Concentration of reflected sound in a room treated with cube corner retroreflectorsa).

A room was treated to be predominantly retroreflective in the high frequency range by introducing arrays of cube corner retroreflectors (CCRs) over most surfaces (excluding the floor). In a small room (volume 55 m3), 156 CCRs in the form of square trihedra with 350 mm edge lengths were used as wall and ceiling treatment. The horizontal plane distribution of reflected energy was measured from omnidirectional sources, and a head and torso simulator was used to measure voice support.

Separate effects of auditory and visual room size on auditorium seat preference: a virtual reality study.

Audiovisual integrations and interactions happen everywhere, including in music concerts, where combined visual and auditory perception contributes to overall enjoyment. Thirty-three participants evaluated their overall subjective preference at various seats in four virtual auditoria, which comprised congruent and incongruent auditory and visual renders of two auditoria that differ only in size. Results show no significant difference between participants who completed the experiment in a fully calibrated and standardized laboratory environment and participants who completed remotely using various VR equipment in various environments.

Effect of voice support level and spectrum on conversational speech.

One's own voice (autophony) is transmitted to the ears as direct airborne sound, bone conduction, and indirect airborne sound from reflections characterized by overall gain and spectro-temporal features. This study investigates how the spectral profile and gain of simulated indirect airborne sound, quantified as voice support (ST), affect the speaking voice of talkers. Pairs of participants performed a conversation elicitation task in anechoic conditions.

Chamber musicians' acoustic impressions of auditorium stages: Relation to spatial distribution of early reflections and other parameters.

Characterizing stage acoustics using objective parameters has seen some recent resurgence-several studies have noted the importance of the directionality of early stage reflections to musicians, which is not adequately represented using existing omnidirectional stage-support parameters. This study examines the subjective impressions of 19 chamber musicians against omnidirectional [reverberation time, early and late support (ST, ST), etc.], and proposed spatially-defined parameters (TH and TS), along with simple ratios of stage dimensions derived from measurements on eight purpose-built stages.

Comparison of psychoacoustic-based reverberance parameters.

This study compared psychoacoustic reverberance parameters to each other, as well as to reverberation time (RT) and early decay time (EDT) under various acoustic conditions. The psychoacoustic parameters were loudness-based RT (T), loudness-based EDT [EDT; Lee, Cabrera, and Martens, J. Acoust.

Effect of a chamber orchestra on direct sound and early reflections for performers on stage: A boundary element method study.

Early reflections are known to be important to musicians performing on stage, but acoustic measurements are usually made on empty stages. This work investigates how a chamber orchestra setup on stage affects early reflections from the stage enclosure. A boundary element method (BEM) model of a chamber orchestra is validated against full scale measurements with seated and standing subjects in an anechoic chamber and against auditorium measurements, demonstrating that the BEM simulation gives realistic results.

Autophonic Loudness of Singers in Simulated Room Acoustic Environments.

Objectives: This paper aims to study the effect of room acoustics and phonemes on the perception of loudness of one's own voice (autophonic loudness) for a group of trained singers.

Methods: For a set of five phonemes, 20 singers vocalized over several autophonic loudness ratios, while maintaining pitch constancy over extreme voice levels, within five simulated rooms.

Results: There were statistically significant differences in the slope of the autophonic loudness function (logarithm of autophonic loudness as a function of voice sound pressure level) for the five phonemes, with slopes ranging from 1.

Assessing Linearity in the Loudness Envelope of the Messa di Voce Singing Exercise Through Acoustic Signal Analysis.

Messa di voce (MDV) is a singing exercise that involves sustaining a single pitch with a linear change in loudness from silence to maximum intensity (the crescendo part) and back to silence again (the decrescendo part), with time symmetry between the two parts. Previous studies have used the sound pressure level (SPL, in decibels) of a singer's voice to measure loudness, so as to assess the linearity of each part-an approach that has limitations due to loudness and SPL not being linearly related. This article studies the loudness envelope shapes of MDVs, comparing the SPL approach with approaches that are more closely related to human loudness perception.

Change in messa di voce characteristics during 3 years of classical singing training at the tertiary level.

A 3-year longitudinal study was conducted to investigate changes in vocal quality as a result of singing training at a tertiary level conservatorium in Australia. Singers performed a messa di voce (MDV) at intervals of 6 months over the 3-year period of training. The study investigated the evolving acoustic features of the singers' voices exhibited during the MDV, including sound pressure level (SPL), short-term energy ratio (STER), duration, and vibrato parameters of the fundamental frequency (F0), SPL, and STER.

Towards a method for loudness-based analysis of the sound of one's own voice.

This paper outlines the steps in objectively estimating the time-varying loudness of one's own voice in a room (i.e. autophonic loudness).

The effect of loudness on the reverberance of music: reverberance prediction using loudness models.

This study examines the auditory attribute that describes the perceived amount of reverberation, known as "reverberance." Listening experiments were performed using two signals commonly heard in auditoria: excerpts of orchestral music and western classical singing. Listeners adjusted the decay rate of room impulse responses prior to convolution with these signals, so as to match the reverberance of each stimulus to that of a reference stimulus.

Non-auditory factors affecting urban soundscape evaluation.

The aim of this study is to characterize urban spaces, which combine landscape, acoustics, and lighting, and to investigate people's perceptions of urban soundscapes through quantitative and qualitative analyses. A general questionnaire survey and soundwalk were performed to investigate soundscape perception in urban spaces. Non-auditory factors (visual image, day lighting, and olfactory perceptions), as well as acoustic comfort, were selected as the main contexts that affect soundscape perception, and context preferences and overall impressions were evaluated using an 11-point numerical scale.

Long-term horizontal vocal directivity of opera singers: effects of singing projection and acoustic environment.

Vocal directivity refers to how directional the sound is that comes from a singer's mouth, that is, whether the sound is focused into a narrow stream of sound projecting in front of the singers or whether it is spread out all around the singer. This study investigates the long-term vocal directivity and acoustic power of professional opera singers and how these vary among subjects, among singing projections, and among vastly different acoustic environments. The vocal sound of eight professional opera singers (six females and two males) was measured in anechoic and reverberant rooms and in a recital hall.

Effects of training on time-varying spectral energy and sound pressure level in nine male classical singers.

The male classical singing voice is a musical instrument that is very important in western culture. It has many acoustic features which should change and improve over the period in which the singer trains. In this study we compare nine singers in different stages of training, from university level students through to international soloists.

The effect of visual and auditory cues on seat preference in an opera theater.

Opera performance conveys both visual and auditory information to an audience, and so opera theaters should be evaluated in both domains. This study investigates the effect of static visual and auditory cues on seat preference in an opera theater. Acoustical parameters were measured and visibility was analyzed for nine seats.

Influence of fundamental frequency and source elevation on the vertical localization of complex tones and complex tone pairs.

This study investigates the vertical localization of single complex tones (monads) and simultaneous complex tone pairs (dyads), especially as it is affected by their fundamental frequency and source elevation. Two complex tone timbres are considered: one consisting of five low-order harmonics, and the other of all odd harmonics (a square wave). Sound sources were at -15, 0, 15, and 30 deg from the horizontal plane at ear height.

The acoustic characteristics of professional opera singers performing in chorus versus solo mode.

In this study, members of a professional opera chorus were recorded using close microphones, while singing in both choral and solo modes. The analysis included computation of long-term average spectra (LTAS) for the two song sections performed and calculation of singing power ratio (SPR) and energy ratio (ER), which provide an indication of the relative energy in the singer's formant region. Vibrato rate and extent were determined from two matched vowels, and SPR and ER were calculated for these vowels.

Self-to-other ratios measured in an opera chorus in performance.

Four volunteer members of the chorus of Opera Australia, representing four different voice categories, wore binaural pairs of wireless microphones during a penultimate dress rehearsal on the Opera Theater stage of the Sydney Opera House. From the recordings, data were obtained on sound levels and on the self-to-other ratios (SORs). The sound levels were comparable to those found in loud music in chamber choir performance.