5pAOa7 – Estimating muddy seabed properties using ambient noise coherence

David R. Barclay1– dbarclay@dal.ca
Dieter A. Bevans2 – dbevans@ucsd.edu
Michael J. Buckingham2 – mbuckingham@ucsd.edu

  1. Department of Oceanography, Dalhousie University, 1355 Oxford St, Halifax, Nova Scotia, B3H 4R2, CANADA
  2. Marine Physical Lab, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, #0238, La Jolla CA, 92093-0238

Popular version of paper 5pAOa7: “Estimating muddy seabed properties using ambient noise coherence”
Presented Friday afternoon, November 9th, 2018, 3:00 – 3:15PM, Esquimalt Room 176th ASA Meeting, Victoria, B.C.

Figure 1. The autonomous Deep Sound acoustic recorder on the rear deck of the R/V Neil Armstrong

The ocean is a natural acoustic waveguide, bounded by the sea surface and seabed, inside which sound can travel large distances. In the frequency range of 10’s – 1000’s of Hertz, seawater is nearly transparent to sound, absorbing only a small fraction of energy of the acoustic wave as it propagates in the ocean. However, sound transmitted in this shallow water ocean waveguide reflects off the bottom, losing some energy which is either transmitted into the bottom, or absorbed by the sediment. In order to predict and model the distances over which any acoustic ocean monitoring, detection, or communication systems may operate, accurate knowledge of the acoustic properties (the sound speed, attenuation, and density) of the seabed must be known.

The majority of the ocean’s bottom has a top layer of sand or gravel, where the grain sizes are large enough that gravity and friction dictate the micro-physics at inter-granular contacts and play a large roll in determining the sound speed and attenuation in the material. In silts and clays (a.k.a. muds), grain sizes are on the order of microns or less, so electrochemical forces become the dominant factor responsible for the mechanics of the medium. Mud particles are usually elongated, with high length-to-width ratios, and when consolidated they form stacks of parallel grains and ‘card-house’ structures, giving the ensemble mechanical and acoustical properties unlike larger grained sands.

In March and April 2017, as part of the ONR-supported Seabed Characterization Experiment (SCE) designed to investigate the geo-acoustic properties of fine-grained sediments, a bottom lander known as Deep Sound was deployed on the New England Mud Patch (NEMP) from the R/V Neil Armstrong. The NEMP occupies an area of approximately 13,000 km2 off the east coast of the USA, 95 km south of Martha’s Vineyard, and is 170 km wide, descending 75 km across the continental shelf with an unusually smooth bathymetry. The region is characterized by a layer of mud, accumulated over the last 10,000 years, estimated to be as thick as 13 meters [1].

seabed

Figure 2. Location of the five Deep Sound deployments, plotted over the two-way travel time, a proxy for mud layer thickness (where 16 milliseconds is equivalent to 13 meters)

Drop #1

Drop #2

Drop #3

Drop #4

Drop #5

Two way travel time [ms]

The American naturalist Louis François de Pourtalès first described this ocean feature in 1872 [2], in the context of a convenient navigation aid for whaling ships headed into Nantucket and New Bedford. Sailors would make depth soundings using a lead weight with a plug of wax on the bottom which collected a small sample of the seabed. Since the mud bottom was unique along the New England seaboard, ships were able to determine their location in relation to their home ports in foggy weather.

Deep Sound (Fig. 1) is a free-falling (untethered), four channel acoustic recorder designed to descend from the ocean’s surface to a pre-assigned depth, or until pre-assigned conditions are met, at which point it drops an iron weight and returns to the surface under its own buoyancy with a speed of ~0.5 m/s in either direction. In this case, the instrument was configured to land on the seabed, with the hydrophones arranged in an inverted ‘T’ shape, and continue recording until either a timer expired, or a battery charge threshold was crossed. Almost 30 hours of ambient noise data were collected at five locations on the NEMP, shown in Fig. 2.

From the vertical coherence of the ambient noise, information about the geo-acoustic properties of the seabed was extracted by fitting the data to a model of ocean noise, based on an infinite sheet of sources, representing the bubbles generated by breaking ocean surface waves. The inversion returned estimates of five geo-acoustic properties of the bottom: the sound speed and attenuation, the shear-wave speed and attenuation, and the density of the muddy seabed.

 

  1. Bothner, M. H., Spiker, E. C., Johnson, P. P., Rendigs, R. R., Aruscavage, P. J. (1981). Geochemical evidence for modern sediment accumulation on the continental shelf off southern New England. Journal of Sedimentary Research, 51(1), pp. 281-292.
  2. Pourtales, L.F., (1872). The characteristics of the Atlantic sea bottom off the coast of the United States: Report, Superintendent U.S. Coast Survey for 1869, Appendix 11, pp. 220-225.
  3. Carbone, N. M., Deane, G. B., Buckingham, M. J., (1998). Estimating the compressional and shear wave speeds of a shallow water seabed from the vertical coherence of ambient noise in the water column. The Journal of the Acoustical Society of America, 103(2), pp. 801-813.

2pBAa1 – New way to treat kidney stone sufferers

Michael Bailey – mbailey@uw.edu
Center for Industrial and Medical Ultrasound
Applied Physics Laboratory
University of Washington
1013 NE 40th St.
Seattle, WA 98105, USA
apl.uw.edu/pushingstones

Popular version of paper 2pBAa1
Presented Tuesday afternoon 1:00 pm, November 6, 2018
176th ASA Meeting, Victoria BC

We are trying to change the way kidney stones are managed. Our solution is a painless, one-hour session where stones are identified, broken, and expelled from the kidney to pass naturally. This is an update on current progress to the doorstep of FDA clearance of an expelling system and first in human trials of a stone breaking system.

Stones are common and are currently managed in a long, costly, painful process. One in 11 Americans will have stones and cost of disease is $10B annually in the U.S. Stones are painful when they obstruct urine flow out of the kidney. Most people go to the Emergency Department where they to sent to a radiology department for a CT exam and then are given pain medication. They are expected to pass the stone within 3 weeks. If pain cannot be managed a surgery is performed to allow urine out of the kidney but not to remove the stone. If the first surgery has been performed, the stone is too large to pass or does not pass, or symptoms cannot be controlled, the patient has surgery to break the stone or stones usually with the expectation of the patient passing the fragments naturally. About one-third of surgeries leave fragments that can grow to again be symptomatic stones. Recurrence requiring intervention is about 50% within 5 years. Patients after the second stone event are usually monitored by CT annually for new stones. This process subjects patients to pain, anxiety, and ionizing radiation over a long time.

Our talk presents an update on our new non-invasive stone removal technology.  We will present progress and results of several parallel clinical trials.  Our NASA-funded study is to reposition an obstructing stone in the Emergency Department to relieve pain. One NIH-funded study is a randomized clinical trial to measure long term benefit of expelling fragments that remain after surgery. The status and design of studies to test the complete imaging, breaking and expelling technology will also be discussed. So far over 50 subjects are participating in the clinical trials.

We also will mention plans to improve the technology and further expand its use. This includes outputs to break stone faster based on image guided feedback of the progression of the individual’s specific procedure and stone characteristics. It also includes tractor beam technology to grab and steer stones and fragments through the complex three-dimensional path out of the kidney. Other talks in the session provide more detail on the development of these additional technologies.

Figure 1 shows a movie taken from a camera inside a patient’s kidney while the ultrasound sent from a probe on the patient’s skin causes an 4-mm (1/4 inch) kidney stone to move out of the kidney.

Figure 2 is a drawing of the new system and process.

1pSA8 – Thermoacoustics of solids – Can heat generate sound in solids?

Haitian Hao – haoh@purdue.edu
Mech. Eng., Purdue Univ.
Herrick Labs,
177 S. Russell St.
Rm.1007
West Lafayette, IN 47906

Carlo Scalo
Mech. Eng., Purdue Univ.
Herrick Labs,
177 S. Russell St.
Rm.1007
West Lafayette, IN 47906

Mihir Sen
Aerosp. and Mech. Eng.
Univ. of Notre Dame,
Notre Dame, IN

Fabio Semperlotti
Mech. Eng.
Purdue Univ.
West Lafayette, IN

Popular version of 1pSA8, “Thermoacoustic instability in solid media”
Presented Monday, May 07, 2018, 2:45pm – 3:00 PM, Greenway C
175th ASA Meeting, Minneapolis
Click here to read the abstract

Many centuries ago glass blowers observed that sound could be generated when blowing through a hot bulb from the cold end of a narrow tube. This phenomenon is a result of thermoacoustic oscillations: a pressure wave propagating in a compressible fluid (e.g. air) can sustain or amplify itself when being provided heat. To date, thermoacoustic engines and refrigerators have had remarkable impacts on many industrial applications.

After many centuries of thermoacoustic science in fluids, it seems natural to wonder if such a mechanism could also exist in solids. Is it reasonable to conceive thermoacoustics of solids? Can a metal bar start vibrating when provided heat?

The study of the effects of heat on the dynamics of solids has a long and distinguished history. The theory of thermoelasticity, which explains the mutual interaction between elastic and thermal waves, has been an active field of research since the 1950s. However, the classical theory of thermoelasticity does not address instability phenomena that can arise when considering the motion of a solid in the presence of a thermal gradient. In an analogous way to fluids, a solid element contracts when it cools down and expands when it is heated up. If the solid contracts less when cooled and expands more when heated, the resulting motion will grow with time. In other terms, self-sustained vibratory response of a solid could be achieved due to the application of heat. Such a phenomenon would represent the exact counterpart in solids of the well-known thermoacoustic effect in fluids.

By using theoretical models and numerical simulations, our study indicates that a small mechanical perturbation in a thin metal rod can give rise to sustained vibrations if a small segment of the rod is subject to a controlled temperature gradient. The existence of this physical phenomenon in solids is quite remarkable, so one might ask why it was not observed before despite the science of thermoacoustics have been known for centuries.

solid-state thermoacoustic device

“Figure 1. The sketch of the solid-state thermoacoustic device and the plot of the self-amplifying vibratory response.”

It appears that, under the same conditions of mechanical excitation and temperature, a solid tends to be more “stable” than a fluid. The combination of smaller pressure oscillations and higher dissipative effects (due to structural damping) in solids tends to suppress the dynamic instability that is at the origin of the thermoacoustic response. Our study shows that, with a proper design of the thermoacoustic device, these adverse conditions can be overcome and a self-sustained response can be obtained. The interface conditions are also more complicated to achieve in a solid device and dictates a more elaborate design.

Nonetheless, this study shows clear theoretical evidence of the existence of the thermoacoustic oscillations in solids and suggests that applications of solid-state engines and refrigerators could be in reach within the next few years.

4pMU4 – How Well Can a Human Mimic the Sound of a Trumpet?

Ingo R. Titze – ingo.titze@utah.edu

University of Utah
201 Presidents Cir
Salt Lake City, UT

Popular version of paper 4pMU4 “How well can a human mimic the sound of a trumpet?”
Presented Thursday May 26, 2:00 pm, Solitude room
171st ASA Meeting Salt Lake City

Man-made musical instruments are sometimes designed or played to mimic the human voice, and likewise vocalists try to mimic the sounds of man-made instruments.  If flutes and strings accompany a singer, a “brassy” voice is likely to produce mismatches in timbre (tone color or sound quality).  Likewise, a “fluty” voice may not be ideal for a brass accompaniment.  Thus, singers are looking for ways to color their voice with variable timbre.

Acoustically, brass instruments are close cousins of the human voice.  It was discovered prehistorically that sending sound over long distances (to locate, be located, or warn of danger) is made easier when a vibrating sound source is connected to a horn.  It is not known which came first – blowing hollow animal horns or sea shells with pursed and vibrating lips, or cupping the hands to extend the airway for vocalization. In both cases, however, airflow-induced vibration of soft tissue (vocal folds or lips) is enhanced by a tube that resonates the frequencies and radiates them (sends them out) to the listener.

Around 1840, theatrical singing by males went through a revolution.  Men wanted to portray more masculinity and raw emotion with vocal timbre. “Do di Petto”, which is Italien for “C  in chest voice” was introduced by operatic tenor Gilbert Duprez in 1837, which soon became a phenomenon.  A heroic voice in opera took on more of a brass-like quality than a flute-like quality.  Similarly, in the early to mid- twentieth century (1920-1950), female singers were driven by the desire to sing with a richer timbre, one that matched brass and percussion instruments rather than strings or flutes.  Ethel Merman became an icon in this revolution. This led to the theatre belt sound produced by females today, which has much in common with a trumpet sound.

Titze_Fig1_Merman

Fig 1. Mouth opening to head-size ratio for Ethel Merman and corresponding frequency spectrum for the sound “aw” with a fundamental frequency fo (pitch) at 547 Hz and a second harmonic frequency 2 fo at 1094 Hz.

The length of an uncoiled trumpet horn is about 2 meters (including the full length of the valves), whereas the length of a human airway above the glottis (the space between the vocal cords) is only about 17 cm (Fig. 2). The vibrating lips and the vibrating vocal cords can produce similar pitch ranges, but the resonators have vastly different natural frequencies due to the more than 10:1 ratio in airway length.  So, we ask, how can the voice produce a brass-like timbre in a “call” or “belt”?

One structural similarity between the human instrument and the brass instrument is the shape of the airway directly above the glottis, a short and narrow tube formed by the epiglottis.  It corresponds to the mouthpiece of brass instruments.  This mouthpiece plays a major role in shaping the sound quality.  A second structural similarity is created when a singer uses a wide mouth opening, simulating the bell of the trumpet.  With these two structural similarities, the spectrum of tones produced by the two instruments can be quite similar, despite the huge difference in the overall length of the instrument.

Titze_Fig2_airway_ trumpet

Fig 2. Human airway and trumpet (not drawn to scale).

Acoustically, the call or belt-like quality is achieved by strengthening the second harmonic frequency 2fo  in relation to the fundamental frequency fo.  In the human instrument, this can be done by choosing a bright vowel like /ᴂ/ that puts an airway resonance near the second harmonic.  The fundamental frequency will then have significantly less energy than the second harmonic.

Why does that resonance adjustment produce a brass-like timbre?  To understand this, we first recognize that, in brass-instrument playing, the tones produced by the lips are entrained (synchronized) to the resonance frequencies of the tube.  Thus, the tones heard from the trumpet are the resonance tones. These resonance tones form a harmonic series, but the fundamental tone in this series is missing.  It is known as the pedal tone.  Thus, by design, the trumpet has a strong second harmonic frequency with a missing fundamental frequency.

Perceptually, an imaginary fundamental frequency may be produced by our auditory system when a series of higher harmonics (equally spaced overtones) is heard.  Thus, the fundamental (pedal tone) may be perceptually present to some degree, but the highly dominant second harmonic determines the note that is played.

In belting and loud calling, the fundamental is not eliminated, but suppressed relative to the second harmonic.  The timbre of belt is related to the timbre of a trumpet due to this lack of energy in the fundamental frequency.  There is a limit, however, in how high the pitch can be raised with this timbre.  As pitch goes up, the first resonance of the airway has to be raised higher and higher to maintain the strong second harmonic.  This requires ever more mouth opening, literally creating a trumpet bell (Fig. 3).

Titze_Fig3_Menzel

Fig 3. Mouth opening to head-size ratio for Idina Menzel and corresponding frequency spectrum for a belt sound with a fundamental frequency (pitch) at 545 Hz.

Note the strong second harmonic frequency 2fo in the spectrum of frequencies produced by Idina Menzel, a current musical theatre singer.

One final comment about the perceived pitch of a belt sound is in order.  Pitch perception is not only related to the fundamental frequency, but the entire spectrum of frequencies.  The strong second harmonic influences pitch perception. The belt timbre on a D5 (587 Hz) results in a higher pitch perception for most people than a classical soprano sound on the same note. This adds to the excitement of the sound.

1pSC26 – Acoustics and Perception of Charisma in Bilingual English-Spanish

Rosario Signorello – rsignorello@ucla.edu
Department of Head and Neck Surgery
31-20 Rehab Center,
Los Angeles, CA 90095-1794
Phone: +1 (323) 703-9549

Popular version of paper 1pSC26 “Acoustics and Perception of Charisma in Bilingual English-Spanish 2016 United States Presidential Election Candidates”
Presented at the 171st Meeting on Monday May 23, 1:00 pm – 5:00 pm, Salon F, Salt Lake Marriott Downtown at City Creek Hotel, Salt Lake City, Utah,

Charisma is the set of leadership characteristics, such as vision, emotions, and dominance used by leaders to share beliefs, persuade listeners and achieve goals. Politicians use voice to convey charisma and appeal to voters to gain social positions of power. “Charismatic voice” refers to the ensemble of vocal acoustic patterns used by speakers to convey personality traits and arouse specific emotional states in listeners. The ability to manipulate charismatic voice results from speakers’ universal and learned strategies to use specific vocal parameters (such as vocal pitch, loudness, phonation types, pauses, pitch contours, etc.) to convey their biological features and their social image (see Ohala, 1994; Signorello, 2014a, 2014b; Puts et al., 2006). Listeners’ perception of the physical, psychological and social characteristics of the leader is influenced by universal ways to emotionally respond to vocalizations (see Ohala, 1994; Signorello, 2014a, 2014b) combined with specific, culturally-mediated, habits to manifest emotional response in public (Matsumoto, 1990; Signorello, 2014a).

Politicians manipulate vocal acoustic patterns (adapting them to the culture, language, social status, educational background and the gender of the voters) to convey specific types of leadership fulfilling everyone’s expectation of what charisma is. But what happen to leaders’ voice when they use different languages to address voters? This study investigates speeches of bilingual politicians to find out the vocal acoustic differences of leaders speaking in different languages. It also investigates how the acoustical differences in different languages can influence listeners’ perception of type of leadership and the emotional state aroused by leaders’ voices.

We selected vocal samples from two bilingual America-English/American-Spanish politicians that participated to the 2016 United States presidential primaries: Jeb Bush and Marco Rubio. We chose words with similar vocal characteristics in terms of average vocal pitch, vocal pitch range, and loudness range. We asked listeners to rate the type of charismatic leadership perceived and to assess the emotional states aroused by those voices. We finally asked participants how the different vocal patterns would affect their voting preference.

Preliminary statistical analyses show that English words like “terrorism” (voice sample 1) and “security” (voice sample 2), characterized by mid vocal pitch frequencies, wide vocal pitch ranges, and wide loudness ranges, convey an intimidating, arrogant, selfish, aggressive, witty, overbearing, lazy, dishonest, and dull type of charismatic leadership. Listeners from different language and cultural backgrounds also reported these vocal stimuli triggered emotional states like contempt, annoyance, discomfort, irritation, anxiety, anger, boredom, disappointment, and disgust. The listeners who were interviewed considered themselves politically liberal and they responded that they would probably vote for a politician with the vocal characteristics listed above.

Speaker Jeb Bush. Mid vocal pitch frequencies (126 Hz), wide vocal pitch ranges (97 Hz), and wide loudness ranges (35 dB)

Speaker Marco Rubio. Mid vocal pitch frequencies 178 Hz), wide vocal pitch ranges (127 Hz), and wide loudness ranges (30 dB)

Results also show that Spanish words like “terrorismo” (voice sample 3) and “ilegal” (voice sample 4) characterized by an average of mid-low vocal pitch frequencies, mid vocal pitch ranges, and narrow loudness ranges convey a personable, relatable, kind, caring, humble, enthusiastic, witty, stubborn, extroverted, understanding, but also weak and insecure type of charismatic. Listeners from different language and cultural backgrounds also reported these vocal stimuli triggered emotional states like happiness, amusement, relief, and enjoyment. The listeners who were interviewed considered themselves politically liberal and they responded that they would probably vote for a politician with the vocal characteristics listed above.  

Speaker Jeb Bush. Mid-low vocal pitch frequencies (95 Hz), mid vocal pitch ranges (40 Hz), and narrow loudness ranges (17 dB) 

Speaker Marco Rubio. Mid vocal pitch frequencies 146 Hz), wide vocal pitch ranges (75 Hz), and wide loudness ranges (25 dB)

Voice is a very dynamic non-verbal behavior used by politicians to persuade the audience and manipulate voting preference. The results of this study show how acoustic differences in voice convey different types of leadership and arouse differently the emotional states of the listeners. The voice samples studied show how speakers Jeb Bush and Marco Rubio adapt their vocal delivery to audiences of different backgrounds. The two politicians voluntary manipulate their voice parameters while speaking in order to appear as they were endowed of different leadership qualities. The vocal pattern used in English conveys the threatening and dark side of their charisma, inducing the arousal of negative emotions, which triggers a positive voting preference in listeners. The vocal pattern used in English conveys the charming and caring side of their charisma, inducing the arousal of positive emotions, which triggers a negative voting preference in listeners.

The manipulation of voice arouses emotional states that will induce voters to consider a certain type of leadership as more appealing. Experiencing emotions help voters to assess the effectiveness of a political leader. If the emotional arousing matches with voters’ expectation of how a charismatic leader should make them feel then voters would help the charismatic speaker to became their leader.

References
Signorello, R. (2014a). Rosario Signorello (2014). La Voix Charismatique : Aspects Psychologiques et Caractéristiques Acoustiques. PhD Thesis. Université de Grenoble, Grenoble, France and Università degli Studi Roma Tre, Rome, Italy.

Signorello, R. (2014b). The biological function of fundamental frequency in leaders’ charismatic voices. The Journal of the Acoustical Society of America 136 (4), 2295-2295.

Ohala, J. (1984). An ethological perspective on common cross-language utilization of F0 of voice. Phonetica, 41(1):1–16.

Puts, D. A., Hodges, C. R., Cárdenas, R. A. et Gaulin, S. J. C. (2007). Men’s voices as dominance signals : vocal fundamental and formant frequencies influence dominance attributions among men. Evolution and Human Behavior, 28(5):340–344.