Friday, October 20, 2:00 pm — 3:30 pm
P15-1 Noise Shaping Scheme Suppressing Quantization Noise Amount—Akihiko Yoneya, Nagoya Institute of Technology - Nagoya, Aichi-pref., Japan
A noise shaping scheme for multi-bit pulse-code-modulation suppressing the amount of the quantization noise is proposed. In the case with ordinary digital processing or digital-to-analog converters, noise is added over the whole frequency range and the shaped quantization noise of the source signal may only make the total signal-to-noise ratio worse. Therefore the amount of the quantization noise is preferable to be small even if the noise spectrum is shaped. In the proposed method, magnitude of the quantization noise is restricted at each sample and the optimal additional quantization pattern over a receding horizon with respect to the specified perception filter is searched in the look-ahead sigma-delta modulator manner. The amplitude of the quantization noise may be about 0.72 LSB regardless of the perception filter with the proposed method but a higher order perception filter requires a wide horizon of the optimization and a huge amount of the computation. An example is presented.
Convention Paper 9883
P15-2 Evaluation of the Acoustics of the Roman Theater in Benevento for Discreet Listening Points—Gino Iannace, Università della Campania "Luigi Vanvitelli" - Aversa, Italy; Amelia Trematerra, Universitá della Campania "Luigi Vanvitelli" - Aversa, Italy
This work reports the acoustics of the Roman Theater in Benevento evaluated for discreet listening points positioned in the cavea in three radial directions. The theater, built in the second century A.D., was abandoned due to historical reasons and natural events. The recovery work ended in 1950. The theater is the center of important social activities. The theater acoustic measurements were taken by placing an omnidirectional spherical sound source on the stage and in the orchestra, with the microphone along three distinct radial directions on the steps of the cavea. The acoustic properties in the various seating areas were measured. The aim of the work is to evaluate in which sectors of the cavea the acoustic parameters are optimal for listening to different types of theatrical performances.
Convention Paper 9884
P15-3 Modeling the Effects of Rooms on Frequency Modulated Tones—Sarah R. Smith, University of Rochester - Rochester, NY, USA; Mark F. Bocko, University of Rochester - Rochester, NY, USA
This paper describes how reverberation impacts the instantaneous frequency tracks of modulated audio signals. Although this effect has been observed in a number of contexts, less work has been done relating these deviations to acoustical parameters of the reverberation. This paper details the instantaneous frequency deviations resulting from a sum of echoes or a set of resonant modes and emphasizes the conditions that maximize the resulting effect. Results of these models are compared with the observed instantaneous frequencies of musical vibrato tones filtered with the corresponding impulse responses. It is demonstrated that these reduced models may adequately reproduce the deviations when the signal is filtered by only the early or low frequency portion of a recorded impulse response.
Convention Paper 9885
P15-4 New Research on Low-Frequency Absorption Using Membranes—John Calder, Acoustic Geometry - Minneapolis, MN, USA
Room modes are one of the greatest concerns when considering accurate sound recording and reproduction. Low-frequency (LF) absorbers are used to mitigate modes, however, most independent testing laboratories are only large enough to measure accurate absorption results above 160 Hz but not below. One lab is large enough to be accurate down to 40 Hz. A new LF absorber was designed to complement the capabilities of an original LF absorber. Summary: the type of absorber, and its location and orientation in a room, are all critical to LF absorber effectiveness. Without standardized laboratory absorption testing in a lab capable of accurately testing down to 40 Hz, it is difficult to state conclusively that low-frequency absorber products perform as claimed.
Convention Paper 9886
P15-5 Analysis of Drum Machine Kick and Snare Sounds—Jordie Shier, University of Victoria - Victoria, Canada; Kirk McNally, University of Victoria, School of Music - Victoria, BC, Canada; George Tzanetakis, University of Victoria - Victoria, BC, Canada
The use of electronic drum samples is widespread in contemporary music productions, with music producers having an unprecedented number of samples available to them. The development of new tools to assist users organizing and managing libraries of this type requires comprehensive audio analysis that is distinct from that used for general classification or onset detection tasks. In this paper 4230 kick and snare samples, representing 250 individual electronic drum machines are evaluated. Samples are segmented into different lengths and analyzed using comprehensive audio feature analysis. Audio classification is used to evaluate and compare the effect of this time segmentation and establish the overall effectiveness of the selected feature set. Results demonstrate that there is improvement in classification scores when using time segmentation as a pre-processing step.
Convention Paper 9887
P15-6 Dynamic Range Controller Ear Training: Description of a Methodology, Software Application, and Required Stimuli—Denis Martin, McGill University - Montreal, QC, Canada; CIRMMT - Montreal, QC, Canada; George Massenburg, Schulich School of Music, McGill University - Montreal, Quebec, Canada; Centre for Interdisciplinary Research in Music Media and Technology (CIRMMT) - Montreal, Quebec, Canada; Richard King, McGill University - Montreal, Quebec, Canada; The Centre for Interdisciplinary Research in Music Media and Technology - Montreal, Quebec, Canada
Several successful spectral ear training software applications are now available and being used by individuals and audio institutions around the world. While some listener training applications address other audio attributes, they have not received the same level of development and refinement. A methodology, software application, and the required stimuli for a dynamic range controller ear training program are described herein. This program, based on ideas developed for spectral ear training, addresses several limitations of earlier dynamic range controller ear training programs. It has been designed for web access, making use of the Web Audio API for audio processing, a custom audio compressor design, and a wide range of musical stimuli.
Convention Paper 9888
P15-7 An “Infinite” Sustain Effect Designed for Live Guitar Performance—Mark Rau, Center for Computer Research in Music and Acoustics, Stanford University - Palo Alto, CA, USA; McGill University - Montreal, QC, Canada; Orchisama Das, Center for Computer Research in Music and Acoustics (CCRMA), Stanford University - Palo Alto, CA, USA
An audio effect to extend the sustain of a musical note in real-time is implemented on a fixed point, standalone processor. Onset detection is used to look for new musical notes, and once they decay to steady state the audio is looped indefinitely until a new note onset occurs. To properly loop the audio, pitch detection is performed to extract one period and the new output buffer is written in a phase aligned manner.
Convention Paper 9889