The Low Mandible Maneuver and Its Resonential Implications for Elite Singers

The Low Mandible Maneuver and Its Resonential Implications for Elite Singers *,†,‡Angelika Nair, *,†Garyth Nair, and §Gernot Reishofer, *yzNew Jersey, and xGraz, Austria Summary: Many elite singers appear to frequently drop the posterior mandible while singing to optimize resonance production. This study investigated the physiology of the Low Mandible Maneuver (LMM) through the use of magnetic resonance imaging (MRI), ultrasound (US), and spectrographic analysis. The study of elite singers has been hampered by the paucity of internal imagery. We have attempted to address this problem by using portable US equipment that we could transport to the homes, studios, or dressing rooms of such ranking singers. With the US and acoustic data gathered in fairly brief sessions, we were able to ascertain the resonance gains garnered from the technique’s use. The study featured two phases: I—MRI study of the maneuver and its physiological effect on surrounding structures (in collaboration of the Medical University of Graz, Austria) and II—US investigation that studied tongue shape during the maneuver. The LMM has significant ramifications for resonance production by enabling a concomitantly lowered larynx and increased resonance space in the pharyngeal and oral cavities. Measurements of the LMM ranged between 0.7 and 3.1 cm and showed a boost in the first harmonics as well as an enhancement in the singers formant. Its use also has a rather significant effect on the tongue shapes required for all sung phonemes. The advantage of using US for this study was the ability to produce real-time videos of the singer in action and then, through the use of stop action, precisely study both individual phoneme production and phoneme-to-phoneme transitions during the LMM. Key Words: Ultrasound–Resonance production–Tongue shapes–Biofeedback. INTRODUCTION Internal imagery of classical singers The biggest challenge of voice research is the acquisition of internal imagery without using an invasive method. This research study is designed to increase our knowledge of human vocal resonance—specifically our knowledge concerning the vocal production of those singers who inhabit the highest realms of classical singing—the elite singers. But, it is also based on a philosophy and passion, shared by the authors of this article—to do voice research with direct application into the voice studio. The authors would like to take a moment to define ‘‘elite’’ singers. These singers are members of that rarefied confraternity occupied by those who sing in the major opera houses and concert halls on a truly international basis, for example, van Dam, Pavarotti, Kaufmann, Hvorostovsky, Sutherland, Horne, Baker, Netrebko, Fleming, Garan
ca, just to name a few. Furthermore, our definition refers to those singers who have sustained at least 10 years at the top rank. This second, durational test of a singer’s rank automatically assumes that these singers possess a technique sufficient to produce the power and tone required by the Western classical operatic style while remaining vocally healthy throughout the duration of their careers. Although studies that involve low-rank professional singers have produced valuable information, their techniques are sometimes less convincing. From videos, we see evidence Accepted for publication March 18, 2015. From the *Pro Voce, Chatham, New Jersey; yDrew University, Music Department, Madison, New Jersey; zCollege of Saint Elizabeth, Music Department, Morristown, New Jersey; and the xClinic for Radiology, MR Physics, Medical University of Graz, Graz, Austria. Address correspondence and reprint requests to Angelika Nair, 420 River Road Apt. C-2, Chatham, NJ 07928. E-mail: [email protected] Journal of Voice, Vol. -, No. -, pp. 1-20 0892-1997/$36.00 Ó 2015 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2015.03.010

for a remarkable unity in the techniques of elite singers, no matter where or when they were trained. Although there have been multiple studies on vocal resonance1–7 in speech and singing, we suspect that there is a resonance-creation strategy practiced by elite singers that has received little or no study. Specifically, we are investigating a resonance-enhancing effect produced by a use of the mandible that is far from speech norms—the Low Mandible Maneuver (LMM; Figure 1). Sundberg8 reported that the ‘‘singer’s formant’’ (Fs) is imperative for the singer to be heard above an orchestra. Recent studies showed that the enhancement in the range of 2.0–3.5 kHz was related to voice quality and resonant voice, respectively.9,10 With the LMM, we expect an overall enhancement of the first harmonics and the Fs especially. Because elite singers are difficult to get into a laboratory or hospital for internal imagery, this maneuver has not been explored. However, there is visual and aural evidence available for the existence of the LMM. The authors have spent countless hours studying videos of elite singers while paying close attention to the visual and aural evidence they afford. As a result, we have compiled a listing of such external clues, including (1) far higher percentage of mouth opening during sung passages than singers of lesser rank11; (2) visible evidence of a lowered posterior mandible (the angle of the ramus); (3) where visible, the laryngeal prominence (the protruding Adam’s apple) reveals a consistently low larynx; and (4) less visible evidence of superficial tension in the lower neck region. In addition, both authors of this study have extensive professional singing experience and have been trained in the use of the LMM technique.

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FIGURE 1. MRI images from phase I of our LMM study which illustrate the Low Mandible Maneuver—left image, speaking /i/ and the right image, singing /i/ with full classical resonance. MRI courtesy of the Medical University of Graz, Austria.

Finally, in interviews with other singers and in looking for clues in published interviews involving elite singers, the LMM principle is mentioned although it does not have an ‘‘official’’ name, as yet. Current state of research in classical singing Although there has been abundant scientific research on the ‘‘acoustic’’ (aural) ramifications of classical singer resonance production, the anatomical and ‘‘physiological’’ elements have not been particularly well explored. To fully understand the physical aspects of the art, we need top-grade internal imagery (magnetic resonance imaging [MRI], computerized axial tomography [CAT], and ultrasound [US] images) demonstrating how a singer’s pharyngeal and oral spaces can be manipulated to produce the extraordinary sounds we enjoy in the concert hall and the opera house. However, we only rarely find such high-level internal imagery in the scientific literature. This rarity becomes more pronounced as one moves up through the professional ranks of classical singers. By the time we arrive at elite singers, we find absolutely no imagery on which to base our understanding of how they produce their amazing sounds. Thus, we are left with an incomplete picture. This research study is designed to acquire imagery from those singers who have received the least scientific attention because of their relative inaccessibility: elite singers. It is hoped that the collection of such imagery might add to our scientific knowledge of the physioacoustics of resonance creation of the highest level and ultimately lead to the creation of a resource that may enlighten pedagogic approaches for all singers, not just those of the highest rank. Reasons for the dearth of internal imagery Most of the voice research is being done on students or low-rank professionals. There are two principal reasons for the dearth of internal imagery of classical singers’ vocal apparatus in action:

Problems with various image-collection modes. X-ray and CAT Scan Radiation Exposure. The most commonly used technologies for obtaining internal images involve the use of radiation: x-ray and CAT scans. If we were to use x-ray with a goal of assembling a catalog of images for all phonemes, the subjects would have to endure radiation exposure ‘‘far’’ in excess of allowable norms (morally, ethically, and legally). With CAT scan, although techniques are available to drastically reduce the radiation exposure produced during x-ray use, the resulting images do not match the clarity of MRI. MRI—Three Problems. Although MRI provides us with the sharpest view of the anatomical structure of the singer’s vocal mechanisms, there are three drawbacks to this mode of imagery. Static Imaging Often Requires the Subject To ‘‘Freeze’’ the Vocal Mechanism. Standard MRI avoids the radiation exposure but has its own significant drawback because it often requires the subject to hold still for the entire time it takes the machine to capture an image. Because of this ‘‘freezing’’ of anatomical structures during the utterance of a phoneme, the use of MRI can be highly susceptible to unwanted artifacts. Moving MRI (at up to 60 fps) is now possible and would be an ideal method for studying the questions presented by this proposal. However, at the time of this study, such facilities are rare and extremely costly. Cost. Normally, the cost of obtaining the number of images needed for this study using standard MRI would be prohibitive. However, thanks to the generosity of our colleagues at the Medical University of Graz (Austria), this drawback has been overcome during phase I of the study. Gravity-Induced Artifacts. Singing is executed in an upright position but most MRI is done in a supine position. This fact might induce a degree of tissue distortion because of gravitational effects. Although a recent study on tenors showed that a supine position has a rather small effect on the vocal tract12 and that the tongue was more posterior on the supine than upright position, it had no significant

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FIGURE 3. The spectrum of Western singing styles with those closest to the norms of speech on the left and the non–speech-like resonance norms on the right. Also, to avoid a possible confusion of terms, please note the difference between rehabilitated versus rehabituated. Power. The classical singing style requires power sufficient to fill large venues (routinely seating more than 1000 listeners) without the aid of electrical amplification. Additionally, these singers must often sing over the accompaniment of full orchestra.

FIGURE 2. Phase I imagery from Graz—overlay of an ultrasound image (light gray) tongue shape (/i/) and an MRI done in the prone position to account for the potential gravitational artifacts in the MRI imagery. Image from our collaboration with the Medical University of Graz, Austria. phoneme effect.13 In phase I of this study, by performing the same protocol using both MRI (subject supine) and US (subject upright), we can correlate the two image modes to ascertain the degree of gravity-induced artifacts in the MRI imagery (Figure 2).

Tone. In addition to this requirement for vocal power, the classical performing tradition demands a tonal richness that is simply not found in the norms of everyday speech. To satisfy this additional demand, singers must maximize the resonance (internal space) available to their voices during every note, loud or soft, high or low, all while clearly enunciating a variety of languages. An interesting clue regarding just how far this style sits from the norms of the singers’ own speech is the fact that it is a universal dictum that the most difficult language for anyone to sing well is his/her own native language. This is because it is so difficult to break the fetters of one’s own speech habits, a corpus of neuromuscular instructions that have been habituated through countless hours of talking during the singer’s lifetime.

Elite singers’ professional schedules. As mentioned above, previously published imagery has been obtained mostly by using singers who have sufficient free time to both travel to the laboratory and hospital as well as devote the time for the acquisition of the images once on site. This virtually compels the use of students and singers of local or regional rank. Elite singers must endure hectic continent-spanning schedules that rarely permit extended image sessions in either laboratories or hospitals. They also do not have the desire or interest because they know already how it works and what they have to do. As a result, this rarefied population is not well studied. Had elite singers been available for internal imagery collection, the LMM resonance-creation strategy at the heart of this study may have been well documented by now. It is time to remedy that situation.

Range. Finally, the classical singer is expected to thrill audiences with that power/tone combination from the very lowest to the very highest notes that the singer’s anatomy and physiology can provide. The pitch range in which he or she is expected to sing is extreme by most other stylistic standards. Combined, these demands can seem almost superhuman, and classical singers must accomplish this day after day, night after night, without overstressing or injuring their vocal folds or attendant musculature. The classical singer must significantly increase his/her resonance volume to achieve the tone and power needed for the style in which he or she performs. Aside from the genetic endowment of the singer, many of the trainable technical advances in the singer’s technique arise from enhancing the volume of the resonance areas of the voice in the oral cavity and the pharynx. This study investigates how the vocal resonance space is being manipulated in size and shape.

Elite singers use highly refined resonance creation techniques The higher one goes in the ranks of classical singers, the more you will find a refined use of resonance creation techniques that are far more consistent, universal (in a phonemic sense), and highly habituated than the average classical singer. The classical singer inhabits a phonetic world far removed from speech norms (Figure 3). Because of the demands of the style, a massive retraining of the neuromuscular phonetic instructions is required and involves mastery in three key areas:

Vocal resonance space When our vocal folds vibrate during speech and song, they produce a very soft, dull sound (some have described it as a faint ‘‘buzz’’ on pitch). The weak nature of this initial sound makes it difficult to identify it as recognizably human—certainly not what we would call a ‘‘voice.’’ It is only when that tiny, buzz-like laryngeal signal travels up through the pharynx and oral cavity that a recognizable human voice ensues. During its travel through the vocal tract

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FIGURE 4. The resonance spaces in the supraglottal vocal instrument. (Note that the velopharyngeal port is shown closed because most phonemes require the nasal space to be removed from the resonance system.) Illustration by Garyth Nair.

(Figure 4), the laryngeal signal is greatly amplified and enriched. All qualitative acoustic values that enable our enjoyment of any voice—speaking or singing—derive from this effect of resonance. The body structures that enclose our resonance airspace are remarkably plastic. Our ability to manipulate these structures enables us to vary our vocal sounds to produce all language, all tone quality and, in fact, even the emotional content of our linguistic message. Not all classical tone is created equal When one goes through the hallway of a conservatory, one hears a singer warming up in a voice studio—the voice sounds glorious, rich, and resonant. However, if one walks past that same studio later when the singer is working on a song, most often one cannot believe that it is the same singer! Where did his/her wonderful voice go? HYPOTHESIS Low mandible maneuver We believe that the mandible use and its maintenance during phonation and throughout a singers registers, respectively, may be a principal factor in the tonal success of elite singers. Because most warm-ups are vocalises involving only vowels, the singer’s vocal production is unencumbered by the demands of consonants. This frees the singer to concentrate on LMM production of the warm-up vowels and, as a result, they sound wonderful. However, while singing a song that must contain all phonemes, the consonants are being added. Because the consonants are produced at a speech speed, the brain turns to ‘‘speech instructions’’ in the background processing. But, classical vowel resonance space cannot be maintained with the interjec-

FIGURE 5. An MRI overlay of the TMJ of the singer at rest (red) and performing the LMM (green). The LMM condyle position of a sung [ɑ] is indicated by the arrow. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.) Image from our collaboration with the Medical University of Graz, Austria.

tion of poorly produced speech consonants. In consequence, the singer loses his or her beautiful sound. Definition When we are talking about LMM, we are referring to a maneuver on the basis of the ‘‘first 10%’’ of the yawn sequence in which the entire mandible platform drops. It also creates significant additions to (1) oral space (2) pharyngeal space (hyoid/larynx drops with the mandible lengthening the pharynx)

FIGURE 6. Diagram showing the anatomic components of the TMJ. Illustration by Angelika Nair.

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FIGURE 7. Two jaw-opening paradigms. The two skulls at the top show the mandible at rest in its normal configuration (l) and the mouth opened (r). The bottom skulls show the LMM in operation with the condyle dropped (l) and the resulting increase in mouth opening and oral resonance that results from the maneuver. Illustration by Garyth Nair. Figure 5 shows two MRI images that have been overlaid. The red line shows the temporomandibular joint (TMJ) of the singer at rest, whereas the green line shows the singer performing the LMM. The condyle position both at rest and with LMM can be observed by the yellow line (image from our collaboration with the Medical University of Graz, Austria). LMM physiology The TMJ is one of the most complex joints in the body, providing a hinging and gliding movement at the same time. Figure 6 shows how the articular disc separates the condyle from the mandibular fossa. Between the condyle and the disc is the inferior joint cavity. This is also where the first part of mouth opening occurs via pure rotation of the condyle. Speech The action of the jaw during speech is envisioned as a ‘‘lever’’ where the fulcrum point is at its connection to the skull, the TMJ.

When one speaks, the condyle rotates mostly in the mandibular fossa (hinge motion) with a relatively stable jaw and minimal vertical tongue motion (see the top two skull illustrations in Figure 6). For loud speech, there occurs a minor translation along the articular eminence (also, articular tubercle). From this relatively high mandible position, there is not much resonance space available in the oral cavity.

Singing—LMM adds an additional maneuver LMM, however, consists of two interconnected, simultaneous actions (see lower two skulls in Figure 7). Once the condyle reaches the end of the first part of the mouth opening (25 mm), it now starts to translate (a movement of a body in the same direction and at the same rate) over the superior joint cavity (space between the disc and mandibular fossa) out of the fossa into the articular eminence (50–60 mm).14 In summary the two actions are:

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it is no longer anchored in the TMJ. Even without any additional mouth opening, this maneuver yields more oral space (Figure 8). Thus, the first 10% of a yawn creates:

FIGURE 8. Close up of the downward and forward drift of the

(1) Oral cavity resonance space potential—enabling optimal mouth opening (2) Pharyngeal resonance space potential—we are measuring between 1 and 2.5 cm of laryngeal drop, which elongates the pharynx and may have a factor in Sundberg’s 6:1 ratio for singer’s formant.1 (3) A possible widening—we suspect—of the top of the oropharynx because of the forward mandible movement during the LMM movements.

condyle to the bottom of the articular eminence.

(1) A drop of the ‘‘entire mandible,’’ not just the anterior portion as is experienced in most speech norms. Imagery from phase I of our study clearly shows the TMJ changes necessary for LMM (Figure 5—the LMM condyle attitude is denoted with the arrow). This condyle motion is similar to that which occurs during the first phase of a yawn. In pedagogy, there is some debate concerning the use of the yawn as a means of inducing more resonance in a classical singer’s technique. One benefit of our study will be commentary— with backup imagery—to support the use of the beginning of the yawn maneuver as a pedagogical tool and refute those who inveigh against it. (2) From that lower LMM posterior mandible position, the jaw is then used mostly as it is in speech, as a lever although

Mandibular function also includes, but is not limited to, muscles of mastication. During mastication, three muscles of mastication (or musculi masticatorii) are responsible for adduction of the jaw, and two (the superior and inferior lateral pterygoid) help to abduct it. All five move the jaw laterally. Other muscles, such as the sternocleidomastoid and the posterior cervical muscles, play a major role in stabilizing the skull and allowing a controlled movement of the mandible (Figure 9). Previous studies investigated the effects of articulatory configuration in singers’ resonance. In 1997, Sundberg and Skoog15 measured jaw opening by means of mangnetometer equipments and found that the jaw opening seems to be an important, though not the only, tool for singers to avoid F0 exceed F1. With the application of dynamic real-time MRI, recent studies tried to continue the examination of vocal tract

FIGURE 9. Head and neck muscles anatomy. Illustration by Angelika Nair.

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The LMM and Its Resonential Implications for Elite Singers

modifications in register transitions in male singer6 and the vocal tract in female registers.7 Among others, both studies showed substantial changes in the jaw opening once F0 reached the vicinity of F1. Thus, it appears that the use of jaw opening was unanimously found to be applied once F0 reached the vicinity of F1. Hence, preparing a register equalization in male and female passaggi. Story et al16 investigated various voice qualities, such as ‘‘yawny’’ and found an increase in vocal tract volume through lengthening the vocal tract and widening the oral cavity, confirming the ‘‘yawn’’ as a manipulation to achieve greater space and lower the larynx. The biomechanics of the TMJ is a finely tuned dynamic balance among all the head and neck muscles. As a person yawns, the head is brought back by contraction of the posterior cervical muscles, which raises the maxillary teeth. This simple example not only demonstrates that singing is solely orientated on the first part of a yawn (avoiding a hyperextension of the skull) but also demonstrates that even normal functioning of the masticatory system uses many more muscles than just those of mastication. With an understanding of this relationship, one can see that any effect on the function of the muscles of mastication also has an effect on other head and neck muscles (and vice versa) and ultimately the larynx. Further studies on the complex orchestration of extrinsic neck and head muscles and their influence on the larynx, tongue, and so forth may reveal more of the biomechanics and ultimately the techniques used in classical singing. The potential benefits of the use of LMM are that it:

specifies the description of the sensation for the proper open throat and laryngeal position in the middle voice as the first stage of a yawn, and that an expanded throat sensation must always be accentuated as the pitch is raised. Vennard19 addresses the necessity of ‘‘The Loose Jaw’’ for better results in even more anatomical detail. A theory on the use of LMM, open mouth, relaxed ramus of the mandible, the lower larynx, throughout all registers and the concomitant rehabituation of vowels and consonants, respectively was proposed in articles from Denver,11 Salzburg20 and the book, The Craft of Singing21 by Garyth Nair. Last but not least, all the empirical visual/ audible evidence of its use by elite singers, whether live or on video, exhibits a remarkable technical unanimity.

(1) produces the classical singer’s richest, most harmonicladen tone (clear enhancement of all upper partials and the Fs, respectively). (2) indicates the singer’s rank because the tone and diction produced by LMM results in the consistency of ‘‘all’’ phonemes, not just vowels; and (3) may be a possible factor in career longevity (impressionistic and experiential assumption that would need to be analyzed with studies of singer careers; longitudinal follow-ups or retrospective analyses would have to be conducted).

Ad phase I Phase I of the pilot study was conducted in Graz, Austria, in January 2013 and was constituted of five participants, all of whom are professional singers with considerable performance experience as opera and concert soloists (Table 1). The same protocol was used for both modes of imagery:

METHODS Our study is divided in 2 phases: I‘‘Pilot study with regionally ranked singers’’ in which we used both MRI and US, refined imaging methods and protocols, and studied biomechanics of high-level resonance production. II‘‘Internal imagery of elite singers’’ to investigate biomechanics of high-level resonance production. This phase of the study is still a work in progress and will attempt to ascertain the prevalence of LMM in the technique of elite singers.

(1) Subject at rest (2) Swallow to locate the echo of the palate (primarily for US) (3) [ɑ]—[i] toggle three times  speaking  singing (on a single pitch) (4) Italian phrase  speaking  singing (on a single pitch)

The evidence of LMM can be found in various pedagogical literatures. Garcia17 uses descriptions such as the ‘‘natural fall of the jaw’’ and ‘‘jaw should be dropping loosely,’’ respectively as a general preparation for emitting the voice. Appelman18 TABLE 1. Subjects Demographics Subject No. 1 2 3 4 5*

Voice

Age

Number of Years Study

Number as Professional/y

Number of Performances/y

Mezzo-sopr. Basso cant. Baritone Baritone Soprano

37 69 53 61 25

8 8 8 8 8

15 40 25 40 7

<20 <10 <40 <50 <50

* Unfortunately this participant got sick and could not participate in the ultrasound protocol.

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(5) Native language phrase (Native language was included to see if there are differences induced by the participant’s speech template. However, because the goal of this article was to first show the LMM in singing in general, this aspect will form part of another article in which the main focus will be the consonants in singing.)  speaking  singing (on a single pitch) The following two modes of imagery have been used:

Ultrasound The device used for this mode of imagery was a GE Logiq 7 with 30 frame rates per second (misses most fast consonant tongue actions), a GE 3S transducer, the HATS-ProVoce (stabilizes distance from the transducer to palate), and the Standoff (to allow mandible platform drop). Before the session, the subjects were asked to choose a phrase in Italian and their Native language. For the sung part of the vowels and phrases, the singers were asked to choose a comfortable pitch. Principals. An US relies on piezoelectric crystals—found in the transducer—that emanate ultrahigh-frequency sound waves and produce an image by using their reflective properties. Both the tongue surface and the hard palate can be imaged in real time using US22 (Figure 10). EdgeTrak. The software program EdgeTrak23 uses a sophisticated algorithm that searches through the noise (reflections of the sound waves) of the US and determines where the edges of the sagittal tongue profile are located (Figure 11). Mapping and fixing the position of the hard palate. Before beginning the US data collection protocol, the subject is asked to drink a bolus of water. On the US image, the US signal reflected by the thin layer of water between the top of the tongue and the hard palate reveals its precise location. Once that stable hard palate position has been obtained, it can be superimposed on all subsequent images for that subject under study and allows accurate measurement of the jaw elevation during the production of all phonemes (Figure 12).

FIGURE 10. Sagittal view of a US image. Illustration by Angelika Nair.

FIGURE 11. EdgeTrak software capturing the edge of the sagittal tongue profile (red line) as well as the hard palate (yellow line). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Head and transducer stabilization. For utilization as a research tool, the relativity between the US transducer and the subject’s head must be stabilized while still allowing for vertical mandible movement above the US transducer through the use of a device called a Head and transducer stabilization (HATS). In the lead-up to the image collection in phase I, we were able to test and refine our HATS system for use during US data collection (Figure 13). In-laboratory HATS systems are generally quite large, heavy and very nonportable. However, because this project calls for collecting US imagery on-location and not in the lab, we prototyped a HATS-ProVoce unit that had to be:  light weight;  unitized—a system that can be broken down for transportation to remote locations—singers’ homes, studios, dressing rooms, and so forth; and  stable—maintains the spatial relationship between the subject’s head and the transducer while allowing mandible movement.

FIGURE 12. US image showing the water bolus starting from the alveolar ridge to obtain a stable position of the hard palate.

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FIGURE 13. The HATS rig built out of a professional microphone boom stand (vertical) and two Manfrotto universal photo arms. Vertical stability. Vertical stability is accomplished with the use of a robust professional microphone boom stand as the frame to which all other equipment is attached. To add additional vertical stability as well as an aid in maintaining spatial reference between the subject and the system, a special Manfrotto heavy-duty clamp solidly connects the vertical stand to a horizontal platform that is fixed to the seat bottom of the chair supporting the subject. With this support in place, we enjoy two controls on the positional accuracy of the vertical unit: the fully extended tripod legs on the floor and the horizontal connection to the chair seat.

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FIGURE 14. Detail of the HATS in action showing the transducer and the intercessory fluid reservoir that permits mandible movement during image acquisition. Also, note the reference points at the forehead and under the nose that stabilizes the skull. Standoff to permit jaw movement. After the subject’s head is stabilized in the HATS, the transducer arm is rotated into position below the chin (Figure 14). Because we are investigating the drop of the posterior mandible (LMM), we

Horizontal stability. To that vertical unit, we attach Manfrotto photography arms that have the advantage of strong construction and almost universal adjustment possibilities. These enable us to precisely tune the rig to each subject. Using these arms, we can fix the horizontal stabilizers (forehead, nose, and transducer) and maintain the spatial relationship of our subject to our equipment (Figure 11). The remaining components of the HATS equipment are:  Transducer stabilizer/holder with a universal articulated fitting so the transducer can be adjusted on all planes;  Forehead rest with an additional velcro strap to fit around the subject’s head to keep it in contact with the forehead rest;  Under-the-nose reference arm to help assure the vertical stability of the subject’s head and prevent head rotation; B Before the HATS will be used during phase II, a courseadjustment mechanism from an old microscope will be added between the transducer holder and the transducer to permit us to make very fine vertical adjustments to the transducer. This ability will be vital to obtaining the best tongue-surface imagery as the transducer must read up through the fluid reservoir.  Microphone for recording samples for acoustic analysis; and  Separate side-view video camera that records throughout the protocol, on its own tripod.

FIGURE 15. US image embedded in a sagittal profile. The posterior tongue appears on the left. Note the angular shadow on the right side of the image. This is an acoustic shadow cast by the front of the mandible that unfortunately prevents us from seeing the extreme anterior tip of the tongue. Illustration by Garyth Nair.

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FIGURE 16. Oral cavity producing a spoken /ɑ/ and /i/ vowel (left) and performing an LMM /ɑ/ and /i/ vowel (right). Notice the size and shape of the fluid reservoir at the bottom of the wedge. It indicates that the mandible has dropped approximately 1 cm. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.) Illustration by Angelika Nair. must make allowance for vertical jaw movement and still maintain acoustic contact between the surface of the transducer and the flesh on the bottom of the subject’s jaw. This continuity is accomplished through the use of a standoff (water-filled, acoustically transparent reservoir) between the transducer head and the bottom of the jaw (Figure 12). By providing a generous amount of US gel between the (1) transducer head and the reservoir and the top of the reservoir and (2) the flesh on the bottom of the subject’s jaw, acoustic continuity can be maintained so that the US signal remains viable no matter what elevation the mandible attains during the production of each phoneme under study (Figure 15).

MRI This part of the pilot study was conducted in collaboration with the Medical University of Graz, Austria, Franz Ebner, head of radiology, and Gernot Reishofer, medical physics expert, respectively. Measurements were performed on a Siemens Magnetom Tim TRIO using a 12-channel head coil combined with a four-channel neck coil. The imaging of the spoken and sung passages was performed with a temporal resolution of 0.8725 seconds, frame rate 1.15/s. The sequence parameters for the 2D turbo flash sequence were as follows: echo time (TE) 1.49 ms, repetition time (TR) 868 ms, flip angle (FA) 10 , matrix 192 3 199, field of vision (FoV) 183 3 199 m2, 8 mm slice thickness.

FIGURE 17. Three MRI images showing the LMM at rest (left), back vowel (middle), and front consonant (right). The different lines showing the SAR (turquoise), the positions of the mandible (green), and the larynx (blue) and their elevations (M, L). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

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One image at the time of each spoken and sung vowel was performed using a turbo-spin-echo sequence with the following parameters: TE 17 ms, TR 2000, FA 122 , matrix 224 3 320, FoV 220 3 220, 2 mm slice thickness. The subject was introduced to the same protocol as in the US imaging and chose a comfortable pitch for the sung tasks. Image analyses. The measurements from the US images were obtained by using the onscreen measurement tool Screen Calipers (Version 4.0). By calibrating the numbers of pixels to the integrated axial length unit of the US machine measurements for the elevation of the mandible were taken from the standoff (Figure 16). The acquired MRI imagery was displayed by means of the syngo fastView (Siemens). The software’s integrated measuring tool was used to obtain the mandible drop capacity and the laryngeal elevation. For the mandible and laryngeal drop, a protocol with the following landmarks was applied (Figure 17). A horizontal line was drawn from a posterior stable anatomical reference (SAR), right around the atlas and axis area. From there, in a 90 angle, the distance to the bottom midpoint of the mental protuberance (prominence of the chin at the anterior part of the mandible bone) was taken to measure the jaw opening and the laryngeal drop. To obtain the values of LMM from both US and MRI, measurements were taken from the spoken/sung [ɑ] and [i] vowel as well as the sung Italian phrase. The values for both the mandible and the laryngeal movement were normalized by calculating the resting mandible/larynx to the SAR (ie, D0 ¼ Rest  Rest). Subsequently, the mandible/laryngeal drop of any phoneme was subtracted from its resting position (ie, D[ɑ] ¼ Rest  max). The formula for the efficiency value (%) of the laryngeal drop derived from the mean of range of drops divided by the maximum drops (Rest  max). %Effcy ¼ mean drop=max: drop Acoustic considerations. Audio recordings of each subject were made during the US and the MRI scanning procedure. For the US, a headset microphone (Known-Brainer) was used and run through an external USB sound card (Andrea PureAudio USB) for optimal performance. Acoustical signals during the MRI scanning procedure were acquired through a commercial microphone and recorded with Windows sound recorder. Acoustical documentation was measured by means of the Pratt software (University of Amsterdam, NL) and VoceVista 3 (D. Miller). Because a normal within-subject variability can be expected in the toggle between spoken and sung [ɑ] and [i] vowel, a single repetition may not be an ideal exemplar of the task. Thus, actual measurements were taken for the second repetition and midpoint of the vowel. However, because of the loudness of the MRI noise, few viable audio samples could be used for actual measurement. RESULTS The LMM is a specialized resonance creation technique that seems to be used mostly by elite singers. It features a downward

FIGURE 18. Increase in vocal resonance during LMM. The dark herring-boned area denotes the resonance space available during a non-LMM /i/ vowel. The white areas are the spaces that are added during LMM. Image from our collaboration with the Medical University of Graz, Austria.

relaxation of the singer’s posterior mandible that can produce enormous resonance gains through enlargement of space in the oral cavity as well as concomitant resonance pharyngeal area gains because of a significant drop in laryngeal elevation (Figure 18). These gains in resonance capacity for all areas of the instrument acoustically interact and are a major component in the type of rich tone we associate with classical singing. (Phase II of this study will attempt to ascertain the prevalence of LMM in the technique of elite singers.) When skillfully used by the classical singer, LMM appears to be applied to the production of ‘‘all’’ a singer’s vowels and consonants. Figure 19 showing a spoken/sung comparison of the vowels [ɑ] and [i] from subjects 1 to 4 in the US and subjects 1 to 5 in the MRI procedure. Overall, all four subjects showed a clear employment of LMM when singing. The average of the vertical drop ranged between 0.7 and 2.09 cm. Within the sung vowels, subjects 1 and 2 showed an increased drop of the mandible on the vowel [i] versus subjects 3 and 4 who showed an increased drop on the vowel [ɑ]. Also of note is subject 3 whose spoken vowels showed an almost sung LMM use, indicating an impressionistically ‘‘sung spoken’’ vowel. With the employment of LMM an expected increase in intensity can be observed (Table 2). However, compared with the other subjects, the increased LMM on the spoken vowels of subject 3 did not show a concomitant increase in intensity but rather equal (0.5 dB) to subject 4 with less LMM. Measurements from the MRI procedure confirmed the drop of the mandible. However, in three of the four US subjects, a general increase of LMM on ‘‘all’’ tasks was observed (Figure 19, middle). In particular, the sung vowels showed double (subjects 1 and 4) to quadruple (subject 2) the increase.

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TABLE 2. Intensity Values for the Sung and Spoken Vowels From the US Procedure Intensity (dB SPL) From US Task Spoken

Singer

Vowel

Mean

Max

Min

Subject 1

[ɑ] [i] [ɑ] [i] [ɑ] [i] [ɑ] [i] [ɑ] [i] [ɑ] [i] [ɑ] [i] [ɑ] [i]

46.7 38.6 51.8 47 55.5 42.2 56 43 65.1 61 65.3 57.4 69.3 54.6 71.3 61.9

48.3 41 55 51 57.7 44.4 57.7 44.4 67.6 65.4 68.7 60.4 71.7 56.3 76.6 63.6

40 32.2 45.6 39.8 48.9 37.2 50.9 40 63.1 57.3 63.2 54.9 61.9 52.2 55.4 54.7

Subject 2 Subject 3 Subject 4 Sung

Subject 1 Subject 2 Subject 3 Subject 4

FIGURE 19. Spoken and sung LMM comparison of the vowels [ɑ] and [i] from the US procedure (top). LMM comparison of the vowels [ɑ] and [i] spoken (spk) and sung (sng) of each subject from the MRI procedure (middle). Comparison of the laryngeal elevation on the spoken (spk) and sung (sng) vowels [ɑ] and [i] from the MRI procedure (bottom; light gray and white columns alternating between subjects). Also of note is subject 3 who showed a decrease of LMM on both spoken and sung vowels. In addition, with the applied LMM, an overall enhancement of the harmonics and the Fs in particular can be observed (Figures 20 and 21). The increased LMM of subject 2 showed a substantial increase in both Fs and the first harmonics (H2 and H4 in [ɑ] and H1 in [i]). The Fs in subject 4 increased considerably and enhanced H2 and H4 in the vowel [i]. Subject 3 on the other hand had a slight enhancement of Fs, H2 in the vowel [ɑ] and H1 in the vowel [i]. Figure 22 shows the laryngeal elevation on the spoken and sung vowels. Overall, with the LMM, a concomitant laryngeal drop can be observed in all subjects. The average from the vertical drop ranged from 0.14 to 2.73 cm. However, on the

spoken and sung vowels [i], respectively, subject 3 has little mandible and even less laryngeal drop. On the sung vowel [i], subject 2 showed a 29.6-mm mandible versus a 9.7-mm laryngeal drop. Also of note is subject 4 who showed more laryngeal than mandible drop on the spoken vowel [ɑ] and sung vowel [i] as well as equal drop on the sung vowel [ɑ] of both the larynx and mandible. Subject 5 on the other hand showed little laryngeal drop on the spoken vowels and the sung vowel [ɑ] but more on the sung vowel [i] than the mandible drop. A major difference in the efficiency of LMM on a sung Italian phrase can be observed between US and MRI (Figure 22). Subjects 3 and 4 in particular showed a 40% higher efficiency, whereas the LMM efficiency of subject 1 was almost identical (+2% in MRI). In the laryngeal elevation, subject 1 showed the highest laryngeal elevation with 92.3% followed by subject 4 with 86.9%, subject 5 with 84.2%, subject 3 with 63.9%, and subject 2 with 46.7%. DISCUSSION The primary goal of this pilot study was to show that the LMM is a resonance creating technique used by classical singers and its anatomical and ‘‘physiological’’ effects on the surrounding structures. Because only five subjects were examined, no statistical analyses can be made. The use of US allowed for real-time videos of the singers in action on individual phoneme production and phoneme-to-phoneme transitions during the LMM. The reason for the use of MRI and US was to correlate both imaging modes, double check the US interpretation accuracy, and to study ancillary structures not visible in the US (ie, TMJ/ condyle environment, laryngeal elevation, etc). On the images shown from our study, one can easily see the substantial difference in the actual tongue shape and position

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FIGURE 20. Graphics from the US procedure of the mean amplitude (dB) of the fundamental frequency (F0), the harmonics in the range of the first formant (F1) for [ɑ] and [i], as well as in the range of 2.0–3.5 kHz. Various pitches and multiples of the fundamental frequency (nF0) are indicated in the horizontal axis of each graph. Note, because of illness, subject 5 could not participate in this imaging procedure and is not included in this illustration.

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FIGURE 21. Graphics from the MRI procedure of the mean amplitude (dB) of the fundamental frequency (F0), the harmonics in the range of the first formant (F1) for [ɑ] and [i], as well as in the range of 2.0–3.5 kHz. Various pitches and multiples of the fundamental frequency (nF0) are indicated in the horizontal axis of each graph. Note, the audio of subject 1 was not usable and could not be included in this illustration. for the vowels. Both modes of imagery showed that LMM was used while singing, with the concomitant lowering of the larynx and elongating the pharynx thus ultimately forcing the tongue to be far more active than in speech. The floor of the tongue

sits much lower in the oral cavity. Hence, the tongue must work more intensely on the vertical plane to achieve the Point of Articulation necessary for all phonemes (Figure 23). However, this also means that the airspaces surrounding the tongue

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The LMM and Its Resonential Implications for Elite Singers

FIGURE 22. Overall efficiency of LMM from US (top), MRI (middle), and the laryngeal elevation (bottom) on an Italian sung phrase. Note, because of illness, subject 5 is missing in the US. will produce far more resonance. Concomitant to the increase of the LMM, measurements of the energy increase confirmed a considerable enhancement of all harmonics and the Fs, respectively (subjects 2 and 4 in particular). However, in three of the four subjects, we observed a significant increase of LMM in the MRI procedure. Possibly, this increase was associated with the standoff (water reservoir) in the US that allows jaw movement but still maintains acoustic contact between the surface of the transducer and the flesh on the bottom of the subject’s jaw. Hence, the singer is feeling a slight resistance to the jaw and may subconsciously refrain from relaxing the mandible to the maximum. Solutions for the future may be a ‘‘training session’’ in which the singer can get more acquainted with the sensation of the standoff and its enlargement to the point before it loses acoustic continuity so the mandible has even more room for movement. Also, two of the four MRI subjects showed a double increase of the mandible drop. However, a conclusion to double the measurements taken from the US would need many more subjects to

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be validated. On the other hand, subject 3 showed a decrease of LMM in the MRI. Because we observed it in both spoken and sung vowels, a contrary speculation could be made that for this singer, the standoff may have stimulated a more conscious mandible movement, thus feeling the need for a more prominent mandible drop. This may be echoed by the acoustical measurements. A more active mandible elevation of subject 3 could be observed although it did not seem to translate into the acoustic outcome like in the other subjects. The enhancement of the harmonics and the Fs, respectively showed a minimal increase although the applied LMM was less in the MRI than in the US. Perhaps, this may be correlated to the interaction of mandible and larynx. It could be speculated that the employment of the LMM in subject 3 was rather more forceful than naturally relaxed, hence not allowing for a concomitant drop of the larynx and ultimately preventing an acoustic energy increase. Also, we observed a correlation between the laryngeal elevation and the LMM though not proportionate to the mandible drop. Subject 4 showed more laryngeal drop on the spoken vowel [ɑ] and sung vowel [i]. We believe this may be a probable consequence of the complex interaction of the head and neck muscles. In the case of subject 4, dropping the mandible with a more pronounced relaxation of the masseter and an even greater relaxation of the suprahyoids (joining the mandible to the hyoid bone) and the infrahyoids (joining the hyoid bone to the sternum and clavicle) created a seemingly posterior angle of the mandible (Figure 24). Because the stability of the joint is maintained by constant activity of the muscles that pull across the joint, primarily the elevator, even in the resting state, these muscles are in a mild state of contraction. However, when the mouth opens, a controlled relaxation and lengthening in the masseter can be observed. In addition, when the muscle groups controlling the elevation of the larynx and hyoid bone are relaxed, like taking a breath, this will lower the larynx. Thus, with the measurements taken from the prominence of the chin at the anterior part of the mandible bone, the actual drop of the larynx seems to be correlated but in a nonproportional unit. Additional aspects that could possibly be influential factors are the overall posture and the cervical spine. Sataloff24 points out that the extrinsic muscles are critical in maintaining a stable laryngeal skeleton that permits effective movement of the delicate intrinsic musculature. With the finely tuned balance of head and neck muscles, hyperextension will certainly influence the movement of the larynx and make it difficult to relax. A critical question in classical singing resonance is the consistency of this maneuver, phoneme-to-phoneme. Although this will be a subject for another article, for the sake of completeness, a few facets shall be included in this discussion. Unless the singer has worked to perform all phonemes—not just vowels—in the optimal acoustic environment of the LMM, his or her sound will lack consistency (Figure 25). For this reason, we have measured the efficiency of LMM while singing an Italian phrase and observed major differences in three of the four subjects between US and MRI. Especially, subjects 3 and 4 showed a 40% higher efficiency which could be attributed to the previously mentioned standoff resistance in the US procedure.

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FIGURE 23. Oral cavity producing a spoken /ɑ/ and /i/ vowel (left) and performing an LMM /ɑ/ and /i/ vowel (right). Notice the size and shape of the fluid reservoir at the bottom of the wedge (green) as well as the advanced tongue root on the sung /i/ (circled and indicated by an arrow). The latter indicating an increase in pharyngeal volume. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.) Illustration by Angelika Nair.

However, comparing the LMM and laryngeal drop efficiency in the MRI, we observed (in that order) that subjects 1, 4, and 5 maintained the highest laryngeal elevation while using an LMM strategy with an entire jaw drop (Figure 26C) such as subjects 1 and 5, and a posterior drop of the mandible (Figure 26D) such as subject 4. For subject 2, however, the LMM only reflects in a 47% laryngeal drop and subject 3, 63.9%. Unfortunately, with the loudness of the MRI noise, an acoustical analyses of the entire phrase were not possible. However, some extracts show similar harmonic enhancement as in the sung vowels. To summarize the results, we found that all five subjects: (1) utilized the LMM with greater or lesser success; (2) exhibited the mandible strategies shown in Figure 26; and (3) radiated signal correlated with the results shown in the imagery. Also, there is visual and aural evidence available for the existence of the LMM: (4) far higher percentage of mouth opening during sung passages; (5) visible evidence of a lowered posterior mandible (the angle of the ramus); (6) where visible, the laryngeal prominence (the protruding Adam’s apple) reveals a consistently low larynx; and (7) less visible evidence of superficial tension in the lower neck region.

But, let us have a look at the internationally ranked singer Thomas Hampson singing a single ‘‘la’’ from Rossini’s ‘‘Largo al factotum’’ (Figure 27). In these two images, one can clearly see that the entire jaw platform is down and that the tongue is doing all the work of the language. This use of the LMM engenders optimal resonance in the posterior oral cavity and allows the shift from /l/ to /ɑ/ with a minimum of movement and a consistently large resonance space. The resulting sound is a Hampson hallmark and is one of the factors that place him in the highest rank of today’s singers. CONCLUSIONS The images from both US and MRI show that the LMM is a technique used in classical singing. The strategies of the LMM varied between the entire drop of the jaw platform and the posterior drop of the mandible, but both resulted in a concomitant drop of the larynx. However, the enhancement of the first harmonics and the Fs as well as the increase of the intensity was greater with the drop of the entire mandible. Clear modifications in the tongue shape for all phonemes were observed when the LMM was used to maintain the integrity of the phoneme while increasing the sound output. In a column of the Journal of Singing, Titze25 addressed the question why classical singers widen their airways in the pharynx and the back of the oral cavity. Acoustically, the answer is that a large mouth opening is needed to radiate lots of sound to the listener—such as brass and woodwinds instrument that have a bell to get more acoustic power into free space. However, an

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FIGURE 24. Top right image, spoken /i/ and the left image, sung /i/ with full classical resonance. Note the drop of the mandible and the larynx. Note that, in the top right-hand static image, the singer’s velopharyngeal port was not closed—in a moving MRI, the port would have been closed and would appear identical to the corollary region in the top left side image. Bottom images showing spoken /ɑ/ (right) and sung /ɑ/ (left) with full classical resonance. Also note the different angles following the LMM (yellow line). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.) Images from our collaboration with the Medical University of Graz, Austria.

inverted megaphone mouth shape is also needed to produce the mixed registration with vowel modification. Hence, there is a need to expand the throat. The comparison of US and MRI imagery showed similar outcomes in shape and direction of the tongue and mandible although the drop of the mandible measured in the US does not represent the actual drop. However, the deformation of the standoff does show clear directions as well as the angle of the mandible drop. Also, with a frame rate of 30 fps, more tongue shapes of all phonemes can be observed. We are already working to quantify the useful factors of the biodynamic system for use in the voice studio. With the use of US imagery in the voice studio (supported by MRI), the authors of this study have already experienced a rapid acceleration in their students’ understanding of these complex vocal strategies. However, with the acquisition of a portable US machine (GE Logiq E) and its use in the voice studio, we are seeing even greater benefits to all classical singers in training:  biofeedback for phoneme rehabituation (overcoming the problem of relative lack of tongue proprioceptors,

thereby allowing the singer to sense the precise position of the tongue and how it is shaped); The front portion of the tongue has many proprioceptors (those nerves that give the brain ‘‘the awareness, often subconsciously, of weight, posture, movement, position in space in relationship to the body; based on sensory input from nerve terminals in joints and muscles . ’’.26 However, as we progress back along the tongue body, the density of proprioceptors drops precipitously. Thus, the singer has a difficult time sensing where the tongue is and how it is shaped.  Faster correction of a singer’s phonemic problems;  Teaching the LMM; and  Redefining vowel shapes as well as consonants resonance. Most classical singers in training unconsciously attempt to use LMM in their vowels as a way of attempting to duplicate the classical vowel tone they hear around them. However, within these vowel attempts, one rarely encounters singers or pedagogues discussing the resonance requirements of ‘‘consonants.’’ It is hoped that the collection of such imagery might

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 a better understanding of the previous verbally described area and/or task;  the images and shapes of the tongue did not match what they had envisioned themselves;  better control of the tongue because of the visual feedback; and  sensitization to one’s resonance creation, particularly pharyngeal.

FIGURE 25. Comparison of spoken (left) and sung (right) consonants. Note again the size and shape of the fluid reservoir on the bottom wedge. EdgeTrak software capturing the edge of the sagittal tongue profile (red line) as well as the hard palate (yellow line). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

add to our scientific knowledge of the physioacoustics of upperlevel resonance creation and ultimately lead to the creation of a resource that may enlighten pedagogical approaches for all singers, not just those of the highest rank. A new book The Secret Life of Consonants: why don’t my songs sound as good as my warm-ups? is already in the making by Angelika Nair, using the US and MRI material and results acquired from this research project. Some of the preliminary remarks from the students themselves are:

Similar eye-body biofeedback is already in use in the form of virtual real-time spectrography. This technology is now in extensive use in many voice studios worldwide, including ours at Drew University and the College of St. Elizabeth. Students’ progress is greatly accelerated once we present them with a graphic of the acoustics of their singing. This innovative pedagogical aid and the practical integration of new knowledge into musical training were pioneered by Prof. Garyth Nair in his book, Voice—Tradition and Technology.27 As with any new imagery, some guidance is necessary to be able to read the US imagery. However, the authors already integrated the US in their own voice studio and use it in workshops and master classes. We have found that after a few minutes of introduction, the student very quickly familiarizes him/herself with the tongue contour and starts to learn to control its movement. It would be financially unreasonable to expect voice pedagogues to buy their own portable US machine. The solution to this problem lies in the development of USB US transducers which can be used directly with any Windows computer (laptop, tablet, or desktop). Unfortunately, the current state of USB transducers does not meet the specifications necessary, especially for sounds such as stops, clicks, and flaps. To obtain all the sounds, one needs a minimum of 30 fps; and USB transducers at the moment only reach a maximum of 15 fps (though enough for just vowels). It is the authors’ hope that, with the development of USB probes, this will change and find its way into the voice studio, similar to the virtual real-time spectrography. Beside the different types of equipment we are currently working with (portable US, laptop, converter, cables, etc), we also

FIGURE 26. Different mandible strategies found in all five subjects. (A) mandible at rest. (B) Anterior drop of the mandible (speech template). (C) Complete LMM, entire jaw platform is down. (D) Posterior drop of the mandible.

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FIGURE 27. The internationally ranked singer, Thomas Hampson, in two frames from a video of him singing the word ‘‘la’’ from Rossini’s Largo al factotum. The two images are just 1/30000 of a second apart in time. On the left, one sees the /l/, and on the right, the open /ɑ/. The two guidelines indicate the elevation of the posterior and anterior mandible. have to combine both sets of images on the screen by capturing the US video on the laptop through the Debut Video Capture software in one Window and running the spectrogram (Gram Lite, VoicePrint) software in another Window. The vision for the future with the USB transducer would be to combine the US with the real-time spectrum analyses within one software, similar to VoceVista which displays the signals in combination of spectrogram, power spectrum, and high time-resolution waveforms. We hope to have the interest of Donald G. Miller to consider the ability to include US real-time imagery in VoceVista (Figure 28). Additionally, in a recently started collaboration with the Interdisciplinary Speech Research Laboratory (ISRL) at University of Columbia, Vancouver (research project: The Efficacy of Ultrasound in the Voice Studio), we have also presented our vision to the Electrical and Computer Engineering (ECE). The ISRL and ECE developed ArtiSynth (www.artisynth.org), a state-of-the-art biomechanical simulation platform focused on modeling the human vocal tract. It is our hope for the future that this 3D mechanical modeling system may be developing into a real-time computer animation, showing the US signal of the tongue in 3D. All these developments may take us toward removing facets of vocal technique from the realm of opinion and into a more objective understanding of how the instrument works. Given the non–fact-based technique that we routinely encounter in singers—training that cannot be understood in terms of anatomy or physics—we need more voice science that can clarify how the instrument actually works and that can help move pedagogy more toward the objective side (a movement, that has already begun in the best voice teaching centers).

It is a very short leap from the use of US as feedback in the voice studio to its use by the speech-language pathologist to help those with speech defects correct them faster. Thus, the gains for such use of US are not limited to research but may have a broader application big enough to constitute a new market for US used in this way. Voice science has not pointed out any new techniques during the past 30+ years, but it has shown the efficacy of certain technical approaches and helped to illuminate and eliminate unhealthy vocal practices. There are areas of the voice yet to be studied just like this study of the LMM, that will benefit all singers and teachers of singing into the future.

FIGURE 28. Authors vision of US through a USB transducer, incorporated in VoceVista and run on a tablet. Illustration by Angelika Nair.

20 Acknowledgments The authors would like to acknowledge Dr. Maureen Stone for her generous contributions in her consultations and lab equipment; Dr. Wolfgang Klinger (Neurologist) for making his practice with its GE Logiq 7 ultrasound machine available to us; and Univ. Prof., Dr. med., Dr. phil., Franz Ebner (clinical expertise) and team of the Medical University of Graz, Austria for providing us >150 MRI scans. Last but not least, the authors also thank Anne Jacobson for improving my English.

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