Throat microphone

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Oxygen mask KM-34 for MiG pilots with a throat microphone Oxygen mask KM-34.jpg
Oxygen mask KM-34 for MiG pilots with a throat microphone
Throat microphone LA-5 (Soviet Union early 1980s), same model as above LA 5 throat microphone.jpg
Throat microphone LA-5 (Soviet Union early 1980s), same model as above
A general-purpose throat mic used for two-way radio communications TTT-HEAD.png
A general-purpose throat mic used for two-way radio communications

A throat microphone, also called a laryngophone, is a type of contact microphone that absorbs vibrations directly from the wearer's throat by way of single or dual sensors worn against the neck. The sensors, called transducers, can pick up speech even in extremely noisy or windy environments, such as on a motorcycle or in a nightclub. Other types of microphones do not function well under these conditions because of high levels of background noise. Advanced laryngophones are able to pick up whispers, and therefore perform well in environments where communicating with others at a distance in silence is required, such as during covert military or law enforcement operations. Throat microphones are also very useful when helmets or respiratory protection is required. Many full-face SCBA, CABA, SAR Respirator, Elastomeric Respirator, N95 Respirator PAPR, or re-breather masks do not have a provision for a microphone inside the mask. The throat microphone can be used safely, as it is positioned outside the mask's face seal and as such does not compromise the respiratory protection provided by the mask, nor does it violate mask approvals and certification.

Contents

Operation

A contact microphone is fastened to the neck below the larynx and records a signal related to the sound in the trachea. [1] The contact microphone senses the vibration in the wall of the neck. These vibrations reflect the mechanical shocks that result from the closing of the glottis and the variations of the subglottic pressure. This results from the interrupted transglottal airflow. [2]

A contact microphone can also be known as an accelerometer microphone. This is fastened below the larynx to produce a signal that is related to the vocal fold vibrations and the sound pressure in the trachea. The waveform produced by the contact microphone is usually independent on articulation. This is due to the high glottal impedance. The signal produced by the contact microphone measures fundamental frequency. The contact microphone is a simple accelerometer containing a piezo-electric ceramic disc as the pick-up unit. The disc is enclosed in a metal container of 15 mm in diameter and 5 mm in thickness and weighs about 20 grams. [3] The military could really benefit from the contact microphone in multiple different ways. The ways the contact microphone could be beneficial are it would not interfere with oxygen equipment, wouldn't affect speech intelligibility, injuries to the mouth and teeth would minimize, could observe lip movement, and certain pick up locations are better for noise shielding. [4]

History

World War I – first throat mics

Charles Edmond Prince lead the development of throat microphones for the British during World War I for use in the noisy and windy environment of aircraft cockpits. Over a 3 year period from 1915-1918 they went through a series of prototype and production handheld "airplane telephones" before arriving at a hands free throat mic incorporated into a leather flying helmet. [5] [6]

World War II – full body suits

During World War II, German Luftwaffe pilots [7] :176 and panzer crews used throat microphones. Soon after, they were adopted by the Allied air forces—the USAAF with the T-20 and T-30 and the RAF with the Mark II. Later, Soviet pilots relied on LA-3 and LA-5 models. [8]

Scientific studies

Starting in the 1970s, researchers explored the use of throat microphones in speech therapy. [9]

Current use

Throat microphones have maintained their presence in the military, law enforcement, and emergency services. Newer single-transducer designs are available that make the throat microphone much more comfortable to wear than earlier units and also better balance transmission quality. Additionally, this next generation of throat microphones provides varying outputs and frequency responses to accommodate a wide variety of professional communication devices such as digital and analog portable radios and Terrestrial Trunked Radio (TETRA) and P25 systems.

Several throat microphones including wireless throat mics now exist for mobile devices. [10] Mobile device apps are starting to allow further customisation for end-user applications. Consumer uses such as for airsoft competitions[ citation needed ] and motorcycle riding are increasingly more popular. [11] With COVID-19 and higher rate of face mask usage throat mics for general use is becoming more common to facilitate communications.

See also

Notes

  1. Askenfelt, A. and Gauffin, J. and Kitzing, P. and Sundberg J. (1977). "Electroglottograph And Contact Microphone For Measuring Vocal Pitch" (PDF). STL-QPSR. 18: 013–021 via KTH Computer Science And Communication.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. Askenfelt, Anders; Gauffin, Jan; Sundberg, Johan; Kitzing, Peter (June 1980). "A Comparison of Contact Microphone and Electroglottograph for the Measurement of Vocal Fundamental Frequency". ASHA Wire. doi:10.1044/jshr.2302.258 . Retrieved 2022-04-07.
  3. Askenfelt, Anders; Gauffin, Jan; Sundberg, Johan; Kitzing, Peter (June 1980). "A Comparison of Contact Microphone and Electroglottograph for the Measurement of Vocal Fundamental Frequency". ASHA Wire. doi:10.1044/jshr.2302.258 . Retrieved 2022-04-24.
  4. Snidecor, John C.; Rehman, Irving; Washburn, David D. (2018-12-28). "Speech Pickup by Contact Microphone at Head and Neck Positions". ASHA Wire. doi:10.1044/jshr.0203.277 . Retrieved 2022-04-24.
  5. The National Archives, Fighting talk: First World War telecommunications
  6. IEEE Spectrum, In World War I, British Biplanes Had Wireless Phones in the Cockpit
  7. Reitsch, H., 1955, The Sky My Kingdom, London: Biddles Limited, Guildford and King's Lynn, ISBN   1853672629
  8. "Throat Microphone Accessories". Vocomotion.
  9. Dewar, Dewar, and Barnes (1976). "Automatic triggering of auditory feedback masking in stammering and cluttering". The British Journal of Disorders of Communication. 11 (1): 19–26. PMID   938616.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. "Bluetooth Wireless Throat Mic". IASUS Concepts.
  11. "Motorcycle use of throat mics". Web Bike World.

Related Research Articles

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This is a glossary of medical terms related to communication disorders which are psychological or medical conditions that could have the potential to affect the ways in which individuals can hear, listen, understand, speak and respond to others.

Microphone Device that converts sound into an electrical signal

A microphone, colloquially called a mic or mike, is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. They are also used in computers for recording voice, speech recognition, VoIP, and for other purposes such as ultrasonic sensors or knock sensors.

The field of articulatory phonetics is a subfield of phonetics that studies articulation and ways that humans produce speech. Articulatory phoneticians explain how humans produce speech sounds via the interaction of different physiological structures. Generally, articulatory phonetics is concerned with the transformation of aerodynamic energy into acoustic energy. Aerodynamic energy refers to the airflow through the vocal tract. Its potential form is air pressure; its kinetic form is the actual dynamic airflow. Acoustic energy is variation in the air pressure that can be represented as sound waves, which are then perceived by the human auditory system as sound.

Vocal cord nodules are bilaterally symmetrical benign white masses that form at the midpoint of the vocal folds. Although diagnosis involves a physical examination of the head and neck, as well as perceptual voice measures, visualization of the vocal nodules via laryngeal endoscopy remains the primary diagnostic method. Vocal fold nodules interfere with the vibratory characteristics of the vocal folds by increasing the mass of the vocal folds and changing the configuration of the vocal fold closure pattern. Due to these changes, the quality of the voice may be affected. As such, the major perceptual signs of vocal fold nodules include vocal hoarseness and breathiness. Other common symptoms include vocal fatigue, soreness or pain lateral to the larynx, and reduced frequency and intensity range. Airflow levels during speech may also be increased. Vocal fold nodules are thought to be the result of vocal fold tissue trauma caused by excessive mechanical stress, including repeated or chronic vocal overuse, abuse, or misuse. Predisposing factors include profession, gender, dehydration, respiratory infection, and other inflammatory factors.

Laryngectomy

Laryngectomy is the removal of the larynx and separation of the airway from the mouth, nose and esophagus. In a total laryngectomy, the entire larynx is removed. In a partial laryngectomy, only a portion of the larynx is removed. Following the procedure, the person breathes through an opening in the neck known as a stoma. This procedure is usually performed by an ENT surgeon in cases of laryngeal cancer. Many cases of laryngeal cancer are treated with more conservative methods. A laryngectomy is performed when these treatments fail to conserve the larynx or when the cancer has progressed such that normal functioning would be prevented. Laryngectomies are also performed on individuals with other types of head and neck cancer. Post-laryngectomy rehabilitation includes voice restoration, oral feeding and more recently, smell and taste rehabilitation. An individual's quality of life can be affected post-surgery.

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Hoarse voice Voice disorder

A hoarse voice, also known as dysphonia or hoarseness, is when the voice involuntarily sounds breathy, raspy, or strained, or is softer in volume or lower in pitch. A hoarse voice, can be associated with a feeling of unease or scratchiness in the throat. Hoarseness is often a symptom of problems in the vocal folds of the larynx. It may be caused by laryngitis, which in turn may be caused by an upper respiratory infection, a cold, or allergies. Cheering at sporting events, speaking loudly in noisy situations, talking for too long without resting one's voice, singing loudly, or speaking with a voice that's too high or too low can also cause temporary hoarseness. A number of other causes for losing one's voice exist, and treatment is generally by resting the voice and treating the underlying cause. If the cause is misuse or overuse of the voice, drinking plenty of water may alleviate the problems.

Boundary microphone Microphone for use on or near a surface

A boundary microphone is one or more small omnidirectional or cardioid condenser mic capsule(s) positioned near or flush with a boundary (surface) such as a floor, table, or wall. The capsule(s) are typically mounted in a flat plate or housing. The arrangement provides a directional half-space pickup pattern while delivering a relatively phase-coherent output signal.

Throat singing refers to several vocal practices found in different cultures around the world. The most distinctive feature of such vocal practices is to be associated to some type of guttural voice, that contrasts with the most common types of voices employed in singing, which are usually represented by chest (modal) and head registers. Also, throat singing is often described as producing the sensation of more than one pitch at a time, i.e., the listener perceives two or more distinct musical notes, while the singer is producing a single vocalization.

Electronic fluency device

Electronic fluency devices are electronic devices intended to improve the fluency of persons who stutter. Most electronic fluency devices change the sound of the user's voice in his or her ear.

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Flight helmet

A flight helmet, sometimes referred to as a "bone dome" or "foam dome", is a special type of helmet primarily worn by military aircrew.

Electroglottograph

The electroglottograph, or EGG, is a device used for the noninvasive measurement of the degree of contact between the vibrating vocal folds during voice production. Though it is difficult to verify the assumption precisely, the aspect of contact being measured by a typical EGG unit is considered to be the vocal fold contact area (VFCA). To measure VFCA, electrodes are applied on the surface of the neck so that the EGG records variations in the transverse electrical impedance of the larynx and nearby tissues by means of a small A/C electric current. This electrical impedance will vary slightly with the area of contact between the moist vocal folds during the segment of the glottal vibratory cycle in which the folds are in contact. However, because the percentage variation in the neck impedance caused by vocal fold contact can be extremely small and varies considerably between subjects, no absolute measure of contact area is obtained, only the pattern of variation for a given subject.

Lombard effect

The Lombard effect or Lombard reflex is the involuntary tendency of speakers to increase their vocal effort when speaking in loud noise to enhance the audibility of their voice. This change includes not only loudness but also other acoustic features such as pitch, rate, and duration of syllables. This compensation effect maintains the auditory signal-to-noise ratio of the speaker's spoken words.

Setcom Corporation is an American manufacturer of communications equipment for police motorcycle officers, firefighters, rescue personnel and industrial users. Setcom supplies public safety professionals in all fifty states, most major US cities, and more than twenty countries with communications equipment.

Undertone singing is a set of singing techniques in which the vocalist makes use of vibrations of the vocal apparatus in order to produce subharmonic tones below the bass tone and extend the vocal range below the limits of the modal voice. In particular, the sound is produced via constricting the larynx in order to produce oscillations in the vocal cords and vestibular folds at certain frequencies of the vocal cords - corresponding to integer divisions of the frequency produced by the vestibular folds, such as 1:2, 1:3, and 1:4 ratios. This will produce the corresponding subharmonic to that frequency. For example, in a 1:2 ratio, each second vibration of the vocal folds, the vestibular fold will complete a single vibration cycle which will result in an subharmonic produced an octave below the bass tone produced by the vocal cords. This technique is attested in Buddhist Chant as well as Mongolian Throat Singing and is often used in conjunction with other vocal techniques such as vocal fry. The technique produces a deep, growling quality.