The Physics of Sound

Berg, Richard E.; Stork, David G.; Holmes, Brian

doi:10.1119/1.12960

Cited by 32 publications

(34 citation statements)

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“…Tension across the microphone membrane is constant, as expected for an isotropic membrane (Berg and Stork, 1995). For the moth, membrane tension greatly varies across the transect.…”

Section: Discussionmentioning

confidence: 63%

Mechanics of a `simple' ear: tympanal vibrations in noctuid moths

Windmill

Fullard

Robert

2007

Journal of Experimental Biology

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SUMMARY Anatomically, the ears of moths are considered to be among the simplest ears found in animals. Microscanning laser vibrometry was used to examine the surface vibrations of the entire tympanal region of the ears of the noctuid moths Agrotis exclamationis, Noctua pronuba, Xestia c-nigrum and Xestia triangulum. During stimulation with ultrasound at intensities known to activate receptor neurones, the tympanum vibrates with maximum deflection amplitudes at the location where the receptor cells attach. In the reportedly heterogeneous tympana of noctuid moths, this attachment site is an opaque zone that is surrounded by a transparent, thinner cuticular region. In response to sound pressure, this region moves relatively little compared with the opaque zone. Thus, the deflections of the moth tympanic membrane are not those of a simple circular drum. The acoustic sensitivity of the ear of N. pronuba, as measured on the attachment site, is 100±14 nm Pa–1 (N=10), corresponding to tympanal motion of a mere 200 pm at sound pressure levels near the neural threshold.

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“…Tension across the microphone membrane is constant, as expected for an isotropic membrane (Berg and Stork, 1995). For the moth, membrane tension greatly varies across the transect.…”

Section: Discussionmentioning

confidence: 63%

Mechanics of a `simple' ear: tympanal vibrations in noctuid moths

Windmill

Fullard

Robert

2007

Journal of Experimental Biology

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“…Figure 3 shows the parameters associated with air resonance in a closed cylinder [7,8] . An important method of processing and analyzing a sound signal is to look at the signal's frequency content.…”

Section: Methodsmentioning

confidence: 99%

“…Cents is calculated using the relationship: with ¢ is cents, f 1 is the reference frequency and f 2 is the interested frequency value [5][6][7] .…”

Section: Methodsmentioning

confidence: 99%

Pitch and Timbre Determination of the Angklung

Zainal¹,

Samad²,

Hussain³

et al. 2009

American J. of Applied Sciences

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This research describes the pitch and timbre determination of the angklung, a musical instrument made entirely out of bamboo. An angklung has two main parts: the frame and the rattle tubes. The pitch of the rattle tubes can be determined using a formula that takes into consideration the length and diameter of the air resonator. This is compared with the results obtained using sound analysis with the fast Fourier transform as well as with measured results. The coupling effects of having two rattles on the pitch and timbre are investigated. It is found that the pitch of the angklung is closely related to the fundamental frequency of air resonance in the bamboo tubes of the angklung rattles. Therefore, the pitch of an angklung can be estimated by calculating that fundamental frequency using information from the length and diameter of the closed cylinder air column of each rattle. The timbre of the angklung is also determined to be a mix of the sound output from each of its individual rattles. The timbre has an identifying characteristic of having two prominent peaks with each one corresponding to the pitch of each rattle.

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“…The classical way of testing a cavity for quench spots is the use of arrays of thermocouples, which are moved around the cavity in operation. Quench spots can be localized to within 2-3 cm, but ''the process of locating defects in 9 cell cavities remains a lengthy and cumbersome process'' [7]. Practically, it cannot be applied on the thousands of ILC cavities.…”

Section: Introductionmentioning

confidence: 99%

“…15. Graphic representation of the eigenmodes of an oscillating circular membrane with the smallest frequencies; figure adopted according to[7].FIG 16…”

mentioning

confidence: 99%

Response of an oscillating superleak transducer to a pointlike heat source

Quadt

Schröder

Uhrmacher

et al. 2012

Phys. Rev. ST Accel. Beams

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A new technique of superconducting cavity diagnostics has been introduced by D. L. Hartill at Cornell University, Ithaca, New York. It uses oscillating superleak transducers (OST) which detect the heat transferred from a cavity's quench point via Second Sound through the superfluid He bath, needed to cool the superconducting cavity. The localization of the quench point is done by triangulation. The observed response of an OST is a nontrivial, but reproducible pattern of oscillations. A small helium evaporation cryostat was built which allows the investigation of the response of an OST in greater detail. The distance between a pointlike electrical heater and the OST can be varied. The OST can be mounted either parallel or perpendicular to the plate that houses the heat source. If the artificial quench point releases an amount of energy compatible to a real quench spot on a cavity's surface, the OST signal starts with a negative pulse, which is usually strong enough to allow automatic detection. Furthermore, the reflection of the Second Sound on the wall is observed. A reflection coefficient R ¼ 0:39 AE 0:05 of the glass wall is measured. This excludes a strong influence of multiple reflections in the complex OST response. Fourier analyses show three main frequencies, found in all OST spectra. They can be interpreted as modes of an oscillating circular membrane.

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The Physics of Sound

Cited by 32 publications

References 0 publications

Mechanics of a `simple' ear: tympanal vibrations in noctuid moths

Mechanics of a `simple' ear: tympanal vibrations in noctuid moths

Pitch and Timbre Determination of the Angklung

Response of an oscillating superleak transducer to a pointlike heat source

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