Download Emulating Rough and Growl Voice in Spectral Domain
This paper presents a new approach on transforming a modal voice into a rough or growl voice. The goal of such transformations is to be able to enhance voice expressiveness in singing voice productions. Both techniques work with spectral models and are based on adding sub-harmonics in frequency domain to the original input voice spectrum.
Download AIDE, A New Digital Audio Effects Development Environment
This paper describes a new rapid development environment for digital audio applications and computer instruments, AIDE (Audio Instrument Development Environment). The system is designed to help users build signal processing applications for use in music, multimedia and sound design. Based on a graphical patching principle, this system generates software using the V and Sound Object libraries. These provide the graphical interface/application framework and sound processing elements, respectively, for standalone programmes generated by AIDE. It is envisaged that the system will also generate application components in addition to stand-alone programs. The paper outlines in some detail the elements involved in the software. It discusses how the system is aimed at different types of users with different levels of interaction. The paper concludes with an overview of the typical application development cycle using the system.
Download ADAM - A 64 Channel General Purpose Real-Time Audio Signal Processor
In this paper we introduce a 64 channel audio processing unit made in our department. The audio processor uses a 16 bit control unit (Infineon XC 167) with ethernet interface running a realtime operating system and two Analog Devices ADSP-TS101S high performance tigerSHARC DSPs for audio stream processing. The first project implemented on this equipment is a 64 channel in, 32 channel out audio mixer with a sampling frequency of 48 kHz (leaving another 32 channels for effect feedback loops) or 96 kHz, alternatively. The audio processor is fully remote controllable via TCP/IP.
Download Non-Linear Digital Implementation of the Moog Ladder Filter
This paper presents a non-linear digital implementation of the Moog ladder filter. The implementation is relatively efficient and suitable for inclusion into real-time systems, for example virtual analog synthesizers. The analog circuit is analyzed to produce a differential equation. This equation is solved using Euler’s method, and the result is shown to be equivalent to a cascade of first order IIR sections with embedded non-linearities. Finally, the filter structure is modified to improve tuning.
Download A Fast Mellin Transform with Applications in DAFx
Many digital audio effects rely on transformations performed in the Fourier-transformed (frequency) domain. However, other transforms and domains exist and could be exploited. We propose to use the Mellin transform for a class of sound transformations. We present a fast implementation of the Mellin transform (more precisely a Fast Scale Transform), and we provide some examples on how it could be used in digital audio effects.
Download Transforming Singing Voice Expression - The Sweetness Effect
We propose a real-time system which is targeted to music production in the context of vocal recordings. The aim is to transform the singer’s voice characteristics in order to achieve a sweet sounding voice. It combines three different transformations namely SubHarmonic Component Reduction (reduction of sub-harmonics, which are found in voices with vocal disorders), Vocal Tract Excitation Modification (to achieve a change in loudness) and the Intonation Modification (to achieve smoother transitions in pitch). The transformations are done in the frequency domain based on an enhanced phase-locked vocoder. The Expression Adaptive Control estimates the amount of present vocal disorder in the singer’s voice. This estimate automatically controls the amount of SubHarmonic Component reduction to assure a natural sounding transformation.
Download Enhanced Time-Stretching Using Order-2 Sinusoidal Modeling
In this article, we introduce a 2-level sinusoidal model and demon strate its aptitude for a challenging digital audio effect: time-stretching without audible artifacts. More precisely, sinusoidal modeling is used at the two levels of the new sound model. We consider the frequency and amplitude parameters of the partials of the classic sinusoidal model as (control) signals, that we propose to model again using a sinusoidal model. This way, higher-level musical structures such as the vibrato and tremolo in the original sound are captured in the “partials of partials” of this order-2 sinusoidal model. We propose then a new time-stretching method, based on this new hierarchical model, which preserves not only the pitch of the original sound, but also its natural vibrato and tremolo.
Download An Efficient Phasiness Reduction Technique for Moderate Audio Time-Scale Modification
Phase vocoder approaches to time-scale modification of audio introduce a reverberant/phasy artifact into the time-scaled output due to a loss in phase coherence between short-time Fourier transform (STFT) bins. Recent improvements to the phase vocoder have reduced the presence of this artifact, however, it remains a problem. A method of time-scaling is presented that results in a further reduction in phasiness, for moderate time-scale factors, by taking advantage of some flexibility that exists in the choice of phase required so as to maintain horizontal phase coherence between related STFT bins. Furthermore, the approach leads to a reduction in computational load within the range of time-scaling factors for which phasiness is reduced.
Download A Piano Model Including Longitudinal String Vibrations
In this paper a mixed-paradigm piano model is presented. The major development is the ability of modeling longitudinal string vibrations. Longitudinal string motion is the reason for the metallic sound of low piano notes, therefore its modeling greatly improves the perceptual quality of synthesized piano sound. In this novel approach the transversal displacement of the string is computed by a finite-difference string model and the longitudinal motion is calculated by a set of second-order resonators, which are nonlinearly excited by the transversal vibration. The soundboard is modeled by a multi-rate filter based on measurements of real pianos. The piano model is able to produce high-quality piano sounds in real-time with about 5–10 note polyphony on an average personal computer.
Download The Feathered Clarinet Reed
In this research, a method previously In this research, a method previouslyapplied appliedtotoimprove improve a digital simulation of the avian syrinx is adapted to the geometry of the clarinet reed. The clarinet model is studied with particular attention to the case when the reed beats again the lay of the mouthpiece, closing off air flow to the bore once each period. In place of the standard reed table which gives steady-state volume flow as a function of constant pressure difference across the reed, a more realistic dynamic volume flow model is proposed. The differential equation governing volume flow dynamics is seen to have a singularity at the point of reed closure, where both the volume flow and reed channel area become zero. The feathered clarinet reed refers to the method, first used in the syrinx, to smooth or feather the volume flow cutoff in a closing valve. The feathered valve eliminates the singularity and reduces artifacts in the simulated clarinet output.