This java applet demonstrates Fourier series, which is a method of expressing an arbitrary periodic function as a sum of cosine terms. In other words, Fourier series can be used to express a function in terms of the frequencies (harmonics) it is composed of.

Researchers at the MRC have developed a variety of bespoke software that facilitates the work that goes on in the centre, some of which is in the public domain. Notably there is a collection of Max MSP and puredata externals for dealing with ambisonics, and these algorithms are also available as VST and Audiounit plugins. The centre also produces commercial software including the MRC meter - a highly accurate audio metering plugin

Baudline is a scientific visualization tool that uses DSP for exploring the spectral domain. Explore, Analyze, and Discover.

Understanding Acoustic Feedback & Suppressors

CLAM (C++ Library for Audio and Music) is a full-fledged software framework for research and application development in the Audio and Music Domain. It offers a conceptual model as well as tools for the analysis, synthesis and processing of audio signals.

Mac OS X 10.6+, Intel chips only.

SoundMagic Spectral is a FREEWARE suite of 24 Audio Unit plug-ins that implement real-time spectral processing of sound. This groundbreaking set of effects give you unprecedented control and creativity in the processing of audio, whether from static audio files or live audio streams. SoundMagic Spectral builds on the work of the OS 9 software known as SoundMagic DSP, and takes it to even more exotic sonic realms.

WebPd aims to allow a subset of Pure Data audio patches to run in the browser without plugins. Right now the focus is on DSP objects, to enable you to mock up audio engines in Pd, put them on the web, and control them with Javascript.

MIRtoolbox offers an integrated set of functions written in Matlab, dedicated to the extraction from audio files of musical features such as tonality, rhythm, structures, etc. The objective is to offer an overview of computational approaches in the area of Music Information Retrieval. The design is based on a modular framework: the different algorithms are decomposed into stages, formalized using a minimal set of elementary mechanisms. These building blocks form the basic vocabulary of the toolbox, which can then be freely articulated in new original ways.

pdf

MATLAB code examples used in book can be downloaded here.

Assistant Professor of Music
I am Associate Profesor at the Tulane Univeristy Music Department and Director of the Music Science and Technology Program

My current concentration is in electroacoustic, computer music, research topics in computer music and acoustic music. I am the author of the World Scientific Publishing book, "Introduction to Digital Signal Processing."

pyo is a Python module written in C to help digital signal processing script creation.

pyo is a Python module containing classes for a wide variety of audio signal processing types. With pyo, user will be able to include signal processing chains directly in Python scripts or projects, and to manipulate them in real time through the interpreter. Tools in pyo module offer primitives, like mathematical operations on audio signal, basic signal processing (filters, delays, synthesis generators, etc.), but also complex algorithms to create sound granulation and others creative audio manipulations. pyo supports OSC protocol (Open Sound Control), to ease communications between softwares, and MIDI protocol, for generating sound events and controlling process parameters. pyo allows creation of sophisticated signal processing chains with all the benefits of a mature, and wildly used, general programming language.

Everyone has their favorite computing platform, regardless if it is Matlab, Octave, Scilab, Mathematica, Mathcad, etc.  I have been using Python and the common numerical and scientific packages available.  Personally, I have found this to be very useful in my work.  Lately there has been some chatter on speeding up Python.

I have just learned that Sophocles J. Orfanidis, the well-known professor with the ECE Department of Rutgers University, has made two of his signal processing textbooks available for downloading on the Internet.

This book was previously published by Pearson Education, Inc. Copyright (c) 1996--2009 by Prentice Hall, Inc. Previous ISBN 0-13-209172-0.
The book's copyrights were transferred from Prentice Hall to Sophocles J. Orfanidis in 2009. A new version of the book, that includes corrections of all the typos, is now freely available in PDF format, and in a 2-up form. A solutions manual is also available.

There are so many different time- and frequency-domain methods for generating complex baseband and analytic bandpass signals that I had trouble keeping those techniques straight in my mind. Thus, for my own benefit, I created a kind of reference table showing those methods. I present that table for your viewing pleasure in this blog.

The Music Technology Group (MTG) of the Universitat Pompeu Fabra in Barcelona, part of its Department of Information and Communication Technologies, is specialized in sound and music computing. With more than 40 researchers coming from different and complementary disciplines, the MTG carries out research on topics such as audio signal processing, sound and music description, musical interfaces, sound and music communities, and performance modeling. The MTG combines basic engineering strengths in Signal Processing, Machine Learning and Human Computer Interaction with multidisciplinary methodologies coming from other fields.

Audio signal processing tutorials & software
Bernsee
Stephan M. Bernsee

The DSP Dimension started out as a platform for online courses and tutorials on Digital Signal Processing in 1999 as part of Stephan Bernsee’s lectures on advanced audio DSP held at various institutions around Germany. The DSP Dimension quickly became a standard resource for specialized DSP topics like time stretching and pitch shifting and is part of engineering classes at several universities across Europe as well as a frequently featured content in many popular magazines. Today Stephan and his team are providing consulting and development services to the audio signal processing market and are developing applications marketed through their partners around the world.

Arbeitsgruppe Multimedia and Security

Leiterin der Arbeitsgruppe:

Prof. Dr.-Ing. Jana Dittmann

Fakultät für Informatik
Advanced Multimedia and Security
Institut für Technische und Betriebliche Informationssysteme
Otto-von-Guericke-Universität Magdeburg

Professional Time Stretching and Pitch Shifting Solution
for Desktop and Mobile Platforms

Real-time audio programming 101: time waits for nothing

Ongoing development of a Free, Open Source bio-sensing software/hardware framework for the application of muscle sounds to biophysical generation and control of music, video and responsive milieux.

FAUST is a high-level programming language for digital signal processing, with special support for real-time audio applications and plugins on various software platforms including Linux, Mac-OS-X, iOS, Windows, and embedded computing environments. Audio plugin formats supported include VST, LADSPA, Pd, Max/MSP, SuperCollider, and more. This tutorial provides an introduction focusing on a simple example of white noise filtered by a variable resonator.

Julius Orion Smith III
Home Page

This is my blog from the point of view of a music/audio DSP research engineer / educator. It is informal and largely nontechnical because nearly everything I have to say about signal processing is (or will be) somewhere in my four-book series: Mathematics of DFT with Audio Applications, Introduction to Digital Filters, Physical Audio Signal Processing and Spectral Audio Signal Processing

Boolean logic in the server

PyAudio

PyAudio provides Python bindings for PortAudio, the cross-platform audio I/O library. With PyAudio, you can easily use Python to play and record audio on a variety of platforms.

PyAudio is designed to work with the PortAudio v19 API 2.0. Note that PyAudio currently only supports blocking-mode audio I/O.

PyAudio is still super-duper alpha quality. It has run on GNU/Linux 2.6, Microsoft Windows 7/XP, and Apple Mac OS X 10.5+—but it could use more testing.

PyAudio is inspired by:

pyPortAudio/fastaudio: Python bindings for PortAudio v18 API.
tkSnack: cross-platform sound toolkit for Tcl/Tk and Python.

Sonic Visualiser is an application for viewing and analysing the contents of music audio files.
The aim of Sonic Visualiser is to be the first program you reach for when want to study a musical recording rather than simply listen to it.

We hope Sonic Visualiser will be of particular interest to musicologists, archivists, signal-processing researchers and anyone else looking for a friendly way to take a look at what lies inside the audio file.

Sonifyer is a stand-alone application for data sonification (and visualization). The software allows you to choose between, or to combine, two sonification methods: 1. audification or 2. parameter mapping (based on FM synthesis)

This section contains a collection of resources for experts and novices to the field

The andraudio mailing list is a community discussion list for application and middleware developers working with audio on Android (whether for music apps, games, media or whatever else you can imagine). The topic here is Android audio development. That means development using Android's Java audio API, native C/C++ bridged to Java, and Android's implementation of OpenSL ES. We're also interested in discussing Android audio platform internals. We are here to discuss ideas and to help each other. Everyone is welcome. Please feel free to introduce yourself.

The NUGEN Audio product range conforms to the VST and Audio Unit standards, available for both Mac OSX and PC Windows operating systems.

"Paul" on coreaudio mailing list

Rubber Band Library is a high quality software library for audio time-stretching and pitch-shifting. It permits you to change the tempo and pitch of an audio stream or recording dynamically and independently of one another.

The Operation of the Phase Vocoder
A non-mathematical introduction to the Fast Fourier
Transform

CDP: The Composers' Desktop Project
Based in the UK, CDP is an international network of composers and programmers guided by a vision of amazing sonic possibilities and how they can be woven into the fabric of music. We have been working together since 1986.

DNA Direct Note Access is a technology that makes the impossible possible: for the first time in audio recording history you can identify and edit individual notes within polyphonic audio material. The unique access that Melodyne affords to pitch, timing, note lengths and other parameters of melodic notes will now also be afforded to individual notes within chords.

Cool Stuff Labs is currently specializing in the field of Audio Signal Processing, with a particular focus on plug-in development for DAWs (Digital Audio Workstations). We are fully licensed Digidesign Development Partners, and can provide contract services to third parties interested in development for Pro Tools or any other platform.

terminatorX is a realtime audio synthesizer that allows you to "scratch" on digitally sampled audio data (*.wav, *.au, *.ogg, *.mp3, etc.) the way hiphop-DJs scratch on vinyl records.

Sonic Visualiser is an application for viewing and analysing the contents of music audio files.

S P E A R

Sinusoidal Partial Editing Analysis and Resynthesis

The Meta Studio is a polyrhythmic sequencing and synthesis application for Pure Data. It uses graph-on-parent objects to implement a modular system of sequencing, synthesis and effects with a flexible patching system.

You can download it here: metastudio-0.3-11b.zip.

Designing Sound teaches students and professional sound designers to understand and create sound effects starting from nothing. Its thesis is that any sound can be generated from first principles, guided by analysis and synthesis. The text takes a practitioner's perspective, exploring the basic principles of making ordinary, everyday sounds using an easily accessed free software. Readers use the Pure Data (Pd) language to construct sound objects, which are more flexible and useful than recordings.

Solutions Manual
A solutions manual is available to instructors. Please contact us to obtain a copy.

Teaching Material
This book originated as a set of notes for a third-year signal processing class at EPFL, and was refined over several years of teaching; its contents have been tuned to fit a schedule of about 25 2-hour classes. We are working on a set of PowerPoint slides displaying the fundamental concepts and the key figures in the book which can be used as classroom teaching material. Please contact us if you are interested in obtaining a copy.

by Paolo Prandoni and Martin Vetterli

With a novel, less formal approach to the subject, the authors have written a book with the conviction that signal processing should be taught to be fun. The treatment is less focused on the mathematics and more on the conceptual and practical aspects but the book remains an engineering text, with the goal of helping students solve real-world problems. In this vein, the last chapter pulls together all the topics discussed throughout the book into an in-depth look at the development of an end-to-end communication system, namely, a modem for communicating digital information over an analog channel.

Richard (Rick) Lyons is a consulting Systems Engineer and lecturer with Besser Associates in Mountain View, California.

Music DSP Frequently Asked Questions

QuteCsound is a frontend for Csound featuring a highlighting editor with autocomplete, interactive widgets and integrated help. It is a cross-platform and aims to be a simple yet powerful and complete development environment for Csound. It can open files created by MacCsound.

Cookbook formulae for audio EQ biquad filter coefficients
by Robert Bristow-Johnson

Mega Nerd Pty Ltd offers electronic design, software development and educational services

jack_oscrolloscope is a simple waveform viewer for JACK. The waveform is displayed in realtime, so you can always see the signal the instant it comes through JACK's input port.

pyliblo is a Python wrapper for the liblo OSC library. It supports almost the complete functionality of liblo, allowing you to send and receive OSC messages using a nice and simple Python API.

Also included are the command line utilities send_osc and dump_osc.

liblo is an implementation of the Open Sound Control protocol for POSIX systems, started by Steve Harris and now maintained by Stephen Sinclair.

a team of Professional Audio Engineers and Programmers/Musicians dedicated to providing digital audio plugins with unsurpassed sonic integrity for Studios and Musicians worldwide.

PXDK is a GUI cross-platform development kit, designed specifically for audio plug-ins. It is the perfect tool for making stable, professional plug-ins for multiple targets, without sacrificing any advanced features.
PXDK is an object-oriented system, using C++. Yes, this means you can produce Cocoa plug-ins on 64-bit OSX, without even reading 1 single line of Obj-C. This is the power of PXDK. Instead of using your energy on ever-changing APIs, you can focus on the value which the end-user can appreciate.

PXDK is available for VST 2.4, VST 3, AU, RTAS and TDM, Windows and OSX, 32- and 64-bit, Carbon and Cocoa. And for every single one of those platforms, your code is the same (although, for TDM you would obviously need to write extra DSP code).

PhonoXone Software, founded by Sonic Timeworks co-founder, Michael Olsen. Michael has worked in the audio software industry for more than 10 years, providing his extensive software development knowledge to various commercial software firms.
Michael's deep interest in cross-platform development has resulted in the cross-platform GUI and Utility library, named PXDK

PhonoXone is located in Denmark, on the western coast of Zealand.

JAMin is the JACK Audio Connection Kit (JACK) Audio Mastering interface. JAMin is an open source application designed to perform professional audio mastering of stereo input streams. It uses LADSPA for digital signal processing (DSP). JAMin is licensed under the GPL.

This book is a gentle introduction to digital filters, including mathematical theory, illustrative examples, some audio applications, and useful software starting points. The theory treatment begins at the high-school level, and covers fundamental concepts in linear systems theory and digital filter analysis. Various "small" digital filters are analyzed as examples, particularly those commonly used in audio applications. Matlab programming examples are emphasized for illustrating the use and development of digital filters in practice.

This book was written for my introductory course in digital audio signal processing, which I have given at the Center for Computer Research in Music and Acoustics (CCRMA) since 1984. The course was created primarily as a first course in digital signal processing for entering Music Ph.D. students in the Computer Based Music Theory and Acoustics program. Due to the nature of CCRMA research, this book will emphasize audio and music applications, although the material on the subject of digital filters itself is not specific to audio or music.

Vamp is an audio processing plugin system for plugins that extract descriptive information from audio data — typically referred to as audio analysis plugins or audio feature extraction plugins.

FAUST is a compiled language for real-time audio signal processing.
The name FAUST stands for Functional AUdio STream. Its programming model combines two approaches : functional programming and block diagram composition. You can think of FAUST as a structured block diagram language with a textual syntax.

Synth Secrets
For your enjoyment, we've collected together links to this hugely popular SOUND ON SOUND series, written by synth afficionado and regular contributor Gordon Reid.

ref: Claire Carton

Impromptu