the level of which is almost uniform throughout the whole room. The SPL of this diffuse sound field may be calculated as

where L_w represents the sound power level of the source and D_a the room damping index. D_a is given by

where V represents the volume of the room in m³ and T its reverberation time in seconds, and where –14 dB is the result of several constants.

The numerical value in decibels of the sound source power (which does not depend on distance) equals the numerical value of the SPL in decibels when measured at a distance of 28 cm from the sound source, assuming the radiation of the source to be omnidirectional. In the case of a directional sound source, the value of the distance at which these numerical values become equal depends on the angle at which the measurement is made. In singing voice research it is customary to position the measurement microphone at a point 30 cm in front of the mouth (14).

The single first reflections which return to the vocalist may have a higher SPL than the SPL of a diffuse field. In calculating the strength of these reflections we need to bear in mind two factors: first that the SPL is inversely related to the distance, according to the formula

where L₂ and L₁ are the SPLs at the distance of r₂ and r₁ from the sound source (doubling the distance diminishes SPL by 6 dB); and secondly, that part of the sound energy is absorbed by the reflecting surface. As in typical performance situations the path of the sound from the vocalist's mouth to his/her hearing system through room reflections is much longer than either the bone conduction path or the diffracting air component path, the impact of room reflections on the perception of one's own voice is usually insignificant.