Naotoshi Osaka

Sho-So-In: Control of a Physical Model of the Sho by Means of Automatic Feature Extraction from Real Sounds

This paper proposes a synthesis framework for sound hybridization that creates sho-like sounds with articulations that are the same as that of a given input signal. This approach has three components: acoustic feature extraction, physical parameter estimation, and waveform synthesis. During acoustic feature extraction, the amplitude and fundamental frequency of the input signal are extracted, and in the parameter estimation stage these values are converted to control parameters for the physical model. Then, using these control parameters, a sound waveform is calculated during the synthesis stage. Based on the proposed method, a mapping function between acoustical parameters and physical parameters was determined using recorded sho sounds. Then, sounds with various articulations were synthesized using several kinds of instrumental tones. As a result, sounds with natural frequency and amplitude variations such as vibrato and portamento were created. The proposed method was used in music composition and proved to be effective.

Timbre morphing and interpolation based on a sinusoidal model

There have been several attempts to synthesize the timbre in between two sounds. Several synthesis methods are reported to work well, but are not automatic throughout the whole process or are not precisely described if one wishes to trace the algorithm. An automatic algorithm of synthesizing morphed sounds and interpolated timbre has been reported. Two original sounds are analyzed using the M&Q algorithm. Correspondent partials of each sound are found using Dynamic Programming. Two synthesis methods are introduced using a sinusoidal model. One is to find correspondent partials within correspondent frames of two sounds. Then an interpolated partial of a new frame is calculated. Peak‐to‐peak match of sinusoidal parameters is done for a new frame and synthesized sounds are acquired. The other method is the one which changes the procedure sequence of the first method. Correspondence is considered for sequent partials and not a framewise signal. These two methods are compared with another simple synthesis meth...

The microsound synthesis framework in the lc computer music programming language

This article describes the design of a framework for sound synthesis in LC, a new computer music language we prototyped, together with concrete code examples. Unlike existing unit-generator languages, LC provides objects as well as library functions and methods that can directly represent microsounds and related manipulations that are involved in microsound synthesis. Furthermore, LC is equipped with traditional unit generators, and these two different abstractions can collaborate seamlessly. Although the framework for microsound synthesis itself is not particularly bound to the entire language design of LC, such seamless unification between the traditional concept of unit generators and LCs microsound synthesis framework contribute to making LCs programming model for microsound synthesis simpler and terser in comparison with existing unit-generator languages. These features of LCs entire sound-synthesis framework can help computer musicians to creatively explore the domain of microsound synthesis and would also be beneficial for further research in computer music language as a design exemplar.

Sound synthesis based on a new micro timbre notation

Timbre has become a major musical factor in contemporary and computer music. However, sufficient timbre theory has not yet been established. The author is challenging to create new timbre theory for music composition. The first step of its construction is to make the timbre descriptive. A micro timbre is defined, which is a perceptual impression of a sound with approximately 50 to 100‐ms duration, and describe sound as a micro timbre sequence. This can be used as a new notation system in place of common music notation. In dictation, micro timbre sequence and correspondent duration sequence are perceptually recorded. When synthesizing from this notation, sounds corresponding to the notation systems are either physically synthesized or searched for in a large sound database to generate sound data for a given duration. Two sequential sound data instances are first represented in sinusoidal representations and then are concatenated using a morphing technique. Sounds generated by a stream of water and similar ...

Multipitch estimation based on correlation between a harmonic structure model and an observed spectrum for mixed audio signals

In the research of sound source separation and resynthesis, multipitch estimation is an important topic. We propose a multipitch estimation technique for monaural audio signals. It introduces a method of calculating multiple pitches within a frame for a pitched sound signal. First, a harmonic structure is modeled for a pitch M (Hz), using the cases of odd integer multiples of M, even integer multiples of M, and odd integer multiples of M/2. Then correlations are derived between each of the harmonic structure models and an observed spectrum. Harmonic structure models are expressed as the summation of Gaussian functions in the frequency domain, where each harmonic has a peak at its center frequency. An evaluation function is dynamically defined to test how well arbitrary values of M fit the observed spectrum. The evaluation function is created by searching for weighted coefficients for the correlation values. Next, a number of maximal peaks equal to the number of sound sources are selected from the spectrum...

Measurements of reed vibration and pressure variation of the sho, the Japanese mouth organ

Measurements of reed vibration and pressure vibration of the sho were carried out. Reed displacement, sound pressure at both sides of the reed, and radiated sound pressure at the open end of the pipe were measured using an experimental sho model made from an acrylic pipe and a metal reed. The kashira, or cavity, was also made from an acrylic box, where the pipe is mounted so that the reed vibration can be measured by a laser displacement sensor. The measurement results show that reeds vibrate as a sinusoidal, and that, in contrast with earlier results obtained by experiments on harmonium reeds [J. P. Cottingham, C. J. Lilly, and C. H. Reed, 137th meeting of the ASA and the 2nd Convention of the EAA, pp. 14–19 (1999)], the amplitude of reed vibration increases with increasing blowing/drawing pressure. The sound pressure inside the tube shows peaks when the reed reaches its maximum displacement, and the sound pressure oscillates twice when the reed oscillates once. Further, sound pressure inside the kashira...