Download The Origins of DAFx and its Future within the Sound and Music Computing Field DAFX is an established conference that has become a reference gathering for the researchers working on audio signal processing. In this presentation I will go back ten years to the beginning of this conference and to the ideas that promoted it. Then I will jump to the present, to the current context of our research field, different from the one ten years ago, and I will make some personal reflections on the current situation and the challenges that we are encountering.
Download Soliton Sonification - Experiments with the Kortweg-deVries Equation Solitons are special solutions of certain nonlinear partial differential equations of mathematical physics. They exhibit properties that are partly similar to the solutions of the linear wave equation and partly similar to the behaviour of colliding particles. Their characteristic features are well-known in the mathematical literature but few closed-form solutions are available. This contribution derives algorithmic structures for the computation of solitons in a dimensionless space-time domain which can be scaled to the audio frequency range. The investigations are confined to first and second order solutions of the Korteweg-de Vries equation. Sound examples show that the effects of wave propagation and soliton interaction can be represented by audible events.
Download Digital Grey Box Model of the Uni-Vibe Effects Pedal This paper presents a digital grey box model of a late 1960s era Shin-ei Uni-Vibe(r) 1 analog effects foot pedal. As an early phase shifter, it achieved wide success in popular music as a unique musical effect, noteworthy for its pulsating and throbbing modulation sounds. The Uni-Vibe is an early series all-pass phaser effect, where each first-order section is a discrete component phase splitter (no operational amplifiers). The dynamic sweeping movement of the effect arises from a single LFO-driven incandescent lamp opto-coupled to the light dependent resistors (LDRs) of each stage. The proposed method combines digital circuit models with measured LDR characteristics for the four phase shift stages of an original Uni-Vibe unit, resulting in an efficient emulation that preserves the character of the Uni-Vibe. In modeling this iconic effect, we also aim to offer some historical and technical insight into the exact nature of its unique sound.
Download VowSynth: A Synthesizer of Vowel Sounds Based on Additive Synthesis This article presents the design and implementation of a non real-time voice synthesizer based on the analysis of a soprano voice singing the five spanish vowels. The analysis is based on the SMS technique and the synthesis uses additive synthesis.
Download Audio-Tactile Glove This paper introduces the Audio-Tactile Glove, an experimental tool for the analysis of vibrotactile feedback in instrument design. Vibrotactile feedback provides essential information in the operation of acoustic instruments. The Audio-Tactile Glove is designed as a research tool for the investigation of the various techniques used to apply this theory to digital interfaces. The user receives vibrations via actuators distributed throughout the glove, located so as not to interrupt the physical contact required between user and interface. Using this actuator array, researchers will be able to independently apply vibrotactile information to six stimulation points across each hand exploiting the broad frequency range of the device, with specific sensitivity within the haptic frequency range of the hand. It is proposed that researchers considering the inclusion of vibrotactile feedback in existing devices can utilize this device without altering their initial designs.
Download Using Semantic Differential Scales To Assess The Subjective Perception Of Auditory Warning Signals The relationship between physical acoustic parameters and the subjective responses they evoke is important to assess in audio alarm design. While the perception of urgency has been thoroughly investigated, the perception of other variables such as pleasantness, negativeness and irritability has not. To characterize the psychological correlates of variables such as frequency, speed, rhythm and onset, twenty-six participants evaluated fifty-four audio warning signals according to six different semantic differential scales. Regression analysis showed that speed predicted mostly the perception of urgency, preoccupation and negativity; frequency predicted the perception of pleasantness and irritability; and rhythm affected the perception of urgency. No correlation was found with onset and offset times. These findings are important to human-centred design recommendations for auditory warning signals.
Download A simple, accurate wall loss filter for acoustic tubes This research presents a uniform approximation to the formulas of Benade and Keefe for the propagation constant of a cylindrical tube, valid for all tube radii and frequencies in the audio range. Based on this approximation, a simple expression is presented for a filter which closely matches the thermoviscous loss filter of a tube of specified length and radius at a given sampling rate. The form of this filter and the simplicity of coefficient calculation make it particularly suitable for real-time music applications where it may be desirable to have tube parameters such as length and radius vary during performance.
Download Trajectory Anti-aliasing on Guaranteed-passive Simulation of Nonlinear Physical Systems This article is concerned with the accurate simulation of passive nonlinear dynamical systems with a particular attention paid on aliasing reduction in the pass-band. The approach is based on the combination of Port-Hamiltonian Systems, continuous-time statespace trajectories reconstruction and exact continuous-time antialiasing filter realization. The proposed framework is applied on a nonlinear LC oscillator circuit to study the effectiveness of the method.
Download 2-D digital waveguide mesh topologies in room acoustics modelling Digital waveguide mesh models have provided an accurate and efficient method of modelling the properties of many resonant structures, including acoustic spaces. 2-D rectilinear and triangular mesh structures have been used extensively in the past to model plates and membranes and are presented here as potential analogues to 2-D acoustic spaces. Impulse response measurements are taken and comparisons are made regarding the spectral content and the associated properties when compared with standard room acoustic parameters. Enhanced mesh structures are examined using frequency warping techniques and high-resolution sampling rates. The 2-D triangular mesh is shown to be considerably superior to the rectilinear mesh in terms of the measurements taken, with a further significant improvement being made by using the same mesh oversampled to a much higher resolution to improve the bandwidth of the measured impulse responses.
Download Wave Digital Filter Adaptors for Arbitrary Topologies and Multiport Linear Elements We present a Modified-Nodal-Analysis-derived method for developing Wave Digital Filter (WDF) adaptors corresponding to complicated (non-series/parallel) topologies that may include multiport linear elements (e.g. controlled sources and transformers). A second method resolves noncomputable (non-tree-like) arrangements of series/parallel adaptors. As with the familiar 3-port series and parallel adaptors, one port of each derived adaptor may be rendered reflection-free, making it acceptable for inclusion in a standard WDF tree. With these techniques, the class of acceptable reference circuits for WDF modeling is greatly expanded. This is demonstrated by case studies on circuits which were previously intractable with WDF methods: the Bassman tone stack and Tube Screamer tone/volume stage.