Influence of “omnidirectional” loudspeaker directivity on measured room impulse responses

Knüttel, Tobias; Witew, Ingo B.; Vorländer, Michael

doi:10.1121/1.4824334

Cited by 25 publications

(21 citation statements)

References 7 publications

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“…The minimum distance between source and microphone shall be 1.5 m during these measurements. However some concerns have been expressed about measuring the directivity according to those standards [23][24][25]. Also, a new descriptor for measuring the directivity of dodecahedron speakers and omnidirectional sound sources has been proposed [26].…”

Section: Requirements For Omnidirectional Sourcesmentioning

confidence: 99%

“…Correspondingly, the frequency response of the loudspeaker will feature frequency response irregularities [35]. It has to be noted that these deviations from omnidirectionality have an effect on the measurement of the impulse response and acoustic parameters of a space [24,25].…”

Section: Drawbacks Of Dodecahedron Speakersmentioning

confidence: 99%

“…Omnidirectionality ensures uniform space excitation necessary for correct impulse response measurement. The directivity of the source influence the measurement of impulse responses and acoustic parameters of spaces [24,25]. For each source, we have collected various research that have investigated the directivity of the source in accordance with ISO 3382-1 or with more general criteria.…”

Section: Acoustic Source Alternatives To a Dodecahedron Speakermentioning

confidence: 99%

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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: Requirements For Omnidirectional Sourcesmentioning

confidence: 99%

Section: Drawbacks Of Dodecahedron Speakersmentioning

confidence: 99%

Section: Acoustic Source Alternatives To a Dodecahedron Speakermentioning

confidence: 99%

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Review of Acoustic Sources Alternatives to a Dodecahedron Speaker

Papadakis

Stavroulakis

2019

Applied Sciences

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“…A special aspect of our work is that the measurements are made in a typical real-world environment rather than an anechoic chamber or in an ideal setup of any kind. Moreover, the variations in the response reported predict only on axis response [2] and concentrate on directivity [3,4]. In an anechoic chamber, the placement or position of radiators is ideal, whereas in the real-world scenario, the placement of the radiator is critical, as it produces a variety of reflections depending on the enclosure.…”

Section: Introductionmentioning

confidence: 99%

Near Direct and Far Reverberant Field Response of Direct Radi ator Loudspeakers

Godase*,

Surve

2019

IJEAT

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Typical audience seating arrangements in rooms and auditoria warrant reinvestigation of the direct radiator speaker response in the near-direct and far-reverberant fields, as the response data provided by the manufacturer is always ideal and does not account for the effect of those fields. The speaker response characteristics of a variety of direct radiator loudspeakers ranging from the conventional squawker to the full range radiator have been investigated in these fields. The speaker response is investigated in the 50 -10 kHz frequency range, by measuring the A-weighted SPL (sound pressure level) in the near-direct and far-reverberant fields, using an acoustic analyzer. The field-specific characteristic for each of the radiators is determined by fitting the SPL data obtained to an appropriate polynomial. The coefficients obtained thereby, allow an objective field-specific study amongst radiators. When a set of direct radiator loudspeakers is available, it is necessary to configure their application, depending upon the optimum sound quality required for a given enclosure, in near-direct field and far-reverberant field. The outcome of this work assists one to configure the best radiator ensemble for a given enclosure, despite placement constraints.

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“…The effect of the multidirectional radiation decreases the accuracy of the measured responses. 5 Moreover, loudspeakers feature a finite volume that may shadow or reflect sound. For these reasons, miniature loudspeakers cannot be regarded as a true monopole source.…”

Section: Introductionmentioning

confidence: 99%

Spectral density affects the intelligibility of tone-vocoded speech: Implications for cochlear implant simulations

Rosen

Zhang

Speers

2015

The Journal of the Acoustical Society of America

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For small numbers of channels, tone vocoders using low envelope cutoff frequencies are less intelligible than noise vocoders, even though the noise carriers introduce random fluctuations into the crucial envelope information. Here it is shown that using tone carriers with a denser spectrum improves performance considerably over typical tone vocoders, at least equaling, and often surpassing, the performance possible with noise vocoders. In short, the spectral sparseness of tone vocoded sounds for low channel numbers, separate from the degradations introduced by using only a small number of channels, is an important limitation on the intelligibility of tone-vocoded speech.

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Influence of “omnidirectional” loudspeaker directivity on measured room impulse responses

Cited by 25 publications

References 7 publications

Review of Acoustic Sources Alternatives to a Dodecahedron Speaker

Review of Acoustic Sources Alternatives to a Dodecahedron Speaker

Near Direct and Far Reverberant Field Response of Direct Radi ator Loudspeakers

Spectral density affects the intelligibility of tone-vocoded speech: Implications for cochlear implant simulations

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