Head-worn Microphone Research Articles

Voice acoustics and effort of three different communication scenarios presented in an anechoic baseline

While vocal pathology can elevate vocal effort, communication situations also have an effect. Previous work on vocal effort and communication situations have relied on listener ratings of effort rather than talker-centric vocal effort. Towards that end, in this study, talker-centric vocal effort was related to different communication demands. Additionally, vocal performance was measured to investigate potential relationships between effort, production, and communication demand. In an anechoic chamber, participants described to an interlocutor various maps. The communication demands were communication distance (1, 2, 4 m), loudness goal (54, 60, 66 dB), and background noise (53, 62, 71 dBA). Talkers rated their vocal effort after each task with a Borg CR100 scale and were recorded with a calibrated head-worn microphone. There were significant increases in ratings of vocal effort, fundamental frequency, intensity, and cepstral-peak prominence (CPP) from the control condition to the extremes of the distance and loudness goal vocal demands which are consistent with previously observed Lombard responses. This study shows that communication demands that exceed typical conditions (such as talking at 4 m) result in increases in vocal effort and a Lombard-like response. Therefore, considerations to potential communication barriers are important for the reduction of vocal effort.

Enhancing binaural rendering of head-worn microphone arrays through the use of adaptive spatial covariance matching.

In this article, the application of spatial covariance matching is investigated for the task of producing spatially enhanced binaural signals using head-worn microphone arrays. A two-step processing paradigm is followed, whereby an initial estimate of the binaural signals is first produced using one of three suggested binaural rendering approaches. The proposed spatial covariance matching enhancement is then applied to these estimated binaural signals with the intention of producing refined binaural signals that more closely exhibit the correct spatial cues as dictated by the employed sound-field model and associated spatial parameters. It is demonstrated, through objective and subjective evaluations, that the proposed enhancements in the majority of cases produce binaural signals that more closely resemble the spatial characteristics of simulated reference signals when the enhancement is applied to and compared against the three suggested starting binaural rendering approaches. Furthermore, it is shown that the enhancement produces spatially similar output binaural signals when using these three different approaches, thus indicating that the enhancement is general in nature and could, therefore, be employed to enhance the outputs of other similar binaural rendering algorithms.

Speech level parameters in very low and excessive reverberation measured with a contact-sensor-based device and a headworn microphone.

This work deals with the effect of very low and excessive reverberation on speech sound pressure levels. Measurements were carried out in a semi-anechoic and reverberant room using a contact-sensor-based device fixed at the base of the neck and a headworn microphone placed at 2.5 cm from the speaker's mouth. Speakers produced short monologues and also described a map with the intent of correctly explaining directions to a listener 6 m away. A significant increase of about 2 dB in mean, equivalent, and mode speech levels in semi-anechoic compared to reverberant room was on average observed for the map description from recordings with the contact device, thus, highlighting an increased vocal intensity in dead rooms when the speech task had a communicative intent. Such reliable results were not found with the headworn microphone because speech levels were affected by noise recorded in the pauses. Particularly, the 30 ms logging interval brought to more severe errors in mode and mean speech levels compared to 1 s. When the pauses were removed and a logging interval of 30 ms was adopted, results were more consistent with those obtained with the contact sensor, but level differences between the two rooms still remained not significant.

Speech sound pressure level distributions and their descriptive statistics in successive readings for reliable voice monitoring

Due to the high prevalence of voice disorders among teachers, there is a growing interest in monitoring voice during lessons. However, the reliability of the results is still to be deepened, especially in the case of repeated monitoring. The present study thus investigates the speech Sound Pressure Levels (SPL) variability under repeatability conditions aiming to provide preliminary normative data for the results assessment. In a semi-anechoic chamber, 17 subjects read twice and subsequently two phonetically balanced passages, which were simultaneously recorded with a sound level meter, a headworn microphone, and a portable vocal analyzer. Each speech sample was characterized through the distribution of SPL occurrences and several descriptive statistics of SPL distribution were calculated. For each subject, statistical differences between the two SPL distributions related to each passage were investigated using the Mann-Whitney U-test. For each group of subjects using the same device, the Wilcoxon signed-rank test was applied to the paired lists of descriptive statistics related to each passage. For mean, mode, and equivalent SPL, the within-speaker and the within-group variability were assessed for each device. For all the devices and SPL parameters, the within-speaker variability was not higher than 2 dB while the within-group variability reached 5.3 dB.

Sound Source Localization Algorithm for Low-frequency Signal's Diffraction Path Based on a Head-worn Microphone Array

Sound Source Localization Algorithm for Low-frequency Signal's Diffraction Path Based on a Head-worn Microphone Array

An Analysis of Factors Involved in Nicknaming of Some Soccer Players in South Africa

The aim of this paper is to discuss the meaning and relevance of the nicknames given to soccer players in the Premier Soccer League in South Africa, either as a token of appreciation or disapproval. The argument raised in this paper is that there is a marked deterioration in the creative naming of nicknames in the contemporary dispensation unlike in the past. It argues that nicknames have an influential role on the manner in which the players perform their duties in the field of play. The recordings of the interviews were made into a Marantz PMD-661 field recorder using a WH-30 Shure head worn microphone in a quiet room with a sample of ten people. The result shows that soccer stars are given nicknames either by coaches, teammates or by fans. These players are famously known by their nicknames, rather than their personal first names.

Voice acoustic profile of males exposed to occupational infrasound and low-frequency noise

Background: Vibroacoustic disease (VAD) is a systematic pathology characterized by the abnormal growth of extra-cellular matrices in the absence of inflammatory processes, namely collagen and elastin, both of which are abundant in the basement membrane zone of the vocal folds. VAD can develop due to long-term exposure to infrasound and low-frequency noise (ILFN, < 500 Hz). Mendes et al. (2006, 2008 and 2012) revealed that ILFN-exposed males and females presented an increased fundamental frequency (F 0 ), decreased jitter %, and reduced maximum phonation frequency range, when compared with normative data. Temporal measures of maximum phonation time and S/Z ratio were generally reduced. Study Aims: Herein, the same voice acoustic parameters of 48 males, 36 airline pilots and 12 cabin crewmembers (age range 25-60 years) were studied, and the effects and interaction of age and years of ILFN exposure were investigated within those parameters. ILFN-exposure time (i.e. years of professional activity) ranged from 3.5 to 36 years. Materials and Methods: Spoken and sung phonatory tasks were recorded with a DA-P1 Tascam DAT and a C420III PP AKG head-worn microphone, positioned at 3 cm from the mouth. Acoustic analyses were performed using KayPENTAX Computer Speech Lab and Multi-Dimensional Voice Program. Results: Results revealed that even though pilots and cabin crewmembers were exposed to occupational environments with distinct (ILFN-rich) acoustical frequency distributions and sound pressure levels, differences in the vocal acoustic parameters were not evident. Analyzing data from both professional groups (N = 48) revealed that F 0 increased significantly with the number of years of professional activity. Conclusion: These results strongly suggest that the number of years of professional activity (i.e. total ILFN exposure time) had a significant effect on F 0 . Furthermore, they may reflect the histological changes specifically observed on the vocal folds of ILFN-exposed professionals.

The effects of ILFN-exposure on voice acoustic parameters of commercial cabin crewmembers

Background: Long-term exposure to infrasound and low frequency noise (ILFN <500 Hz, including infrasound) can lead to the development of vibroacoustic disease (VAD). VAD is a systemic pathology characterized by the abnormal growth of extracellular matrices in the absence of inflammatory processes, namely of collagen and elastin, both of which are abundant in the basement membrane zone of the vocal folds. ILFN-exposed workers include pilots, cabin crewmembers, restaurant workers, ship machinists and, in previous studies, even though they did not present vocal symptoms, ILFN-exposed workers had significant different voice acoustic patterns (perturbation and temporal measures) when compared with normative population. Study Aims: The present study investigates the effects of age and years of occupational ILFN-exposure on voice acoustic parameters of 37 cabin crewmembers: 12 males and 25 females. Specifically, the goals of this study are to: 1) Verify if acoustic parameters change over the age and years of ILFN-exposure and 2) Determine if there is any interaction between age and years of ILFN-exposure on voice acoustic parameters of crewmembers. Materials and Methods: Spoken phonatory tasks were recorded with a C420 III PP AKG head-worn microphone and a DA-P1 Tascam DAT. Acoustic analyses were performed using KayPENTAX Computer Speech Lab and Multi-Dimensional Voice Program. Acoustic parameters included speaking fundamental frequency, perturbation measures (jitter, shimmer and harmonic-to-noise ratio), temporal measures (maximum phonation time and s/z ratio) and voice tremor frequency. Results: One-way ANOVA analysis revealed that as the number of ILFN-exposure years increased male cabin crewmembers presented significant different shimmer values of /i/ as well as tremor frequency of /u/. Females presented significantly different jitter % of /i, a, ɔ/ (p <0.05). Lastly, Two-way ANOVA analysis revealed that for females, there was a significant interaction between age and occupational ILFN-exposure for voice acoustic parameters, namely for jitter's mean for /a, ɔ/ and shimmer's (%) mean for /a, i/ (p <0.05). Discussion and Conclusion: These perturbation measure patterns may be indicative of histological changes within the vocal folds as a result of ILFN-exposure. The results of this study suggest that voice acoustic analysis may be an important tool for confirming ILFN-induced health effects.

Progression of dysprosody in Parkinson's disease over time—A longitudinal study

Parkinsonian speech or hypokinetic dysarthria results from a multidimensional impairment of phonation, articulation, and prosody. Although the dysprosody in Parkinson's disease (PD) is well described (alterations in speech rate and pause time, speech intensity and pitch variation), little is known about alterations of these single prosodic parameters over a longer time course. The objective of this study is to analyze changes of speech rate and pitch variation in patients with PD over time and to compare these findings with healthy controls. Patients with PD (N = 50; 27 male and 23 female) and n = 50 age-matched healthy controls (25 male, 25 female) were tested and retested after at least 7 months (mean: 25.02; median: 21; SD: 17.44; range: 7-79 months). In the PD group, motor impairment according to UPDRS motor score was similar at first and second visit. The participants had to accomplish a standardized four sentence reading task. The acoustical analysis was performed using a standard head-worn microphone for voice recordings and commercial audio software (WaveLab). For the determination of intonation based upon fundamental frequency (F(0)) variation, we used a computer analysis program (Praat). Articulatory velocity was determined by measurement of syllable rate and pause ratios. In the PD group, total speech rate (syllables per second related to total speech time/TSR) and net speech rate declined from first to second examination, especially in the male patients, but showed no significant differences to the control group. The course of pitch variation revealed some gender particularities. Whereas female patients' pitch variability declined over time, male patients' intonation variability remained relatively stable. F(0) variation in male and female patients with PD were significantly reduced compared with the control group in the first examination and the follow up as well. Progression of prosodic impairment over time showed no correlation to disease duration or UPDRS motor score. Some aspects of dysprosody in PD show characteristic changes over time, but show no clear correlation with general motor impairment as assessed by UPDRS motor score. Therefore, we suspect that the underlying mechanism could be independent from dopaminergic deficits.

Hearing-Aid Design and Evaluation for a Presbycusic Patient

An octogenarian male with gently sloping audiograms with average hearing threshold levels (0.5, 1.0, 2.0 kHz) of 56 dB was tested extensively with a two-channel master hearing aid. Each channel includes a headworn microphone and a button receiver in a fitted earmold. The electronics consist of laboratory-quality amplifiers and 13-octave-band equalizers. Speech-reception tests were conducted in an acoustically absorbent room with a closed set of 100 monosyllables presented live by a female talker in quiet and noise. In a single mini-experiment, three or four frequency responses were compared in two to four sessions of 1 hour with a counterbalanced and randomized design that allowed frequent rest periods. When the field-to-eardrum transfer function is matched in the hearing-aid over a bandwidth of 6.5 kHz, reception of monosyllables is superior to competing curves by 6%–15%. Competing curves have included: those of a good quality commercial hearing aid; high-frequency pre-emphasis of +8 dB/octave defined at the eardrum ; curves with less than +18 dB relative gain in the 2–4 kHz region; curves with bandwidth less than 6.5 kHz; and so on. Finally, it is suggested that the role of frequency distortion in the design of hearing aids may be understood by relating aided and unaided audibility curves for sound fields to measures of speech reception.