Lombard Effect Research Articles

Sound absorbing chandeliers for multitalker noise control in large halls

During social gatherings in large halls, multiple conversations taking place simultaneously can lead to very high noise levels. Increasing the amount of sound absorption in the hall can be very effective in this context: due to the Lombard effect, the noise level drops with 6 dB when doubling the equivalent absorption area, while only a 3 dB drop occurs for sources of constant sound power. However, the possibilities for the absorptive treatment of existing venues can be highly limited, especially when dealing with architectural heritage. Therefore, in the present study, sound absorbing chandeliers, consisting of dense arrangements of absorbing objects, have been designed, developed, tested, and applied in a hard-walled historic hall that hosts social gatherings of more than 800 people. Experiments in the hall during busy events have confirmed the effectiveness of the chandeliers, yet it was also found that, since the ceiling has become the main absorptive surface, they loose efficiency due to the resulting sound field directionality. Furthermore, the individual vocal effort was observed to stay constant when the background nose level was decreasing. Both effects have been thoroughly studied and analyzed, and a prediction methodology to account for these effects has been proposed.

Analysis of the Spanish Auditory Test of Speech in Noise (PAHRE) in a Population with Hearing Loss.

Speech recognition in noise is one of the difficulties faced by people with hearing loss that increases with age. The recently developed Spanish Auditory Test of Speech in Noise (Prueba Auditiva de Habla en Ruido en Español, PAHRE) allows for the identification of these intelligibility difficulties in noise. The aim of this study was to assess speech recognition in noise in people with hearing loss and to test the benefits of the Lombard effect. The participants were 104 people with hearing difficulties, ranging in age from 37 to 98 years. The variables age, degree of hearing loss, presence of high-frequency dropout, and years of formal education were assessed. Psychometric curves were obtained as a function of signal-to-noise ratio as well as threshold values of speech reception as a function of age group for mild and moderate hearing loss. The results indicated that the speech reception threshold increased with both age and the degree of hearing loss, becoming particularly significant after the age of 70. Furthermore, it was found that the combined factors of age, degree of hearing loss, and educational level predicted a high percentage of the variability in the speech reception threshold. Therefore, the Spanish Auditory Test of Speech in Noise could be a useful clinical tool for diagnosis, monitoring, auditory rehabilitation planning, and hearing aid fitting.

Lombard speech detection in case of spatial separation between noise source and talkers of different genders

The spatial selectivity of hearing to speech signals was studied when the target signal and interference were separated by distance between their sources and the listener. In the work, the hypothesis about the improvement of hearing selectivity due to more intensive activation of the high-frequency binaural mechanism due to the shift of the speaker’s voice spectrum occurs in noisy environment towards high frequencies, was tested. The thresholds for detecting the target signal – a two-syllable word uttered by male or female, were evaluated in the two-alternative two-interval forced choice paradigm in 4 series. Series differed by the type of target signal (ordinary or Lombard speech) and the location of target source and noise (multi-talker noise) one. The both sources were located at a distance of 1 and 4 m opposite the subject at the level of his head. The detection threshold was defined as the ratio of signal and noise levels at the listener’s place (S/N). The threshold for detecting the target signal (male and female speaker voices together) was -11 dB S/N for ordinary as well as Lombard speech. It did not depend on which of the sources - the target signal or noise, was closer to the listener. In normal speech, the detection thresholds on average differed for male and female voices, but the difference was not significant. In Lombard speech, these thresholds were significantly different: for a male voice, the threshold at a detection level of 0.67 was -10 dB S/N, and for a female voice – -12.5 dB S/N.

BELMASK—An Audiovisual Dataset of Adversely Produced Speech for Auditory Cognition Research

In this article, we introduce the Berlin Dataset of Lombard and Masked Speech (BELMASK), a phonetically controlled audiovisual dataset of speech produced in adverse speaking conditions, and describe the development of the related speech task. The dataset contains in total 128 min of audio and video recordings of 10 German native speakers (4 female, 6 male) with a mean age of 30.2 years (SD: 6.3 years), uttering matrix sentences in cued, uninstructed speech in four conditions: (i) with a Filtering Facepiece P2 (FFP2) mask in silence, (ii) without an FFP2 mask in silence, (iii) with an FFP2 mask while exposed to noise, iv) without an FFP2 mask while exposed to noise. Noise consisted of mixed-gender six-talker babble played over headphones to the speakers, triggering the Lombard effect. All conditions are readily available in face-and-voice and voice-only formats. The speech material is annotated, employing a multi-layer architecture, and was originally conceptualized to be used for the administration of a working memory task. The dataset is stored in a restricted-access Zenodo repository and is available for academic research in the area of speech communication, acoustics, psychology and related disciplines upon request, after signing an End User License Agreement (EULA).

롬바르드 효과가 아동과 성인의 말소리 산출에 미치는 영향: 음향학적 특성과 모음공간면적을 중심으로

롬바르드 효과가 아동과 성인의 말소리 산출에 미치는 영향: 음향학적 특성과 모음공간면적을 중심으로

"Lombard Effect" and Voice Changes in Adductor Laryngeal Dystonia: A Pilot Study.

The aim was to describe the acoustic, auditory-perceptive, and subjective voice changes under the Lombard effect (LE) in adductor laryngeal dystonia (AdLD) patients. Subjective perception of vocal effort (OMNI Vocal Effort Scale OMNI-VES), Maximum Phonation Time (MPT), and the perceptual severity of dysphonia (GRBAS scale) were assessed in condition of stillness and under LE in 10 AdLD patients and in 10 patients with typical voice. Speakers were asked to produce the sustained vowel /a/ and to read a phonetically balanced text aloud. Using the PRAAT software, the following acoustic parameters were analyzed: Mean Pitch (Hz), Minimum and Maximum Intensity (dB), the Fraction of Locally Unvoiced Frames, the Number of Voice Breaks, the Degree of Voice Breaks (%), the Cepstral Peak Prominence-Smoothed (CPPS) (dB). Under LE, the AdLD group showed a decrease of both G and S parameters of GRBAS and subjective effort, mean MPT increased significantly; in the controls there were no significant changes. In both groups under LE, pitch and intensity of the sustained vowel /a/ significantly increased consistently with LE. In the AdLD group the mean gain of OMNI-VES score and the mean gain of each parameter of the speech analysis were significantly greater than the controls' ones. Auditory feedback deprivation obtained under LE improves subjective, perceptual-auditory, and acoustics parameters of AdLD patients. These findings encourage further research to provide new knowledge into the role of the auditory system in the pathogenesis of AdLD and to develop new therapeutic strategies. 4 Laryngoscope, 134:3754-3760, 2024.

The Lombard effect in children with cochlear implants: suprasegmental aspects

ABSTRACT Children with cochlear implants (CI) communicate in noisy environments, such as in classrooms, where multiple talkers and reverberation are present. Speakers compensate for noise via the ‘Lombard effect’. The present study examined the Lombard effect on the intensity and duration of stressed vowels in the speech of children with Cochlear Implants (CIs) as compared to children with Normal Hearing (NH), focusing on the effects of speech-shaped noise (SSN) and speech-shaped noise with reverberation (SSN+Reverberation). The sample consisted of 7 children with CIs and 7 children with NH, aged 7–12 years. Regarding intensity, a) children with CIs produced stressed vowels with an overall greater intensity across acoustic conditions as compared to NH peers, b) both groups increased their stressed vowel intensity for all vowels from Quiet to both noise conditions, and c) children with NH further increased their intensity when reverberation was added to SSN, esp. for the vowel /u/. Regarding duration, longer stressed vowels were produced by children with CIs as compared to NH in Quiet and SSN conditions but the effect was retained only for the vowels /i/, /o/ and /u/ when reverberation was added to noise. The SSN+Reverberation condition induced systematic lengthening in stressed vowels for children with NH. Furthermore, although greater intensity and duration ratios of stressed/unstressed syllables were observed for children with NH as compared to CIs in Quiet condition, they diminished with noise. The differences observed across groups have implications for speaking in classroom noise.

Immersive auditory awareness: A smart earphones platform for education on noise-induced hearing risks

The Audio Research Platform developed by the ÉTS-EERS Industrial Research Chair in In-Ear technologies is a digital audio processing wearable device that features a powerful Digital Signal Processor and a pair of wired earplugs featuring outer- and inner-ear microphones as well as miniaturize loudspeaker. ARP has been used since over the last 2 decades by CRITIAS to develop new algorithms for advanced hearing protection and communication in noise, as well as in-ear audio sensing. In this adaptation, the ARP enables transparent hearing of ambient sounds, simulates varying degrees of hearing loss, and includes a tinnitus simulator. ARP also functions as a personal music player, monitoring playback levels and displaying the “Age of your ears”) a metric recently proposed by CRITIAS), predicting accelerated auditory aging from excessive music playback. In the playback mode, wearers experience pre-recorded noise, prompting vocal adjustments known as the “Lombard Effect.” ARP analyzes the wearer's voice using the outer-ear microphone, illustrating level and pitch shifts in speech due to a noisy environment. This paper details ARP's technical aspects, positioning it as a powerful tool to inform the public about noise-induced hearing loss and promote awareness and prevention through enjoyable real-time demonstrations.

Optimization-based modeling of Lombard speech articulation: Supraglottal characteristics.

This paper shows that a highly simplified model of speech production based on the optimization of articulatory effort versus intelligibility can account for some observed articulatory consequences of signal-to-noise ratio. Simulations of static vowels in the presence of various background noise levels show that the model predicts articulatory and acoustic modifications of the type observed in Lombard speech. These features were obtained only when the constraint applied to articulatory effort decreases as the level of background noise increases. These results support the hypothesis that Lombard speech is listener oriented and speakers adapt their articulation in noisy environments.

Modificações do feedback auditivo e seus efeitos sobre a voz de indivíduos adultos: uma revisão de escopo

ABSTRACT Introduction The auditory perception of voice and its production involve auditory feedback, kinesthetic cues and the feedforward system that produce different effects for the voice. The Lombard, Sidetone and Pitch-Shift-Reflex effects are the most studied. The mapping of scientific experiments on changes in auditory feedback for voice motor control makes it possible to examine the existing literature on the phenomenon and may contribute to voice training or therapies. Purpose To map experiments and research results with manipulation of auditory feedback for voice motor control in adults. Method Scope review following the Checklist Preferred Reporting Items for Systematic reviews and Meta-Analyses extension (PRISMA-ScR) to answer the question: “What are the investigation methods and main research findings on the manipulation of auditory feedback in voice self-monitoring of adults?”. The search protocol was based on the Population, Concept, and Context (PCC) mnemonic strategy, in which the population is adult individuals, the concept is the manipulation of auditory feedback and the context is on motor voice control. Articles were searched in the databases: BVS/Virtual Health Library, MEDLINE/Medical Literature Analysis and Retrieval System online, COCHRANE, CINAHL/Cumulative Index to Nursing and Allied Health Literature, SCOPUS and WEB OF SCIENCE. Results 60 articles were found, 19 on the Lombard Effect, 25 on the Pitch-shift-reflex effect, 12 on the Sidetone effect and four on the Sidetone/Lombard effect. The studies are in agreement that the insertion of a noise that masks the auditory feedback causes an increase in the individual's speech intensity and that the amplification of the auditory feedback promotes the reduction of the sound pressure level in the voice production. A reflex response to the change in pitch is observed in the auditory feedback, however, with particular characteristics in each study. Conclusion The material and method of the experiments are different, there are no standardizations in the tasks, the samples are varied and often reduced. The methodological diversity makes it difficult to generalize the results. The main findings of research on auditory feedback on voice motor control confirm that in the suppression of auditory feedback, the individual tends to increase the intensity of the voice. In auditory feedback amplification, the individual decreases the intensity and has greater control over the fundamental frequency, and in frequency manipulations, the individual tends to correct the manipulation. The few studies with dysphonic individuals show that they behave differently from non-dysphonic individuals.

Within-talker and within-session stability of acoustic characteristics of conversational and clear speaking stylesa).

In speech production research, talkers often perform a speech task several times per recording session with different speaking styles or in different environments. For example, Lombard speech studies typically have talkers speak in several different noise conditions. However, it is unknown to what degree simple repetition of a speech task affects speech acoustic characteristics or whether repetition effects might offset or exaggerate effects of speaking style or environment. The present study assessed speech acoustic changes over four within-session repetitions of a speech production taskset performed with two speaking styles recorded in separate sessions: conversational and clear speech. In each style, ten talkers performed a set of three speech tasks four times. Speaking rate, median fundamental frequency, fundamental frequency range, and mid-frequency spectral energy for read sentences were measured and compared across test blocks both within-session and between the two styles. Results indicate that statistically significant changes can occur from one repetition of a speech task to the next, even with a brief practice set and especially in the conversational style. While these changes were smaller than speaking style differences, these findings support using a complete speech set for training while talkers acclimate to the task and to the laboratory environment.

Contributions of temporal envelope and temporal fine structure to segregation of Lombard speech from background noise

Contributions of temporal envelope and temporal fine structure to segregation of Lombard speech from background noise

Lombard Speech Detection in Case of Spatial Separation between Noise Source and Speakers of Different Genders

Lombard Speech Detection in Case of Spatial Separation between Noise Source and Speakers of Different Genders

Acoustic characteristics of non-native Lombard speech in the DELNN corpus

Lombard speech, speech produced in noise, has been extensively studied in native speakers, while non-native Lombard speech research is limited. This article presents the first corpus of non-native Lombard speech, the Dutch English Lombard Native Non-Native corpus, which includes plain and Lombard read speech from native American-English, non-native English (native Dutch), and native Dutch women. The location of contrastive focus is systematically varied in the sentences. We investigated how intensity, spectral center of gravity, word duration, and VOT varies in the corpus as a function of plain versus Lombard speech and whether it is modulated by the speaker’s nativeness and of the language. We did not find differences in how the native and non-native English speakers adapted their English speech in noise, indicating that the Dutch non-native speakers produced Lombard speech similarly to the native English. The comparison of the native Dutch and non-native English sentences produced by the same participants nevertheless suggests that, for all acoustic measurements except word duration, the Dutch speakers adapted their Lombard speech differently in native Dutch than in non-native English. Combined, this would indicate that, when speaking English, Dutch speakers adapt their way of speaking in noise to the way native English speakers do.

Applying the Lombard Effect to Speech-in-Noise Communication

This study explored how the Lombard effect, a natural or artificial increase in speech loudness in noisy environments, can improve speech-in-noise communication. This study consisted of several experiments that measured the impact of different types of noise on synthesizing the Lombard effect. The main steps were as follows: first, a dataset of speech samples with and without the Lombard effect was collected in a controlled setting; then, the frequency changes in the speech signals were detected using the McAulay and Quartieri algorithm based on a 2D speech representation; next, an average formant track error was computed as a metric to evaluate the quality of the speech signals in noise. Three image assessment methods, namely the SSIM (Structural SIMilarity) index, RMSE (Root Mean Square Error), and dHash (Difference Hash) were used for this purpose. Furthermore, this study analyzed various spectral features of the speech signals in relation to the Lombard effect and the noise types. Finally, this study proposed a method for automatic noise profiling and applied pitch modifications to neutral speech signals according to the profile and the frequency change patterns. This study used an overlap-add synthesis in the STRAIGHT vocoder to generate the synthesized speech.

Child-Directed Speech in Noise: Testing Signal- and Code-Based Phonetic Enhancement.

Talkers adapt their speech according to the demands of their listeners and the communicative context, enhancing the properties of the signal (pitch, intensity) and/or properties of the code (enhancement of phonemic contrasts). This study asked how mothers adapt their child-directed speech (CDS) in ways that might serve the immediate goals of increasing intelligibility, as well as long-term goals of supporting speech and language development in their children. Mothers (N = 28) participated in a real-time interactive speech production/perception paradigm, in which mothers instructed their young (3- to 5-year-old) children, or an adult listener, to select the picture corresponding to a target word. The task was performed at low and high levels (56 vs. 75 dB SPL) of background noise to examine the Lombard effects of decreased audibility on speech production. Acoustic-phonetic analyses of CDS and adult-directed speech (ADS) productions of target words and carrier phrase (e.g., "Find pig") revealed that mothers significantly enhanced the mean pitch, pitch variability, and intensity of target words in CDS, particularly at higher background noise levels and for younger children. Mothers produce CDS with a higher signal-to-noise ratio than ADS. However, limited evidence was found for phonetic enhancement of the segmental properties of speech. Although increased category separation was found in the voice onset time of stop consonants, decreased vowel category separation (an anti-enhancement effect) was observed in CDS. Mothers readily enhance the suprasegmental signal properties of their speech in CDS, but not the acoustic-phonetic properties of phonemes. This study fails to provide evidence of phonetic enhancement in preschool children in a dyadic communication task under noisy listening conditions. https://doi.org/10.23641/asha.24645423.

The Effect of the Frequency and Energetic Content of Broadband Noise on the Lombard Effect and Speech Intelligibility

The Lombard effect is an unconscious reflex of speakers to increase vocal effort when disturbed by noise, aiming to enhance speech intelligibility. This study aims to evaluate the effect of noise with different energetic content and levels at various frequencies on the Lombard effect, communication disturbance, vocal comfort, and speech intelligibility. Twenty university students participated in the study, reading a six-sentence excerpt and performing an intelligibility test under 12 randomized noise conditions. These conditions included noises at low (20–500 Hz), medium (500–4000 Hz), and high frequencies (4000–20,000 Hz), at four levels (45 dB, 55 dB, 65 dB, 75 dB). After each condition, participants rated their perceived communication disturbance and vocal discomfort. The results indicated that noise with energetic content at medium frequencies produced the highest Lombard effect, produced the most detrimental effect on communication disturbance and vocal comfort, and caused the strongest decrease in speech intelligibility, whereas it was minimally affected by low- and high-frequency noise. In conclusion, this study highlights that medium-frequency noise has the greatest impact on vocal effort, communication disturbance, and vocal comfort, while low- and high-frequency noise has minimal effect on speech intelligibility.

Acoustic and articulatory modifications of Mandarin vowels in clear and Lombard speech

This study investigated the acoustic modifications of Mandarin vowels /a, i, u/ in clear speech and Lombard speech. Their underlying articulatory movements in the tongue and lips were also examined using ultrasound imaging and lip videos. Plain (i.e., conversational), clear and Lombard speech productions were elicited through a series of map tasks, where participants were prompted by pre-recorded videos to interact with the listener on the screen. Results showed that clear and Lombard speech in Mandarin resulted in longer syllable duration as well as greater vowel RMS intensity than plain speech. Spectrally, not all three vowels were modified to enhance their phonological features in response to clear or Lombard speech conditions. However, the differential F1/F2 modifications did result in an expanded vowel space. Some associations and mismatches between F1/F2 measurements and articulatory movements were observed. Particularly, greater mouth opening and lowering of tongue body in /a/ in clear and Lombard speech could account for the raising of F1. Few modifications in /i/ tongue position and lip configurations also corresponded to no significant F1/F2 change. The acoustic-articulatory relationship for /u/, in contrast, was less straightforward. These observations are discussed in relation to existing clear speech and Lombard speech literature.

Тhe role of auditory feedback in voice control with normal and impaired hearing

Control of speech fulfilled by cooperation between feedforward control and feedback control. Feedforward control activates program of articulation, whereas feedback control carries acoustic and sensorimotor information about pronounced utterance. Their complementary speech control function described by the DIVA model, which based on adjustment of auditory and proprioceptive signals relatively to program of articulation in nerve centers. The inconsistency between the sensory information received via feedback and the presentation of the acoustic signal in the auditory nucleus causes corrective commands. Auditory feedback is necessary for the correct development of children’s articulatory skills, i.e. forming feedforward control. For this reason, prelingually deafened adults have significant articulation impairments due to immature articulatory skills. In postlingual deafness, the previously forming feedforward control allows pronounce phonemes successfully. However, in people with sensorineural hearing loss, control of phonation and articulation through the auditory feedback deteriorates, which expressed by an increase of voice intensity, changes in the speech spectral characteristics and instability in frequency and amplitude. Similar speech changes are found in speakers with normal hearing in the presence of noise that masks the speaker’s voice (Lombard effect). In noise, voice intensity increase, spectral characteristics of speech shift to the high-frequency region, and increase the amplitude and speed of articulatory movements (hyperarticulation). This speech reorganization is an adaptation of the speaker’s own voice to background noise, which purpose is to unmask the speech and restore auditory feedback control.

Wind noise source level and Bio-Goose: Perspectives on Doug Cato’s contributions in ocean ambient noise

Doug Cato’s research has provided insights that form the basis of our understanding of ambient noise in the ocean. This paper focuses on only two aspects of ambient noise that are strongly linked to Doug’s work. One is source level of ambient sound due to local wind at the sea surface. Estimates of wind sound source level derived from noise measurements with vertical line hydrophone arrays are shown to be consistent with the levels for noise due to wind reported in the Cato curves—up to date relationships for levels of components of ambient noise over a wide frequency band. The second aspect revisits a curious sound that was recorded in waters around Australia and New Zealand some years ago. The sounds were believed to be generated by marine animals, but the type of creature was not identified at sea or in subsequent analysis. Owing to the limited bandwidth of the recordings, the sound was accordingly dubbed as Bio-Duck in New Zealand and Bio-Goose in Australia. Further characteristics of the sound are presented, along with evidence of a probable conversation between two speakers and an example of the Lombard effect in the communications.