README.md

Forsynth

A small Fortran synthesizer to explore sound synthesis, sound effects, electronic music, algorithmic music, etc. Humbly follow the steps of Stockhausen, Kraftwerk and the Daft Punk!

But Forsynth could also be used for data sonification: https://fortran-lang.discourse.group/t/anecdotal-fortran/704/8 or to teach programming in a fun way!

Features

• By default, you have 8 stereo tracks. In fact 7 because the track 0 is used for the final mix. It takes 169 Mio in RAM for a two minutes duration. You can of course modify those parameters. Do you know The Beatles used 8 tracks the first time in August 1968 to record Hey Jude? The second song was Dear Prudence.
• Forsynth is a semi-analog studio: time is discretized (44100 samples/s) but the amplitude is coded as a Fortran real and digitized as a 16 bits signed integer only when generating the output WAV file.
• You need only a modern Fortran compiler and a media player, whatever your OS.
• GNU GPLv3 license.

Compilation and execution

You can easily build and run the project using the Fortran Package Manager fpm (https://github.com/fortran-lang/fpm) at the root of the project directory:

$ fpm build
$ fpm run

Or you can also use the build.sh script if you don't have fpm installed.

A WAV file was generated in the same directory, for example demo1.wav:

$ file demo1.wav
demo1.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz

You can then listen to your WAV using any media player, for example the SoX play command (or the ALSA command aplay):

$ play demo1.wav

demo1.wav:

 File Size: 21.2M     Bit Rate: 1.41M
  Encoding: Signed PCM
  Channels: 2 @ 16-bit
Samplerate: 44100Hz
Replaygain: off
  Duration: 00:02:00.00

In:2.32% 00:00:02.79 [00:01:57.21] Out:123k  [!=====|=====!] Hd:0.0 Clip:0

You can also use Audacity or Sonic Visualiser to visualise your music, either as a waveform or a spectrogram.

Contributing

• Post a message in the GitHub Issues tab to discuss the function you want to work on.
• Concerning coding conventions, follow the stdlib conventions: https://github.com/fortran-lang/stdlib/blob/master/STYLE_GUIDE.md
• When ready, make a Pull Request.

Technical information

Endianness

A WAV comprises a header with metadata then the soundtracks in PCM (https://en.wikipedia.org/wiki/Pulse-code_modulation), written in little endian. This program asserts your machine is little endian. If you are big endian, please use the -fconvert=big-endian flag with gfortran, or -convert big_endian with ifort. Or contribute to the code to allow an automatic detection of endianness.

• https://fortran-lang.discourse.group/t/writing-a-binary-file-in-little-endian/719/4
• https://en.wikipedia.org/wiki/Endianness

WAV / RIFF format

• https://en.wikipedia.org/wiki/Resource_Interchange_File_Format
• https://en.wikipedia.org/wiki/WAV
• http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html

Sound synthesis

• https://sites.google.com/site/learning4synthesizer/home
• https://en.wikipedia.org/wiki/Karplus%E2%80%93Strong_string_synthesis

Bibliography

English

• Jean-Claude Risset, Computer music: why ?, https://liberalarts.utexas.edu/france-ut/_files/pdf/resources/risset_2.pdf
• Dave Benson, Music - A Mathematical Offering, 2008, https://homepages.abdn.ac.uk/d.j.benson/pages/html/music.pdf.
• Jaffe, David A., and Julius O. Smith. “Extensions of the Karplus-Strong Plucked-String Algorithm.” Computer Music Journal 7, no. 2 (1983): 56. https://doi.org/10.2307/3680063.
• Karplus, Kevin, and Alex Strong. “Digital Synthesis of Plucked-String and Drum Timbres.” Computer Music Journal 7, no. 2 (1983): 43–55. https://doi.org/10.2307/3680062.
• Lähdevaara, Jarmo. Science of Electric Guitars and Guitar Electronics. Helsinki, Finland: Books On Demand, 2012.
• Deutsch, Diana. "The Paradox of Pitch Circularity"’. Acoustics Today 6, no. 3 (July 2010): 8–14. https://doi.org/10.1121/1.3488670.

French

• Vincent Magnin, "Format WAV : créez des ondes sonores en C", GNU/Linux Magazine n°190, février 2016, https://connect.ed-diamond.com/GNU-Linux-Magazine/GLMF-190/Format-WAV-creez-des-ondes-sonores-en-C
• Vincent Magnin, "Format WAV : des sons de plus en plus complexes", GNU/Linux Magazine n°190, février 2016, https://connect.ed-diamond.com/GNU-Linux-Magazine/GLMF-190/Format-WAV-des-sons-de-plus-en-plus-complexes
• Some sounds created with the C version of the program: http://magnin.plil.net/spip.php?article131
• Laurent de Wilde, Les fous du son - D'Edison à nous jours, Editions Grasset et Fasquelle, 560 pages, 2016, ISBN 9782246859277.
• Laurent Fichet, Les théories scientifiques de la musique aux XIXe et XXe siècles, Vrin, 1996, ISBN 978-2-7116-4284-7.
• Guillaume Kosmicki , Musiques électroniques - Des avant-gardes aux dance floors, Editions Le mot et le reste, 2nd edition, 2016, 416 p., ISBN 9782360541928.