A qualitative and quantitative analysis of impulse responses from balloon bursts

Cheenne, Dominique J.; Ardila, Mauricio; Lee, Connie G.; Bridgewater, Ben

doi:10.1121/1.2935906

Cited by 6 publications

(3 citation statements)

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“…Also in the same study there seemed to be evidence that there are variations in actual directivity as a function of inflation levels. Similar results about the omnidirectionality have been reported by Griesinger [71] and Cheenne et al [72]. Schlieren imaging of a balloon burst [73] reveals that the shock front is not quite spherical.…”

Section: Balloonsupporting

confidence: 88%

“…Consistent inflations levels were evaluated by measuring the maximum width diameter with a 1 cm margin of error. Also a study by Cheenne et al [72], where anechoic recordings of balloon bursts were systematically acquired for various conditions of balloon diameters, puncture location and inflation pressure, reports that the results are quite consistent when averaged over one-third octave bands. However it seems both the results found in the studies of Griesinger [71] and Cheenne et al [72] are difficult to replicate in real-life measurements in order to achieve similar results.…”

Section: Balloonmentioning

confidence: 85%

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Review of Acoustic Sources Alternatives to a Dodecahedron Speaker

Papadakis

Stavroulakis

2019

Applied Sciences

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An omnidirectional source is required in many acoustic measurements. Commonly a dodecahedron speaker is used but due to various factors (e.g., high cost, transportation difficulties) other acoustic sources are sometimes preferred. In this review, fifteen acoustic source alternatives to a dodecahedron speaker are presented while emphasis is placed on features such as omnidirectionality, repeatability, adequate sound pressure levels, even frequency response, accuracy in measurement of acoustic parameters and fulfillment of ISO 3382-1 source requirements. Some of the alternative acoustic sources have the appropriate features to provide usable results for acoustic measurements, some have acoustic characteristics better than a dodecahedron speaker (e.g., omnidirectionality in the high-frequency range), while some can potentially fulfill the ISO 3382-1 source requirements. Collected data from this review can be used in many areas (e.g., ISO measurements, head-related transfer functions measurements) for the appropriate selection of an acoustic source according to the expected use. Finally, suggestions for uses and future work are given aimed at achieving further advances in this field.

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Section: Balloonsupporting

confidence: 88%

Section: Balloonmentioning

confidence: 85%

Review of Acoustic Sources Alternatives to a Dodecahedron Speaker

Papadakis

Stavroulakis

2019

Applied Sciences

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“…An impulsive sound was generated by bursting a balloon to measure T. Although it is a sound source that presents certain drawbacks, such as directional sound radiation at some frequencies (35)(36)(37), it was chosen because its size can be adapted to the size of the incubator, and because it matches the conditions of the ISO 3382-2 for omnidirectional sources at frequencies above 500 Hz (35). To get uniform impulsive sounds, balloons of similar diameter, brand, color, and air inflation volume were burst (35,37,38). No criterion was found in the literature for the number of sound source positions used for small enclosures: It was decided to use two sound source positions, meeting the recommendations of the ISO 3382-2 for the engineering level of measurement accuracy.…”

Section: Methodsmentioning

confidence: 99%

The Importance of Reverberation for the Design of Neonatal Incubators

et al. 2021

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Low frequency noises are predominant in neonatal intensive care units (NICUs). Some studies affirm that neonates can perceive noises from 113 Hz, and can therefore be affected by sound sources with high spectral content at low frequencies (e.g., incubator engine, air fan). Other studies suggest that reverberation amplifies noise within incubators. In this paper, the reverberation time (T, T30) within an incubator with standard dimensions was measured in one-third octave bands. To get reliable results, the T was measured in 15 positions at the neonate's ear height, in a room with low T values (to reduce the influence of the room in the results), using an impulsive sound method. Results show a heterogeneous T distribution at the neonate's ear height, with maximum average T differences between positions of 1.07 s. The highest average T of all microphone positions is 2.27 s at 125 Hz, an extremely high mean value for such a small space. As the frequency of electrical devices in America is 60 Hz, some harmonics lay within the one-third octave band of 125 Hz, and therefore may create a very reverberant and inappropriate acoustic environment within the audible spectrum of neonates. As the acoustic environment of the incubator and the room are coupled, it is expected that the results are higher in the NICUs than in the room where the measurements were conducted, as NICUs are more reverberant. Therefore, it is recommended that the T will be limited in the international standards, and that incubator designers take it into account.

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