David M Howard

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• FREng; PhD, BSc (Eng) E&E Eng, 1st Class, UCL
• Personal Chair at Royal Holloway University of London

This work develops and evaluates a self‐navigated variable density spiral (VDS)‐based manifold regularization scheme to prospectively improve dynamic speech magnetic resonance imaging (MRI) at 3 T. Short readout duration spirals (1.3‐ms long) were used to minimize sensitivity to off‐resonance. A custom 16‐channel speech coil was used for improved p...

This paper notes that accurate tuning in a cappella (unaccompanied) choral music is a two-step process requiring (1) making pitch shifts on individual notes to sing intervals in just intonation thereby pro-viding beat-free tuning for the consonant musical intervals that underpin the underlying harmony and (2)tuning different vowels to account for a...

Objectives: Pitch perception is an important part of accurate singing. Therefore, accurate singing requires the ability to accurately assess the pitch in one's own voice.There are two objectives of this study the first was to investigate whether there is a measurable difference in perceived pitch in one's voice to the pitch one perceives from an e...

Objectives MRI based vocal tract models have many applications in voice research and education. These models do not adequately capture bony structures (e.g. teeth, mandible), and spatial resolution is often relatively low in order to minimize scanning time. Most MRI sequences achieve 3D vocal tract coverage at gross resolutions of 2 mm³ within a sc...

Purpose: To improve dynamic speech imaging at 3 Tesla. Methods: A novel scheme combining a 16-channel vocal tract coil, variable density spirals (VDS), and manifold regularization was developed. Short readout duration spirals (1.3 ms long) were used to minimize sensitivity to off-resonance. The manifold model leveraged similarities between frames s...

Objectives The Vocal Tract Organ has had a number of iterations resulting from advances in available technology as well as requirements of perceptual experiments and performance paradigms. The objective of this paper is to relate the development history of the Vocal Tract Organ from the original vision to what it is today as a modern version of the...

A review of current research on vocal acoustics and acoustic registration for singers, and the author's current pedagogical approaches.

Digital signal processing (DSP) education has traditionally employed more demanding mathematics than most topics found among courses in electrical/electronic/computer engineering. In some cases, the technical challenges posed by some courses have made it difficult for students to complete those courses successfully. Here, we advocate for creativity...

Background and objectives The valleculae can be seen as a pair of side branches of the human vocal tract like the piriform fossae. While the acoustic properties of the piriform fossae have been explored in detail , there is little evidence of full exploration of the acoustic properties of the valleculae. A recent investigation (Vampola, Horáček, &...

The sound of a 3,000 year old mummified individual has been accurately reproduced as a vowel-like sound based on measurements of the precise dimensions of his extant vocal tract following Computed Tomography (CT) scanning, enabling the creation of a 3-D printed vocal tract. By using the Vocal Tract Organ, which provides a user-controllable artifici...

A novel app 'Speech Test' © davidmhoward was developed in iOS to evaluate the fundamental voice speaking frequency SF0 (Hz). It can be downloaded from the App store. A simple counting task from 20-0 backwards allows a reading of the mean voice pitch to be determined. After full ethical permission, 62 boys aged 10-17 years attending endocrinology or...

The question of how and what boys should sing during adolescent voice change has challenged educators and choir leaders for the last century. As the larynx enlarges during adolescence, most boys will follow the descending pitch of their speaking voice and move to singing vocal parts with a lower pitch range. Occasionally a boy may continue to sing...

Tuning for musical instruments without a fixed pitch and for the human voice can vary note by note. A recent investigation analysing the evolution of tuning tendencies in a semi-professional singing quintet during a four-month study period demonstrates that the ensemble tended consistently to equal temperament tuning rather than just intonation. Th...

Singing has been a characteristic behaviour of humanity across several millennia. Chorus America (2009) estimated that 42.6 million adults and children regularly sing in one of 270,000 choruses in the US, representing more than 1:5 households. Similarly, recent European-based data suggest that more than 37 million adults take part in group singing....

Objective: The skill to control pitch accurately is an important feature of performance in singing ensembles as it boosts musical excellence. Previous studies analysing single performance sessions provide inconclusive and contrasting results on whether singers in ensembles tend to use a tuning system which deviates from equal temperament for their...

The human singing voice changes throughout the lifespan and there are gender- specific variations that need to be taken into account. Life changes in terms of voice are different for females and males and this paper concentrates on the female singing voice in the context of choral singing. Case-study data from three choristers are presented relatin...

Modern personal computers are fast enough to analyze singing and provide real-time visual feedback of relevant acoustic elements. This feedback provides a quantitative dimension to the learning process in support of developing appropriate sung outputs. However, no computer-based system can replace the singing teacher, as the qualitative listening o...

The advent and now increasingly widespread availability of 3-D printers is transforming our understanding of the natural world by enabling observations to be made in a tangible manner. This paper describes the use of 3-D printed models of the vocal tract for different vowels that are used to create an acoustic output when stimulated with an appropr...

0.1. Introduction Soprano singers face a number of specific challenges when singing vowels at high frequencies, due to the wide spacing of harmonics in the voice source. The varied and complex techniques used to overcome these are still not fully understood. Magnetic resonance imaging (MRI) has become increasingly popular in recent years for singin...

The acoustics of a space can have a real impact on the sounds you create and capture. Acoustics and Psychoacoustics, Fifth Edition provides supportive tools and exercises to help you understand how music sounds and behaves in different spaces, whether during a performance or a recording, when planning a control room or listening space, and how it i...

Objective Soprano singers face a number of specific challenges when singing vowels at high frequencies, due to the wide spacing of harmonics in the voice source. The varied and complex techniques used to overcome these are still not fully understood. Magnetic resonance imaging (MRI) has become increasingly popular in recent years for singing voice...

Electronics education needs to change to meet the working needs of employers, and to expand by increasing undergraduate student numbers to help meet the shortage of engineers in the UK and elsewhere. In addition, it needs to acknowledge and provide skills guidance and experience for students in the working needs of employers specifically by making...

Introduction At the upper end of the soprano range, singers adjust their vocal tract to bring one or more of its resonances (Rn) toward a source harmonic, increasing the amplitude of the sound; this process is known as resonance tuning. This study investigated the perception of (R1) and (R2) tuning, key strategies observed in classically trained so...

This research presents the evaluation from applying a Two-Dimensional Rectilinear Digital Waveguide Mesh (2-D RDWM) to model the vocal and nasal tracts for synthesizing the three English nasal consonants /m/, /n/ and /ŋ/. The rectilinear meshing represents the propagated pressure according to the cross-sectional area at each tract position. Nasal t...

The human voice has essentially always played a part in music making; indeed, larger pipe organs have incorporated a Vox Humana stop for many years. Work on improving the naturalness of vocal synthesis using articulatory knowledge requires magnetic resonance imaging of natural vocal tract shapes and this has enabled 3-D printed models to be made. T...

Objective: The phenomenon of resonance tuning, whereby a singer modifies the shape of their vocal tract to increase the acoustic power output, is commonly exploited across large pitch ranges by professional sopranos and has been observed to a lesser degree in nonexpert adult singers. This study considers the employment of two common resonance tuni...

The menu is an important interface component, which appears unlikely to be completely superseded by modern search-based approaches. For someone who is unable to attend a screen visually, however, alternative non-visual menu formats are often problematic. A display is developed in which multiple concurrent words are presented with different amounts...

The menu is an important interface component, which appears unlikely to be completely superseded by modern search-based approaches. For someone who is unable to attend a screen visually, however, alternative non-visual menu formats are often problematic. A display is developed in which multiple concurrent words are presented with different amounts...

The English Cathedral tradition of regularly sung services is a centuries-old tradition in the UK. The upper (usually termed ‘treble’) musical line was originally sung by boy choristers, but over the past nearly quarter century, girl choristers have taken over the top line in some services. We have been recording girl choristers at Wells Cathedral...

Formant tuning is a technique seen in professional female adult singers, whereby the singer modifies the shape of their vocal tract in order to increase the acoustic power output by improving the efficiency of the vocal source and vocal tract. It has been seen that formant tuning is employed over a smaller pitch range by less experienced singers, a...

The epilarynx for any individual has dimensions that are unique to that person, and they have a direct impact on the overall acoustic output spectrum during speech and singing. In particular, it is the relationship between the dimensions of the epilarynx and those of the main vocal tract that accounts for the acoustic output from a vocal tract in r...

Scitation is the online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies

In speech/singing, knowledge of the frequencies of the resonances of the vocal tract gives access to the vowel type (lower resonances) and the voice timbre (higher resonances). It is therefore crucial to be able to measure accurately these resonant frequencies directly. Several approaches have been developed such as glottal excitation, excitation a...

David M. Howard has set out to explain choir singing in a novel way. His goal is to help choral directors get the best performance while all the time maintaining the focus that choirs only perform at their best when their voices are healthy. This book is full of tips and hints from an author who has worked in both voice research and as a choral dir...

The Vocal Tract Organ is a new musical instrument that consists of three-dimensional (3D)-printed vocal tracts (throat and mouth) for individual vowels sitting on loudspeakers to enable static vowel sounds to be produced. The acoustic excitation from the loudspeakers is a synthesized version of the typical waveform produced by the vibrating human v...

The piriform fossae are the 2 pear-shaped cavities lateral to the laryngeal vestibule at the lower end of the vocal tract. They act acoustically as side-branches to the main tract, resulting in a spectral zero in the output of the human voice. This study investigates their spectral role by comparing numerical and experimental results of MRI-based 3...

The Vocal Tract (VT) of a singer acts as a filter on the acoustic output from the vibrating vocal folds, enhancing several frequency bands whose peaks are called formants. The nature of these formants is characterized by the shape and dimensions of the VT and they are numbered with the first formant being the lowest in frequency. Perceptually, the...

Vocal synthesis has been the subject of investigation since the late 18th century when von Kempelen produced his mechanical ‘speaking machine’. The advert of electronics has enabled a number of different methods of voice synthesis to be realized in practice. Recently with the advent of 3-D printing and magnetic resonance imaging of human vocal trac...

The digital waveguide mesh has been shown to be capable of reproducing the acoustic impulse response of cylindrical vocal tract analogs. This study extends the same methodology to three-dimensional simulation of the acoustic response of graphical models of the vocal tract obtained from magnetic resonance imaging for a group of trained subjects. By...

The acoustics of a space can have a real impact on the sounds you create and capture. Acoustics and Psychoacoustics gives you an essential grounding and understanding to how real music sounds behave in different spaces whether during a performance or a recording and how they are perceived by performers and listeners. With their clear and simple st...

This first definitive reference resource to take a broad interdisciplinary approach to the nexus between music and the social and behavioral sciences examines how music affects human beings and their interactions in and with the world. The interdisciplinary nature of the work provides a starting place for students to situate the status of music wit...

This definitive reference resource examines how music affects human beings and their interactions in and with the world. The interdisciplinary nature of the work provides a starting place for students to situate the status of music within the social sciences in fields such as anthropology, communications, psychology, linguistics, sociology, sports,...

This definitive reference resource examines how music affects human beings and their interactions in and with the world. The interdisciplinary nature of the work provides a starting place for students to situate the status of music within the social sciences in fields such as anthropology, communications, psychology, linguistics, sociology, sports,...

This paper describes an innovative musical instrument known as the Vocal Tract Organ that has arisen out of research into the acoustics of singing to promote understanding and enable a new performance paradigm of the human singing voice in performance. A fundamental aspect of the research side of this endeavour is to investigate individual elements...

Objectives/hypothesis: Listeners often describe the voices of solo child singers as being "pure" or "clear"; these terms would suggest that the voice is not only pleasant but also clearly audible. The audibility or clarity could be attributed to the presence of high-frequency partials in the sound: a "brightness" or "ring." This article aims to in...

The vocal tract (VT) of a singer acts as a filter on the acoustic output from the vibrating vocal folds, enhancing several frequency bands whose peaks are called formants. The nature of these formants is characterized by the shape and dimensions of the VT and they are numbered with the first formant being the lowest in frequency. Perceptually, the...

A number of entries in this dictionary

This current work explored the speech-based attributes of participants who were being deceptive in an experimental interrogation setting. In particular, the study attempted to investigate the appropriateness of using temporal speech cues in detecting deception. Deceptive and control speech was elicited from nineteen speakers and the data was analyz...

Accurate tuning is an important aspect of singing in harmony in the context of a choir or vocal ensemble. Tuning and 'pitch drift' are concerning factors in performance for even the most accomplished professional choirs when singing a cappella (unaccompanied). In less experienced choirs tuning often lacks precision, typically because individual sin...

Mixed soft/solid models of the vocal tract were moulded with a 3D rapid prototyping technique based on MRI data obtained from two male singers during the phonation of five English vowels as in hard, stern, neap, port, and food. The replicas are used to assess the interaction of several vocal tracts in different settings: twice the same singer or tw...

Hirson and Howard present a case study and analysis of the cockpit voice recorder (CVR) from a South African Airways passenger aircraft off Mauritius on 28 November 1987.

Voice synthesis systems are now quite widespread in their application, generally for the provision of information from databases such as timetabling, stock listing, system status reports and instruction provision in hands-free situations. Today’s voice synthesis systems are usually highly intelligible but non-natural and this is the main focus of t...

The current work intended to enhance our knowledge of changes or lack of changes in the speech signal when people were being deceptive. In particular, the study attempted to investigate the appropriateness of using speech cues in detecting deception. Truthful, deceptive and control speech were elicited from ten speakers in an interview setting. The...

The goal of this study is twofold: first, to examine in greater depth the claimed contribution of differences in syllable structure to measures of speech rhythm for three languages that are reported to belong to different rhythmic classes, namely, English, ...

Although voice disorder is ordinarily first detected by listening, hearing is little used in voice measurement. Auditory critical band approaches to the quantitative analysis of dysphonia are compared with the results of applying cycle-by-cycle time based methods and the results from a listening test. The comparisons show that quite large rough/smo...

Public engagement with science, technology, and engineering is seen as being increasingly important as the numbers of school leavers choosing to read for degrees in these areas is typically dropping. Engagement with pupils during their school years is seen as being a key element in influencing their choices of career for which seeds are sown from t...

In recent years research in the three-dimensional sound generation field has been primarily focused upon new applications of spatialized sound. In the computer graphics community the use of such techniques is most commonly found being applied to virtual, immersive environments. However, the field is more varied and diverse than this and other resea...

Purpose Difficulties with intonation and vibrato control during the menstrual cycle have been reported by singers; however, this phenomenon has not yet been systematically investigated. Method A double-blind randomized placebo-controlled trial assessing effects of the menstrual cycle and use of a combined oral contraceptive pill (OCP) on pitch con...

This paper considers the measurement of voice quality variations relating to three different performance styles of early music singing by a trained soprano. In particular, the various outputs available following the collection of electrolaryngographic data are presented along with acoustic analyses based on the acoustic pressure waveform to enable...

This paper presents a study of an articulatory-based speech syn-thesis based on a 2D-Digital Waveguide Mesh (2D-DWM) to model acoustic wave propagation in the oral tract. It is employed to study the effects of changing oral tract area, and in particular, of moving the articulators during the production of diphthongs. The operation of the synthesize...

The aim of this paper is to summarise the acoustical correlates of stress in speech by reviewing relevant empirical studies. Research into speech under stress faces several challenges including the difficulty in defining the concept of stress, limitations in collecting stressed speech experimentally and the problem of quantifying the type and level...

The breadth of expression in singing depends on fine control of physiology and acoustics. In this review, the basic concepts from speech acoustics, including the source-filter model, models of the glottal source and source-filter interactions, are described. The precise control, the extended pitch range, the timbre control and, in some cases, the u...

The world of singing teaching makes use of a number of techniques to encourage student singers into the use of a proper and healthy technique in the context of whatever genre they wish to pursue. Increasingly, young singers are asking why they are not making use of technology such as computers, tablets and/or smart phones as part of their singing t...

This study explored the changes in the speech signal when people were being deceptive. Truthful, deceptive and control speech was elicited from ten speakers during an interview setting. Results are presented on parameters including f 0 , intensity and vowel formant frequencies. A significant correlation could not be established for any of the acous...

The current work sets out to enhance our knowledge of changes or lack of changes in the speech signal when people are being deceptive. In particular, the study attempted to investigate the appropriateness of using speech cues in detecting deception. Truthful, deceptive and control speech was elicited from five speakers during an interview setting....

This paper contextualises the position of speech input from a user-centred human factors perspective. It is presented as a position paper so that researchers and designers can consider the underlying and future factors of a people-orientated approach to speech input for virtual applications. A number of key areas are explored including: human facto...

In recent years research in the three-dimensional sound generation field has been primarily focussed upon new applications of spatialized sound. In the computer graphics community the use of such techniques is most commonly found being applied to virtual, immersive environments. However, the field is more varied and diverse than this and other rese...

Musicians alter their performance according to the acoustic environment in which they perform, but as yet a thorough parametric investigation of the effect of room acoustics on musical performance has not been achieved. A sufficiently "realistic" synthesized Room Impulse Response (RIR) will facilitate such a study, since this will allow the investi...

In this work, a revised form of Implicit Context Representation Cartesian Genetic Programming is used in the development of a diagnostic tool for the assessment of patients with neurological dysfunction such as Alzheimer's disease. Specifically, visuo-spatial ability is assessed by analysing subjects' digitised responses to a simple figure copying...

An experiment was conducted comparing two subject groups, each comprised of eight professional singers specializing in a genre of classical music: early music or grand opera. Electroglottography was used to consider vocal characteristics idiomatic to each genre. Whilst there are clear differences in contact quotient between subjects, particularly w...