AES Europe 2025: Full Schedule

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9:00am CEST

Extension of Reflection-Free Region for Loudspeaker Measurements

Saturday May 24, 2025 9:00am - 10:45am CEST

If loudspeaker measurements are carried out elevated over a flat, very reflective surface with no nearby obstacles, the recovered impulse response will contain the direct response and one clean delayed reflection. Many loudspeakers are omnidirectional at low frequencies, having a clear acoustic centre, and this reflection will have a low-frequency behaviour that is essentially the same as its direct response, except the amplitude will be down by a 1/r factor. We derive a simple algorithm that iteratively allows this reflection to be cancelled, so that the response of the loudspeaker will be valid to lower frequencies than before, complementing the usual high-frequency response obtained from simple time-truncation of the impulse response. The method is explained, discussed, and illustrated with a two-way system measured over a flat, sealed driveway surface.

Speakers

John Vanderkooy

Saturday May 24, 2025 9:00am - 10:45am CEST
Hall F ATM Studio Warsaw, Poland

Transducers & Measurements

Presentation Type Poster Presentation

9:00am CEST

Impact of Voice-Coil Temperature on Electroacoustic Parameters for Optimized Loudspeaker Enclosure Design in Small-Signal Response

Saturday May 24, 2025 9:00am - 10:45am CEST

Hall F

The study of electroacoustic parameters in relation to loudspeaker temperature has predominantly focused on large-signal conditions (i.e., high-power audio signals), with limited attention to their behavior under small-signal conditions at equivalent thermal states. This research addresses this gap by investigating the influence of voice-coil temperature on electroacoustic parameters during small-signal operation. The frequency response of the electrical input impedance and the radiated acoustic pressure were measured across different voice-coil temperatures. The results revealed temperature-dependent shifts across all parameters, including the natural frequency in free air (fₛ), mechanical quality factor (Qₘₛ), electrical resistance (Rₑ), electrical inductance (Lₑ), and equivalent compliance volume (Vₐₛ), among others. Specifically, Rₑ and Lₑ increased linearly with temperature, while fₛ decreased and Vₐₛ increased following power-law functions. These changes suggest that thermal effects influence both electrical and mechanical subsystems, potentially amplified by the viscoelastic “creep” effect inherent to loudspeaker suspensions. Finally, simulations of sealed and bandpass enclosures demonstrated noticeable shifts in acoustic performance under thermal variations, emphasizing the importance of considering temperature effects in enclosure design.

Speakers

Nicolás Quinteros

Víctor Espinoza

Saturday May 24, 2025 9:00am - 10:45am CEST
Hall F ATM Studio Warsaw, Poland

Transducers & Measurements

Presentation Type Poster Presentation

9:00am CEST

Material Characterization and Variability in Loudspeaker Membranes for Acoustic Modeling

Saturday May 24, 2025 9:00am - 10:45am CEST

Hall F

Finite Element Method (FEM) simulations are vital in the design of loudspeakers, offering a more efficient alternative to traditional trial-and-error approaches. Precise material characterization, however, is essential in ensuring that theoretical models align closely with measurements. Variations in material properties, particularly those of a loudspeaker’s membrane, can significantly influence loudspeaker performance. This work aims to establish a methodology for evaluating the variability of loudspeaker membrane materials, specifically cones and surrounds, to better understand each materials repeatability among samples, and overall improve the precision and reliability of loudspeaker simulations.

The study first conducts an in-depth analysis of membrane materials, focusing on their Young’s modulus and density, by utilizing both empirical and simulated data. Subsequently, complete loudspeakers were built and investigated, utilizing membranes studied. A FEM simulation framework is presented, and observations are made into discrepancies between measured and simulated loudspeaker responses at specific frequencies and their relation to material modeling.

The results demonstrated significant alignment between simulations and real-life performances, showing interesting insights into the impact of small changes in material properties on the acoustic response of a loudspeaker. One significant finding was the frequency dependence of the Young’s modulus of fiberglass used for a cone. Further validation can be achieved by expanding the dataset of the materials measured, exploring more materials, and under varying conditions such as temperature and humidity. Such insights enable more accurate modeling of loudspeakers and lay the groundwork for exploring novel materials with enhanced acoustic properties, guiding the development of high-performance loudspeakers.

Speakers

Adriane Elizabeth Replogle

Chiara Corsini

R&D engineer, FAITAL [ALPS ALPINE]

Chiara has joined Faital S.p.A. in 2018, working as a FEM analyst in the R&D Department. Her research activities are focused on thermal phenomena associated with loudspeaker functioning, and mechanical behavior of the speaker moving parts. To this goal, she uses FEM and lumped parameter... Read More →

Luca Villa

FAITAL [ALPS ALPINE]

Grazia Spatafora

Romolo Toppi

FAITAL [ALPS ALPINE]

Saturday May 24, 2025 9:00am - 10:45am CEST
Hall F ATM Studio Warsaw, Poland

Transducers & Measurements

Presentation Type Poster Presentation

9:00am CEST

Shape Optimization of Waveguides for Improving the Directivity of Soft Dome Tweeters

Saturday May 24, 2025 9:00am - 10:45am CEST

Hall F

This paper introduces a new algorithm for multiposition mixed-phase equalization of slot-loaded loudspeaker responses obtained in the horizontal and vertical plane, using finite impulse response (FIR) filters. The algorithm selects a {\em prototype response} that yields a filter that best optimizes a time-domain-based objective metric for equalization for a given direction. The objective metric includes a weighted linear combination of pre-ring energy, early and late reflection energy, and decay rate (characterizing impulse response shortening) during filter synthesis. The results show that the presented mixed-phase multiposition filtering algorithm performs a good equalization along all horizontal directions and for most positions in the vertical direction. Beyond the multiposition filtering capabilities, the algorithm and the metric are suitable for designing mixed-phase filters with low delays, an essential constraint for real-time processing.

Speakers

He Xiao

Jun Gu

Zhi Li

Jianbin Yang

Saturday May 24, 2025 9:00am - 10:45am CEST
Hall F ATM Studio Warsaw, Poland

Transducers & Measurements

Presentation Type Poster Presentation

9:00am CEST

Supervised Machine Learning for Quality Assurance in Loudspeakers: Time Distortion Analysis

Saturday May 24, 2025 9:00am - 10:45am CEST

Hall F

Measuring a speaker’s ability to respond to an instantaneous pulse of energy will result in distortion at its output. Factors such as speaker geometry, material properties, equipment error, and the conditions of the environment will create artifacts within the captured data. This paper explores the extraction of time-domain features from these responses, and the training of a predictive model to allow for classification and rapid quality assurance.

Speakers

Gregg O'Donnell

Saturday May 24, 2025 9:00am - 10:45am CEST
Hall F ATM Studio Warsaw, Poland

Transducers & Measurements

Presentation Type Poster Presentation