AES New York 2019
Engineering Brief EB2

EB2 - Posters: Applications in Audio

Friday, October 18, 9:00 am — 10:30 am

EB2-1 Personal Audio Systems in Car Cabin Using Loudspeaker Array Based on Measured Transfer Functions with Spectral SmoothingYefeng Cai, Colsonic Electronics Co., Ltd. - Suzhou, China; Chao Ye, Colsonic Electronics Co., Ltd. - Suzhou, China; Dengyong Ma, Colsonic Electronics Co., Ltd. - Suzhou, China; Yongsheng Mu, Colsonic Electronics Co., Ltd. - Suzhou, China; Jianming Zhou, Suzhou Sonavox electronics Co., Ltd. - Suzhou, China; Guoqiang Chai, Suzhou Sonavox Electronics Co.,Ltd - Suzhou, China
Personal audio systems in the car cabin are used to divide the listening space into several isolated sound zones. However, the system performance is usually deteriorated due to the complex acoustic propagation characteristics. In attempt to reduce this effect, linearly constrained minimum variance approach using the measured transfer functions with spectral smoothing is proposed. Real-time experiments with loudspeaker array composed of 24 loudspeaker units are conducted in a real car cabin, and it is demonstrated that the performance of contrast could be improved at the whole frequency range [200, 1500] Hz, on condition that the measured transfer functions are preprocessed by amplitude smoothing.
Engineering Brief 528

EB2-2 A Latency Measurement Method for Networked Music PerformancesRobert Hupke, Leibniz Universität Hannover - Hannover, Germany; Sripathi Sridhar, New York University - New York, NY, USA; Andrea Genovese, New York University - New York, NY, USA; Marcel Nophut, Leibniz Universität Hannover - Hannover, Germany; Stephan Preihs, Leibniz Universität Hannover - Hannover, Germany; Tom Beyer, New York University - New York, NY, USA; Agnieszka Roginska, New York University - New York, NY, USA; Jürgen Peissig, Leibniz Universität Hannover - Hannover, Germany
The New York University and the Leibniz University Hannover are working on future immersive Networked Music Performances. One of the biggest challenges of audio data transmission over IP-based networks is latency, which can affect the interplay of the participants. In this contribution, two metronomes, utilizing the Global Positioning System to generate a globally synchronized click signal, were used as a tool to determine delay times in the data transmission between both universities with high precision. The aim of this ?rst study is to validate the proposed method by obtaining insights into transmission latency as well as latency ?uctuations and asymmetries. This work also serves as baseline for future studies and helps to establish an effective connection between the two institutions.
Engineering Brief 529

EB2-3 An Investigation into the Effectiveness of Room Adaptation Systems: Listening Test ResultsPei Yu, Nanjing University - Nanjing, China; Ziyun Liu, Nanjing University - Nanjing, China; Shufeng Zhang, Nanjing University - Nanjing, China; Yong Shen, Nanjing University - Nanjing, Jiangsu Province, China
Loudspeaker-room interactions are well known for affecting the perceived sound quality of low frequencies. To solve this problem, different room adaptation systems for adapting a loudspeaker to its acoustic environment have been developed. In this study two listening tests were performed to assess the effectiveness of four different room adaptation systems under different circumstances. The factors investigated include the listening room, loudspeaker, listening position, and listener. The results indicate that listeners’ preference for different adaptation systems is affected by the specific acoustic environment. It was found that the adaptation system based on acoustic power measurement proved to be more preferred, also with stable performance.
Engineering Brief 530

EB2-4 Evaluating Four Variants of Sine Sweep Techniques for Their Resilience to Noise in Room Acoustic MeasurementsEric Segerstrom, Rensselaer Polytechnic Institute - Troy, NY, USA; Ming-Lun Lee, University of Rochester - Rochester, NY, USA; Steve Philbert, University of Rochester - Rochester, NY, USA
The sine sweep is one of the most effective methods for measuring room impulse responses; however, ambient room noise or unpredictable impulsive noises can negatively affect the quality of the measurement. This study evaluates four different variants of sine sweeps techniques for their resilience to noise when used as an excitation signal in room impulse response measurements: linear, exponential, noise whitened, and minimum noise. The result shows that in a pseudo-anechoic environment, exponential and linear sine sweeps are most resilient to impulsive noise among the four sweeps, while none of the evaluated sine sweeps are resilient to impulsive noise in an acoustically untreated room. Additionally, it is shown that minimum noise sine sweeps are most resilient to ambient noise.
Engineering Brief 531

EB2-5 Perceptually Affecting Electrical Properties of Headphone Cable – Factor Hunting ApproachAkihiko Yoneya, Nagoya Institute of Technology - Nagoya, Aichi-pref., Japan
An approach to find the cause of the perceptual sound quality change by headphone cable has been proposed. This is a method of verifying the validity of the selected candidate by selecting candidate factors from the measurement results, simulating them by digital signal processing, and evaluating the simulated sounds by audition. In the headphone cable, it was found that the factor is that the inductance changes due to the flowing current. It has become clear from the experimental results that changes in transfer characteristics are very sensitively affecting the perceptual sound quality.
Engineering Brief 532

EB2-6 An Investigation into the Location and Number of Microphone Measurements Necessary for Efficient Active Control of Low-Frequency Sound Fields in Listening RoomsTom Bell, Bowers & Wilkins - Southwater, West Sussex, UK; University of Southampton - Southampton, Hampshire, UK; Filippo Maria Fazi, University of Southampton - Southampton, Hampshire, UK
The purpose of this investigation is to understand the minimum number of control microphone measurements needed and their optimal placement to achieve effective active control of the low-frequency sound field over a listening area in a rectangular room. An analytical method was used to model the transfer functions the loudspeakers and a 3-dimensional array of 75 virtual microphones. A least-squares approach was used to create one filter per sound source from a varying number and arrangement of these measurements, with the goal to minimize the error between the reproduced sound field and the target. The investigation shows once enough measurements are taken there is a clear diminishing return in the effectiveness of the filters versus the number of measurements needed. [Presentation only; not in E-Library]

EB2-7 Measuring Speech Intelligibility Using Head-Oriented Binaural Room Impulse ResponsesAllison Lam, Tufts University - Medford, MA, USA; Ming-Lun Lee, University of Rochester - Rochester, NY, USA; Steve Philbert, University of Rochester - Rochester, NY, USA
Speech intelligibility/speech clarity is important in any setting in which information is verbally communicated. More specifically, a high level of speech intelligibility is crucial in classrooms to allow teachers to effectively communicate with their students. Given the importance of speech intelligibility in learning environments, several studies have analyzed how accurately the standard method of measuring clarity predicts the level of speech intelligibility in a room. In the context of speech measurements, C50 has been widely used to measure clarity. Instead of using a standard omnidirectional microphone to record room impulse responses for clarity measurements, this study examines the effectiveness of room impulse responses measured with a binaural dummy head. The data collected for this experiment show that C50 measurements differ between the left and right channels by varying amounts based on the dummy head’s position in the room and head orientation. To further investigate the effectiveness of binaural C50 measurements in comparison to the effectiveness of omnidirectional C50 measurements, this research explores the results of psychoacoustic testing to determine which recording method more consistently predicts human speech intelligibility. These results, combined with qualitative observations, predict how precisely acousticians are able to measure C50.
Engineering Brief 533

EB2-8 Compensation Filters for Excess Exciter Excursion on Flat-Panel LoudspeakersDavid Anderson, University of Pittsburgh - Pittsburgh, PA, USA
Inertial exciters are used to actuate a surface into bending vibration, producing sound, but often have a high-Q resonance that can cause the exciter magnet to displace enough to contact the bending panel. The magnet contacting the panel can cause distortion and possibly even damage to the exciter or panel while having a minimal contribution to acoustic output. A method is outlined for deriving a digital biquad filter to cancel out the excessive displacement of the magnet based on measurements of the exciter’s resonant frequency and Q-factor. Measurements of exciter and panel displacement demonstrate that an applied filter reduces magnet excursion by 20 dB at the resonant frequency.
Engineering Brief 534

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