Download Acoustical Simulations of the Human Vocal Tract Using the 1D and 2D Digital Waveguide Software Model
This paper details software under development that uses the digital waveguide physical model to represent the sound creation mechanism and environment associated with the production of speech, specifically the human vocal tract. Focus is directed towards a comparison between the existing 1D waveguide method, on which several studies have already been conducted, and the developing 2D waveguide mesh method. The construction of the two models and the application of the tract geometry is examined, in addition, the inclusion of dynamic articulatory variations to increase the ability of such systems to create natural sounding speech is discussed. Results obtained from each suggest that the 2D model is capable of producing similarly accurate vowel spectra to that already accomplished with the 1D version, although speech-like sounds created with the 2D mesh appear to exhibit greater realism.
Download Room Impulse Response Shaping for Enhancement of Perceived Spaciousness and Auditory Distance
Room impulse response is one of most important information with localization of sound source in 3D audio. Actually we can adjust the distance and spaciousness of a sound source with impulse response of the room. Through consequent experiments, we found that C80 and EDT are varying systematically with sound source distances, and these variations are due to early reflection decay curves. This paper contains brief explanation of the two parameters as auditory distance cues, shaping of early reflection decay curves for control of auditory distance, and psychological test results of auditory distance control with early refection decay curve shaping. With these validations, we can confirm early reflection decay curve shape is effective factor for control of perceptual auditory distance and spaciousness in the room.
Download Semi-automatic Ambience Generation
Ambiances are background recordings used in audiovisual productions to make listeners feel they are in places like a pub or a farm. Accessing to commercially available atmosphere libraries is a convenient alternative to sending teams to record ambiances yet they limit the creation in different ways. First, they are already mixed, which reduces the flexibility to add, remove individual sounds or change its panning. Secondly, the number of ambient libraries is limited. We propose a semi-automatic system for ambiance generation. The system creates ambiances on demand given text queries by fetching relevant sounds from a large sound effect database and importing them into a sequencer multitrack project. Ambiances of diverse nature can be created easily. Several controls are provided to the users to refine the type of samples and the sound arrangement.
Download MATCONCAT: An Application for Exploring Concatenative Sound Synthesis Using MATLAB
The author has developed an application in MATLAB implementing concatenative sound synthesis (CSS) using feature matching. CSS is a process of combining short pieces of recorded sound to construct new sonic forms. Historically, CSS was developed for text-to-speech synthesis, but recently it has been explored as a musical sound synthesis method. The results have been called ‘musaics,’ the sonic analogue to mosaics made from small pieces of colored tile. Though this MATLAB application is less sophisticated than other audio mosaic algorithms, it is meant to be a free and open application for demonstrating and experimenting with the process. The author has used this application to create many interesting and entertaining sound examples. It has also been used to create several electroacoustic compositions. The application, and all of the sound examples presented here, can be downloaded for free from˜b.sturm.
Download Sonification of the Fission Model as an Event Generation System
I am proposing an event generation system for sonification purposes, where a simplified chain reaction model known as nuclear fission in physics is used. The basic background of the fission model, mapping of parameters as sonic entities and technical aspects of the realization procedure are presented.
Download Memory Reduction Technique of Spreading Function in MPEG AAC Encoder
In order to reduce the computational complexity of an MPEG AAC encoder, calculation of spreading function, which is the critical algorithm in the psychoacoustic model, can be replaced with look-up tables. However, the memory size of the table is considerably large in DSP or hardware implementation for portable devices. The paper deals with the methods to reduce the memory size. We modified a method originally used in an MP3 software encoder and adopted it in an MPEG AAC encoder. The result shows that only about one-third of the original size is required in programmable processor implementation such as DSP. Moreover, for hardware implementation, we analyzed the wordlength and reduced the size to only 3.6% compared to that for a 16-bit DSP while maintaining audio quality.
Download An MDCT-Based Psychoacoustic Model Co-Processor Design for MPEG-2/4 AAC Audio Encoder
The Psychoacoustic Model (PAM) is a very important role in MPEG-2/4 Advanced Audio Coding (AAC) encoding. It determines sound quality of a given encoder and influences a lot in computational complexity. This paper presents a new architecture design for MDCT-based PAM co-processor. This work is based on the dedicated hardware design which is different from traditional programmable approaches. Moreover, to reduce the complexity, we replace the calculations of spreading function with reduced fixed coefficients, and decrease the transform kernels from three to one unit.
Download Synthesis by Mathematical Models
Sound synthesis methods can be interpreted, from a mathe­ matical point of view, as a collection of techniques of selecting and conceptually organizing elements of a Hilbert space. In this sense, mathematics, being a highly structured and sophisticated system of classification, modeling and categorization, seems to be the natural tool to describe existing synthesis methods and to pro­ pose new ones. Because, from this perspective, one can think of any available (or theoretically predictable, or imaginable) synthe­ sis method as a collection of procedures to deal with meaningful parameters, with the term ”synthesis by mathematical models” we mean an extensive use of the modeling and categorization power of mathematics applied to the world of sounds. In this paper we give a few examples of sound synthesis tech­ niques, based on mathematical models. After reviewing shortly FM synthesis and synthesis by nonlinear distortion, and suggest­ ing some, to our advice, interesting open problems, we propose two different new methods: synthesis by means of elliptic func­ tions and synthesis by means of nowhere (or almost­nowhere) dif­ ferentiable functions and lacunary series. The resulting waveforms have been produced using CSound as an audio engine, driven by Python scripts.
Download Sound Texture Modeling and Time-Frequency LPC
This paper presents a method to model and synthesize the textures of sounds such as fire, footsteps and typewriters using time and frequency domain linear prediction coding (TFLPC). The common character of this class of sounds is that they have a background “din” and a foreground transient sequence. By using LPC filters in both the time and frequency domain and a statistical representation of the transient sequence, the perceptual quality of the sound textures can be largely preserved, and the model used to manipulate and extend the sounds.
Download Making Sound with Numbers, Six Years Later
In the first edition of the DAFx Conferences an extensive tutorial on professional and research software devoted to sound and music making was presented. The present paper attempts a revision of the concepts expressed in that tutorial, focusing particularly to the aspects related to research and innovation fostered by a strong paradigm shift that has happened in the mean time: that of Free Software development. Of course, this paradigm shift has also had its difficulties and harsh spots, requiring many extra efforts in order to overcome them. This paper will try to describe these as well as to outline the current state-of-the-art in the field.