Biomedical subjects

David M Howard

Publications and source records attributed to David M Howard.

13 recordsLinked to original sources

PubMed2006

The effects of a third generation combined oral contraceptive pill on the classical singing voice.

The success of professional operatic singers depends upon the quality of their vocal mechanism. This is known to be sensitive to changes in the endocrine environment. Despite a widespread belief among singers that vocal quality changes according to the stage of the menstrual cycle, this has received little attention. In particular, the possibility that use of the contraceptive pill might stabilize vocal quality by "dampening" hormonal fluctuations has not previously been studied systematically. Here, we show that drospirenone containing oral contraceptive pill (Yasmin, Schering AG, West Sussex, UK) with antiandrogenic and antimineralocorticoid properties demonstrates a significant reduction in the irregularity of the pattern of vibration of the vocal folds during the performance of highly trained classical singers. This study constitutes the first double blind, randomized placebo controlled trial to assess the effects of the contraceptive pill on the patterns of vibration of the vocal folds during the performance of Western classical singing repertoire.

Adult↗

PubMed2006

Intonation drift in a capella soprano, alto, tenor, bass quartet singing with key modulation.

OBJECTIVES/HYPOTHESIS: When a soprano, alto, tenor, bass (SATB) quartet sings unaccompanied, or a capella, the members of the group will tend to make use of non-equal-tempered intonation to govern their tuning. If the music they are performing visits different keys and they do maintain non-equal-tempered tuning, then the pitch center will have to shift from its starting point, which is a necessary consequence of the physics behind the use of a non-equal-tempered tuning system. The implication of this shift for tuning in a capella singing is that it is not possible both to maintain accurate non-equal-tempered tuning and to stay in pitch throughout music that modulates in key. METHODS: To test this notion, a set of four-part exercises were written by the author that visit several different key chords in sequential progression. In each case, the starting and finishing chords were either identical or exactly an octave apart. Mean fundamental frequency values for each note were measured using four electrolaryngographs (one per singer), and the f0 data were normalized and plotted with respect to equal-tempered tuning to enable any overall tuning shift to be observed. RESULTS: The results indicate that singers do (1) tend to non-equal-tempered tuning and (b) do consequentially shift their intonation with modulation. CONCLUSIONS: These data indicate that pitch drift is potentially a necessary part of staying in-tune. Further work is required to identify items in the choral repertoire for which this effect is likely and then to inform the choral conducting and singing communities appropriately.

Cooperative Behavior↗

PubMed2006

Are real-time displays of benefit in the singing studio? An exploratory study.

This article reports on an exploratory research project to evaluate the usefulness or otherwise of real-time visual feedback in the singing studio. The primary purpose of the work was not to optimize the technology for this application, but to work alongside teachers and students to study the impact of real-time visual feedback technology use on the students' learning experiences. An action research methodology was used to explore the benefit of real-time displays over an extended period. The experimental phase of the work was guided by a Liaison Panel of teachers and academics in the areas of singing, pedagogy, voice science, speech therapy, and linguistic science. Qualitative data were collected from eight students working with two professional singing teachers. The teachers and students acted as co-researchers under the action research paradigm. Teachers and students alike kept journals of their teaching and learning experiences. Singing lessons were observed regularly by the research team, coded for teacher and student behaviors, and all co-researchers were interviewed at the mid- and endpoint of the project. The use of technology had a positive impact on the learning process, and this is evidenced through case study data.

Equipment Design↗

PubMed2006

Nonlinear modelling of double and triple period pitch breaks in vocal fold vibration.

This paper reports a study on short-time subharmonic pitch breaks in vocal fold vibration, which are found to be a common feature of the human voice in spoken language. The observed pitch breaks correspond to a change in periodicity of the electrolaryngograph (Lx) signal. This paper presents a nonlinear dynamical system capable of producing time-series with subharmonic pitch breaks. The resulting time-series resemble closely Lx recordings of natural speech. The system is developed on the basis of a second order linear system, which is extended with a third dimension and nonlinear coupling terms. It is suggested that improved knowledge about pitch breaks could be used in future speech synthesis systems in order to improve the naturalness of the perceived output.

Female↗

PubMed2005

An exploratory baseline study of boy chorister vocal behaviour and development in an intensive professional context.

Currently, there is no existing published empirical longitudinal data on the singing behaviours and development of choristers who perform in UK cathedrals and major chapels. Longitudinal group data is needed to provide a baseline against which individual chorister development can be mapped. The choristers perform to a professional standard on a daily basis, usually with linked rehearsals, whilst also following a full school curriculum. The impact of this intensive schedule in relation to current vocal behaviour, health and future development requires investigation. Furthermore, it is also necessary to understand the relationship between the requirements of chorister singing behaviour and adolescent voice change. The paper will report the initial findings of a new longitudinal chorister study, based in one of London's cathedrals. Singing and vocal behaviours are being profiled on a six-monthly basis using data from a specially designed acoustic and behavioural instrument. The information obtained will enable us to understand better the effects of such training and performance on underlying vocal behaviour and vocal health. The findings will also have implications for singing teachers and choral directors in relation to particular methods of vocal education and rehearsal.

Adolescent↗

PubMed2005

Towards an understanding of speech and song perception.

The human singing voice plays an important role in music of all societies. It is an extremely flexible instrument and is capable of producing a tremendous range of sounds. As such, the human voice can be hard to classify and poses a major challenge for automatic audio discrimination and classification systems. Speech/song discrimination is an implicit goal of speech/music discrimination, where a division is sought between speech and song, such that the singing voice can be grouped together with other musical instruments in the same category. However, the division between speech and song is unclear and even human attempts at speech/song discrimination can be highly subjective and open to discussion. In this paper we present the results of a test that was designed to investigate differences in auditory perception for speech and song. Twenty-four subjects were instructed to attend to either the words or pitch, or both words and pitch of context-free spoken and sung phrases. After presentation of each phrase, subjects were asked to either type the words that they recalled, or select the correct pitch contour from a choice of four graphical representations, or do both, depending on the task specified before presentation of the phrase. The results of the experiment show a decrease in the amount of linguistic information retained by subjects for sung phrases and also a decrease in accuracy of response for the sung phrases when subjects attended to both words and pitch instead of words or pitch alone.

Adult↗

PubMed2005

Electrolaryngographically derived voice source changes of child and adolescent singers.

Children are the most likely demographic group to undertake regular singing or singing training, but to date there has been little quantitative research into the voice production of children. The authors used closed quotient (CQ) measurements to analyse the singing voices of over 200 male and female, trained and untrained singers aged 8-18 years for differences in voice source according to sex, vocal training and age. Results indicated that the voice source production of subjects could be clearly divided into groups according to age, sex and the level of vocal training received. It was concluded that the process of training a young voice has a quantifiable effect upon the voice source. It was also concluded that sex differences result in significant differences in the voice source of child and adolescent singers.

Adolescent↗

PubMed2005

Discussant response to 'Does the acoustic waveform mirror the voice?'.

The acoustic waveform that reaches the two ears of a listener can convey the intended message. Over the telephone, this waveform is the only source of information from the speaker, since the listener is out of visual contact; indeed, in this situation the acoustic waveform itself is restricted in its frequency content. Whilst the listener can infer much about the speaker from the acoustic waveform, including the speaker's age, gender, nationality, dialect, and emotional state, the issue under consideration here is the extent to which quantitative analysis of the acoustic waveform can provide useful information about a speaker's voice. This paper was presented as an Invited Discussant Response, at the Pan-European Voice Conference (PEVOC6) in London, to the question posed in Ternström's Invited Keynote Lecture 1: Does the acoustic waveform mirror the voice?

Humans↗

PubMed2004

WinSingad: a real-time display for the singing studio.

This paper describes the nature and implementation of a specially-designed integrated real-time display that is undergoing evaluation as part of a recently funded innovative pilot project to investigate the relative usefulness of computer displays in the singing studio. Following previous work that suggests that simple displays of a small number of analysis parameters are generally likely to be the most effective, the system makes available a range of complementary analyses that are plotted against time. These relate to: fundamental frequency, spectrum, spectral ratio, and vocal tract area. These can be viewed singly, multiply or in combination using a panel based design within the PC Windows environment, known as WinSingad. The algorithms used are described and the displays themselves are illustrated with results gained from the pilot phase of the research to indicate their potential usefulness.

Adult↗

PubMed2004

Measuring the tuning accuracy of thousands singing in unison: an English Premier Football League table of fans' singing tunefulness.

Tunefulness in singing is well understood in the context of solo stage performance, singing in small groups and singing in choirs, with or without accompaniment, and it can be readily measured under laboratory conditions. When thousands of people are singing outside in support of their football team, however, the singing is impromptu; there is no conductor, no starting note, and generally no accompaniment. This paper describes the measurement of the tunefulness of the singing of fans of the twenty clubs in the 2001-2002 English Premier League. The technique adopted is unusual in that it makes direct reference to the formal definition of pitch as a subjective phenomenon. The results are presented in the form of a 2001-2002 English Premier League football fans singing league table.

Acoustics↗

PubMed2002

Clinical pilot study assessment of a portable real-time voice analyser.

The use of computer-based real-time visual displays is now well established in voice clinics. A number of situations exist, however, where a computer-based system is inconvenient and a battery-powered hand-held version would be preferred. This would, for example, enable voice monitoring to be carried out at any time and place, including during home visits. This paper describes a purpose-built device that provides real-time displays of fundamental frequency and larynx closed quotient (CQ) derived from the electrolaryngograph output. The fundamental frequency data can in addition, be acquired from a microphone. The system has been in use recently in a speech and language therapy clinic in Sheffield, UK and the advantages and disadvantages noted during that trial are discussed.

Electric Stimulation↗

PubMedDate not supplied

The real and the non-real in speech measurements.

The measurement of parameters from the output acoustic pressure waveform during speech has been a common activity in speech science laboratories for a number of decades. The widespread availability of personal computers with more than adequate processing capability to carry out speech analysis means that speech analysis is now commonly available and many more users have access to it. Indeed, there are some highly comprehensive speech analysis software packages available for PC computers as freeware. However, the results gained from speech analysis are not always a function only of the speech input itself, as there are some often surprising pitfalls to be aware of, due to the nature of the chosen measurement technique itself. This paper explores commonly applied speech analysis techniques and focuses particularly on some potential pitfalls and their consequences.

Fourier Analysis↗

PubMedDate not supplied

Human hearing modelling real-time spectrography for visual feedback in singing training.

The traditional form of spectrography employed for speech analysis makes use of fixed bandwidth bandpass filters, which are usually set either to wide-band or narrow-band to optimise the time and frequency resolution of the resulting spectrogram respectively. The acoustic analysis carried out by the human ear can be modelled as a bank of bandpass filters whose bandwidth changes as a function of centre frequency, and therefore the time and frequency resolution varies with frequency. This paper describes a spectrographic analysis technique that is based on peripheral human hearing and considers its potential for application within a real-time visual display for singing training by comparing its output with traditional wide- and narrow-band spectrograms. The potential advantages and disadvantages of hearing modelling spectrography for this application are illustrated and discussed for a selection of sung material, some of which has been recorded during singing lessons where traditional spectrography is being employed.

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