Thursday, September 29, 2:15 pm — 3:45 pm (Rm 403B)
P5-1 Combined Inverse Filtering and Feedback Control for Robust Equalization and Distortion Reduction in Loudspeaker Systems—Yusuke Kadowaki, Kyushu University - Kyushu, Japan; Toshiya Samejima, Kyushu University - Kyushu, Japan
A method for the robust equalization and distortion reduction of loudspeakers is proposed. The proposed method adopts both an IIR-type inverse filter and a feedback control. The feedback control based on model-following control theory is used to force a loudspeaker to move as a linear time-invariant (LTI) system. Accordingly, we expect the inverse filter that is specifically designed for the LTI system to work correctly. Furthermore, nonlinear distortion of a loudspeaker is expected to be reduced. Computer simulation shows that the proposed method achieves more robust equalization of a loudspeaker than inverse filtering alone. In addition, the proposed method simultaneously reduces nonlinear distortion of the loudspeaker.
Convention Paper 9608 (Purchase now)
P5-2 Investigation of Impulse Response Recording Techniques in Binaural Rendering of Virtual Acoustics—Kaushik Sunder, McGill University - Montreal, Quebec, Canada; Centre for Interdisciplinary Research in Music Media dn Technology (CIRMMT) - Montreal, Quebec, Canada; Wieslaw Woszczyk, McGill University - Montreal, QC, Canada
With the advent of virtual reality headsets, accurate rendering of the acoustics of the real space is critical to deliver a truly immersive experience. To ensure the veracity of immersion, there is a need to obtain high quality impulse responses that captures all the relevant acoustical features of the space. In this work we investigate and compare the perception of virtual acoustics rendered over headphones using impulse responses captured with (a) binaural dummy-head, and (b) multichannel (8-channel) microphone array. A downmixing algorithm is developed that converts the free-field 8-channel impulse responses to binaural for rendering over headphones. Subjective experiments suggest higher quality of immersion with reconstructed binaural from multichannel room impulse responses compared to the measured binaural room impulse responses. This investigation provides important information in understanding the essential elements in creating a convincing perception of an acoustic space.
Convention Paper 9609 (Purchase now)
P5-3 New Recording Application for Software Defined Media—Masahiro Ikeda, Yamaha Corporation - Hamamatsu, Shizuoka, Japan; Takuro Sone, Yamaha Corporation - Shizuoka, Japan; Kenta Niwa, NTT Media Inelligence Laboratories - Tokyo, Japan; Shoichiro Saito, NTT Media Intelligence Laboratories - Tokyo, Japan; Manabu Tsukada, University of Tokyo - Tokyo, Japan; Hiroshi Esaki, University of Tokyo - Tokyo, Japan
In recent years, hardware-based systems are becoming software-based and networked. From IP based media networks, the notion of Software Defined Media (SDM) has arisen. SDM is an architectural approach to media as a service by virtualization and abstraction of networked infrastructure. With this approach, it would be possible to provide more flexible and versatile systems. To test this concept, a baroque orchestra was recorded by various methods with 82 channels of microphones in total. All the data was organized based on the object-based concept and we applied advanced signal processing to the data based on array signal processing technology to produce a content matching various purposes of possible applications. Through this study, the value of SDM concept is verified.
Convention Paper 9610 (Purchase now)
P5-4 Interference Evaluation of Parametric Loudspeakers on Digital Hearing Aids—Santi Peksi, Nanyang Technological University - Singapore; Woon-Seng Gan, Nanyang Technological University - Singapore, Singapore; Dong-Yuan Shi, Nanyang Technological University - Singapore; Satya Vijay Reddy Medapati, Tan Tock Seng Hospital - Singapore; Eu-Chin Ho, Tan Tock Seng Hospital - Singapore
Parametric loudspeakers are able to generate a highly-directional sound, and recently it has also been used to help the hearing impaired to hear TV programs better. However, there are incidents that particular hearing aid users have reported audible interferences in the path of directional sound beams during the clinical trials. The interference varies from buzzing noise to static noise for various commercialized behind-the-ear (BTE) hearing aids. To investigate the audible interference, hearing aid output measurements were carried out using B&K Head and Torso Simulators (HATS) inside an anechoic room at various distances for four types of parametric loudspeakers. This paper also investigates its possible cause of interference and raises awareness to professionals on potential audible interference on hearing aids using parametric loudspeakers.
Convention Paper 9611 (Purchase now)