Sound-Playing-HOWTO

  The Linux Sound Playing HOWTO
  Yoo C. Chung, [e-mail]
  v1.6, 11 August 1998

  This document lists applications for Linux that play various sound
  formats.


  1.  Introduction

  This is the Sound Playing HOWTO.  It lists the many sound formats and
  the applications that can be used to play them.  It also lists some
  hacks and advice on using these applications.  There are also some
  other interesting applications related to sound not directly related
  to playback.  However, this document does not describe how one can
  setup a Linux system for sound support.  Refer to the Linux Sound
  HOWTO by Jeff Tranter for instructions on setting up a Linux system
  for sound support and the supported sound hardware.

  This deals with normal user sound applications.  That is, it is only
  concerned about what the average user needs to know on the application
  side of sound, not exotic stuff like speech synthesis, or hardware
  stuff which is dealt in the Sound HOWTO.



  1.1.  Copyright of this document

  This document can be freely distributed and modified (I would
  appreciate it if I were notified of any modifications), as long as
  this copyright notice is preserved.  However, it cannot be placed
  under any further restrictions, and a modified document must have the
  same copyright as this one.  Also, credit must be given where due.



  1.2.  Copyright of the listed applications

  If there is no mention of any copyright, then the application is under
  the GNU General Public License.



  1.3.  Where to get this document

  The most recent official version of this document can be obtained from
  the Linux Documentation Project <  The
  most recent unofficial version of this document can be obtained from
  <~wacko/howto/>.

  A Korean version of this document (very outdated) is available at
  <~wacko/howto/Sound-Playing-HOWTO.ks>.

  A Japanese version of this document is available at
  <



  1.4.  Feedback

  I am not omniscient, and I don't use all the applications in here (a
  few I can't even try), so there are bound to be mistakes.  Also,
  programs usually continuously evolve, so documentation tends to get
  out of date.  Therefore, if you find anything wrong, please send me
  any corrections.  Suggestions or additions to this document are
  welcome, too.
  1.5.  Acknowledgments

  All the authors of the applications in this HOWTO.  Also, Hannu
  Savolainen for the great sound driver and Linus Torvalds for the great
  underlying OS.

  I'd also like to thank Raymond Nijssen ([e-mail]), Jeroen
  Rutten ([e-mail]), Antonio Perez ([e-mail]), Ian
  Jackson ([e-mail]), and Peter Amstutz
  ([e-mail]) for their information and help.



  2.  Playing Various Sound Formats

  There are many kinds of sound formats (WAV, MIDI, MPEG etc.).  Below,
  we list the various formats and the applications that can be used to
  play them.



  2.1.  MIDI

  MIDI stands for Musical Instrument Device Interface.  MIDI files
  usually have the extension .mid.  They contain sequencing information,
  that is, information on when to play what instrument in what way, etc.
  Depending on your hardware (and maybe the software you use to play
  them), the sound might be awesome, or it might be downright crappy.



  2.1.1.  adagio

  This package includes mp (a command-line MIDI file player) and xmp (an
  XView based MIDI file player, not to be confused with the module
  player also called xmp).  You will need the SlingShot extensions to
  use xmp.  It also contains other programs for playing Adagio scores.


  If you have a GUS, mp can also play MOD files (see section ``Modules''
  for more information on modules).

  One little annoying bug (as of version 0.5 on some hardware) is that
  the sound breaks at the end.  Namely, instead of ending the sound the
  way the MIDI file specifies, it ends by playing the note right before
  the last one in a long interval.  It hasn't stopped me from using mp,
  but it might prevent someone from using it for `real' work.  It also
  starts up relatively slowly.

  The package does not mention any copyright (at least none that I can
  find), so I assume it can be freely redistributed and modified.  (By a
  strict interpretation of copyright law, nothing gives one the right to
  do these things, but I somehow doubt that this was the intention of
  the author.)

  It is a port of the CMU MIDI Toolkit to Linux (though there was enough
  added to make this questionable) by Greg Lee
  ([e-mail]).

  It can be obtained from
  .  The
  binaries included here are in a.out format (linked with ancient
  libraries), and the xmp binary segfaults in a X11R6 environment
  (XFree86 3.1.1, libc 4.7.2).  The mp binary works fine in an a.out
  environment.

  You will need a bit of hackery to compile it.  Actually, it's not much
  of a hackery.  All you have to do is to include the -lfl switch at the
  end of SHROBJ and XMPOBJ in the Makefile.  This is to link in the flex
  library, which is not linked in by default.  Then follow the
  installation instructions.  And don't forget to have XView and the
  SlingShot extensions installed if you want to compile xmp.



  2.1.2.  TiMidity

  Some people recommend this experimental program because of good sound
  quality (which is very true, it's much better than mp on a Sound
  Blaster 16, though it probably won't be much different on soundcards
  with wavetable synthesis like the GUS).  However, it suffers from high
  CPU loads.  It plays MIDI by first converting MIDI to WAV and then
  plays the WAV (you can also convert a MIDI file to a WAV file without
  playing if you want).  This is the reason for its CPU intensive
  nature.

  It also has an optional ncurses, SLang, Tcl/Tk or Motif interface.

  You need Gravis Ultrasound patch files to use this.  Look into the FAQ
  included with TiMidity for more information.

  The author is Tuukka Toivonen ([e-mail]).

  The latest version of TiMidity can be found at the TiMidity home page
  <~tt/timidity/>.  This page also contains a link to
  a small library of GUS patches.



  2.1.3.  playmidi

  This is a MIDI player that plays to FM, GUS, and external MIDI.  It is
  supposed to have a faster startup time compared to other MIDI players.
  It is also able to play Creative Music Files, Microsoft RIFF files,
  and large MIDI archives from games such as Ultima 7.

  It has an X interface and a SVGA interface.  It also has an option for
  real time playback with tracking all the notes on each channel and the
  current playback clock (included automatically with xplaymidi and
  splaymidi).

  You should do something like



       $ splaymidi foo.mid; stty sane



  if you are going to use the SVGA interface, since it doesn't reset the
  terminal tty mode properly.  The SVGA interface may be removed in the
  near future.

  It was written by Nathan Laredo ([e-mail] or
  [e-mail]).

  It can be obtained from
  .


  2.2.  Modules

  Modules (in computer music) are digital music files, made up of a set
  of samples and sequencing information, telling the player when to play
  which sample (instrument) on which track at what pitch, optionally
  performing an effect, like vibrato for example.

  An advantage it has over MIDI is that it can include almost any kind
  of sound (including human voices).  Another is that it sounds just
  about the same on any platform, because the samples are in the module.
  A disadvantage it has is that it has a much larger file size compared
  to MIDI.  Another one is that it has no real standard format (the only
  `real' one is the ProTracker, which many modules aren't quite
  compatible with).  It originated on the Amiga.

  The most common format has the extension .mod.  There are many other
  extensions depending on what format they are in.



  2.2.1.  tracker

  This very portable program (it has been ported to many platforms)
  plays Soundtracker and Protracker music modules.  It uses 16 bit
  stereo output, and I consider the quality to be very good.  If you
  need a simple way to reduce CPU load use the -mono option.

  This is a giftware program (quoting the author).  It is by Marc Espie
  ([e-mail]).

  A version of this with the Makefile already tweaked for Linux can be
  obtained from
  .



  2.2.2.  gmod

  This is a music module player for the Gravis Ultrasound card.  4/6/8
  channel MOD, 8 channel 669, MultiTracker (MTM), UltraTracker (ULT),
  FastTracker (XM), and ScreamTracker III (S3M) are the supported
  formats.

  It requires a version 3.0 or later sound driver.  And a GUS, of
  course.  You may need to modify the kernel to make volume control work
  the way you want.

  This has an X interface.  It uses the QT toolkit (needs version 0.99
  or greater).  Check the QT toolkit homepage < for
  information on QT.

  This can be freely distributed.  It was originally written by Hannu
  Savolainen, and now maintained by Andrew J. Robinson
  ([e-mail]).

  It can be obtained from
  .



  2.2.3.  MikMod

  This portable module player plays XM, ULT, STM, S3M, MTM, MOD and UNI
  formats.  (The UNI format is an internal format used by MikMod.)  It
  has support for zipped module files.  It uses 16 bit stereo for the
  sound output.  Use the -m option (for mono output) if you need a
  simple way to lower the CPU load.

  The Unix version can either use ncurses or Tcl/Tk for its interface.
  It can also be used as a library, not just an independent program.

  It was originally written by Jean-Paul Mikkers ([e-mail]).  It is
  now maintained by Jake Stine ([e-mail]).  This is shareware
  that has to be registered if you want to use it commercially.  You
  also need permission to redistribute it commercially (non-commercial
  redistribution does not need such permission).

  This can be found at the MikMod home page
  <~amstpi/mikmod.html>.



  2.2.4.  xmp

  This is a module player (not to be confused with Adagio's xmp) which
  can play MOD, S3M, MTM, PTM, PTR, STM, 669, and XM modules (other
  formats are also supported, but still experimental or incomplete).  If
  you have soundcards with wavetable synthesis (GUS or SoundBlaster
  32AWE), then you can use this feature of the soundcard to lower the
  load on the CPU.  It also supports compressed modules.

  An X frontend to xmp is also available.

  This was written by Claudio Matsuoka ([e-mail]) and
  Hipolito Carraro Jr.

  This can found at the xmp home page <



  2.2.5.  s3mod

  This plays 4/6/8 track MOD modules and Scream Tracker 3 modules.  It
  uses 8 bit mono output with a sampling rate of 22000 Hz by default.
  You can use the option -s to enable stereo, -b to enable 16 bit
  output, and -f to set the sampling frequency.  However, the sound
  output is worse than tracker (some noise), so I recommend using
  tracker instead of s3mod for playing ordinary MOD files (unless you
  have an underpowered machine).  It has a much smaller CPU load
  compared to tracker.

  It is copyrighted by Daniel Marks and David Jeske ([e-mail]),
  but you can do anything you want with it (except that you can't claim
  you wrote it).

  It can be obtained from
    v1.09.tar.gz>.



  2.2.6.  mod

  This beta program plays MODs (15/31-instrument, up to 32 voices),
  MTMs, ULTs and S3Ms on the Gravis Ultrasound card.  It can also use
  packed modules if you have gzip, lharc, unzip, and unarj installed.
  It cannot play Powerpacked modules or modules packed with some Amiga
  composers ("PACK" signature).

  This requires at least version 3.0 of the sound driver.  It won't work
  with the 2.90-2 or earlier version of the sound driver.  The text
  interface requires ncurses.  There is also an X interface included,
  which uses Tcl/Tk.

  It was written by Mikael Nordqvist ([e-mail] or
  [e-mail]).

  It can be obtained from
  .



  2.2.7.  nspmod

  This is an alpha module player which can play MTM, S3M, and MOD
  modules.  It is intended to be a module player for soundcards without
  a DSP (not to be confused with what Creative Labs calls a DSP).  It
  has a CPU load somewhat similar compared to tracker.


  It has a feature which lets modules loop if they want to.  The number
  of loops can be limited by the -l option.  It uses only 8 bit sound
  output (as of version 0.1).

  This was written by Toru Egashira ([e-mail]).

  It can be obtained from
  .



  2.2.8.  yampmod

  This alpha program was designed to play 4-channel modules using the
  minimum of CPU resources.  It was not designed to produce high quality
  sound.  So the only sound output it produces is 22 kHz mono output.
  Also, the output isn't as clean as it should be, reflecting its alpha
  status.

  It was written by David Groves ([e-mail]).

  It can be obtained from
  .



  2.3.  MPEG audio streams

  MPEG is a standard specifying the coding of video and the associated
  audio for digital storage.  MPEG is usually associated with video, but
  the audio part of the standard can be used separately.  The audio part
  of the MPEG standard defines three layers, layer I, II, and III.
  Players that can decode higher layers can also decode lower layers
  (e.g. layer III players can play layer II files).  Layer I MPEG audio
  files usually have the extension .mpg (so if there is a file with this
  extension that can't be played by a MPEG video player, it's probably
  an audio stream), layer II usually have the extension .mp2, and layer
  III usually have the extension .mp3.  The audio compression is pretty
  good.  A two megabyte layer II MPEG audio file will probably take up
  25 megabytes for a raw PCM sample file with the same quality.



  2.3.1.  mpg123

  This beta program is an efficient MPEG audio stream player, which has
  support for layers I, II, and III.  It is based on code from many
  sources.  It is able to play in real time streams that are read by
  HTTP (i.e. one can play an MPEG audio stream directly over the World
  Wide Web).

  The main author is Michael Hipp ([e-mail]-
  tuebingen.de).  It may be used and distributed in unmodified form
  freely for non-commercial purposes.  Inclusion in a collection of free
  software (such as CD-ROM images of FTP servers) is explicitly allowed.

  The latest version can be obtained from the mpg123 homepage
  <



  2.3.2.  maplay 1.2

  This MPEG audio stream player only has support for layer I and layer
  II streams, and lacks support for layer III streams.  It supports 16
  bit sound cards on Linux.

  It is pretty CPU intensive, taking up to about 55% CPU time on a 60MHz
  Pentium.  The output is intolerable on a 66MHz 486 because the CPU
  just can't catch up with the sound.  If this happens to you, try
  playing only one side of the audio stream (with the -l or -r option),
  instead of the default stereo.

  A slight change in one of the files may be necessary in order to
  compile it.  Namely, you may need to add the following line to the
  beginning of the file configuration.sh.



       #! /bin/sh



  The author is Tobias Bading ([e-mail]).  maplay 1.2 can
  be obtained from    berlin.de/pub/misc/maplay1.2/maplay1_2.tar>.



  2.3.3.  maplay 1.3b

  This is an unofficial modification (i.e. not by the original author)
  of maplay 1.2, so that it can run with a much lower load on the CPU.
  It accomplishes this mainly by making u-law output actually work on
  other platforms besides the SPARC.  Note that it uses u-law output by
  default, so the sound quality is lower.

  The modifications were made by Orlando Andico
  ([e-mail]).

  This can be obtained from
    Linux.tar.gz>.



  2.3.4.  maplay3

  This is another derivative of maplay 1.2.  It adds support for MPEG
  Layer 3 audio streams.  Currently it seems to have some bugs in its
  playback (you may hear some screeching noises).  You may have to
  twiddle with the options to solve this.
  The modifications were made by Timo Jantunen ([e-mail] or
  [e-mail]).  It says that it can be used freely, but making money
  off of it is not allowed.  However, I'm not entirely sure about the
  validity of this copyright, since the original maplay is under the GNU
  General Public License, which does not allow derivative works to have
  a different copyright.

  This can be obtained from
  .



  2.3.5.  splay

  This beta player is another derivative of maplay 1.2 (actually, it is
  a derivative of maplay 1.2+, which is a MS Windows only derivative of
  maplay 1.2).  It adds support for MPEG Layer 3 audio streams.  It is
  also able to play WAV files.  It can also play audio streams received
  over an HTTP connection.

  Another feature of splay is that it can be used as a library (under
  the LGPL), so that it can be used in other programs.  It also tries to
  improve performance by using threading (you need pthread to use this
  feature) and a little inline assembly.

  splay uses a command line interface and an optional X interface (which
  uses QT).

  If after compiling it doesn't work (e.g. it segmentation faults), try
  compiling it again without threading.

  This is by Jung Woo-jae ([e-mail]).

  It can be obtained from splay's home page
  <~jwj95/>.



  2.3.6.  Sajber Jukebox

  This program is a MPEG audio player with a graphical user interface.
  It is based on splay, so it includes support for MPEG audio layers up
  to III.  It is also able to play MPEG audio streams in real time with
  the stream being fed by HTTP.  It is also easy to configure.

  It uses the QT toolkit (at least version 1.2 is required).  It also
  uses the LinuxThreads library (the included binary only works with
  version 0.5).

  The author is Joel Lindholm ([e-mail]).

  The latest version can be obtained from
  .



  2.3.7.  amp

  This beta MPEG audio player only has support for MPEG Layer 3 audio
  streams.  It is able to play directly to the soundcard, and it can
  output to raw PCM or WAV files.  This also gives quite a load on the
  CPU (about 60% on a 133MHz Pentium).

  This was written by Tomislav Uzelac ([e-mail]).  It can be
  freely used and distributed, as long as it is not sold commercially
  without permission (including it in CD-ROMs that contain free software
  is explicitly permitted, though).

  It can be obtained from
  .



  2.3.8.  XAudio

  This alpha library was written to be a fast implementation of an MPEG
  audio decoding library to be used by various GUI front-ends.  It
  supports MPEG audio layers I, II, and III.  It is capable of random
  access to bitstreams.  A command-line interface is included.  A Motif
  (Lesstif) front-end is also included in the Linux version.

  This is by Gilles Boccon-Gibod, Alain Jobart and others.  The front-
  ends to the libary can be freely downloaded.  The library itself must
  be licensed to be used (a source and binary license is available).

  The front-ends to the library can be obtained from the XAudio home
  page <



  2.3.9.  Layer 3 Shareware Encoder/Decoder

  This is actually a converter that converts MPEG Layer 3 audio streams
  to WAV, AIFF, SND, AIFC, or just raw PCM sample files.  The Linux
  version does not directly output the sound to the soundcard.  One has
  to first convert it to some other format.

  However, when you try to play a converted file using sox, you'll
  probably just get noise because the word order in the PCM samples is
  not right (at least on Intel platforms).  You need to give sox the
  option -x to solve this problem.  But there are some players that
  don't have to be told that the word order is wrong, so you might not
  have to worry about this.

  If you have a really fast computer (probably at least a 100Mhz
  Pentium), then you can try to play MPEG Layer 3 streams directly
  without having to first convert the audio file to another format like
  in the following example (this example assumes that you're using sox
  and playing a 44.1 kHz stereo sample).



       $ l3dec foo.mp3 -sto | play -t raw -x -u -w -c 2 -r 44100 -



  The number after -r is the sample rate of the audio stream, and the
  number after -c depends on whether it is mono or stereo (or even
  quad).  If this looks too complicated, you can use something like a
  shell script or an alias.

  This is shareware copyrighted by Fraunhofer-IIS.  A demo version for
  Linux on x86 systems can be obtained from
  .  The demo version only converts layer
  III audio streams.



  2.3.10.  X11Amp

  This beta software is an MPEG audio stream player with a graphical
  interface,  similar to the one used by the Windows program winamp.

  There is no copyright mentioned anywhere (I assume that it can be
  freely used for personal use).  It is maintained by Mikael Alm
  ([e-mail]), Thomas Nilsson ([e-mail]), and Olle
  Hallnas ([e-mail]).

  It can be obtained from X11Amp's homepage <
  Only binaries for Intel Linux and FreeBSD are made available here.


  2.4.  WAV

  Quote from the sox man page:


       These appear to be very similar to IFF files, but not the
       same.  They are the native sound file format of Windows 3.1.
       Obviously, Windows 3.1 is of such incredible importance to
       the computer industry that it just had to have its own sound
       file format.


  These usually have the extension .wav.

  Also see section ``sox'' and ``bplay'' for other WAV players besides
  the ones listed here.



  2.4.1.  wavplay

  This program supports playing and recording with the WAV format.  It
  uses locking so that only one sound may be played at a time.  Its
  locking capabilities can also be used separately from its sound
  playing capabilities.

  In addition to a command-line interface, it also has a Motif
  interface, which can be used with Lesstif.

  It was originally written by Andre Fuechsel ([e-mail]-
  dresden.de), but was evolved to the point of being completely
  rewritten by Warren W. Gay ([e-mail] or
  [e-mail]).

  It can be obtained from
  .



  2.5.  Other stuff

  This section lists stuff that play sound formats that don't deserve a
  separate section (i.e. formats that have only one player available),
  or players that play more than one format.



  2.5.1.  sox

  This program is actually a converter, that is, it converts one sound
  format to another.  However, some versions of sox, when invoked as
  play, plays the sound (the play application in the Sound HOWTO
  probably refers to this).  It supports raw (no header) binary and
  textual data, IRCAM Sound Files, Sound Blaster .voc, SPARC .au
  (w/header), Mac HCOM, PC/DOS .sou, Sndtool, and Sounder, NeXT .snd,
  Windows 3.1 RIFF/WAV, Turtle Beach .smp, CD-R, and Apple/SGI AIFF and
  8SVX formats


  Since somewhere in the 1.3.6x kernels, you might have to make a small
  change in one file to make it play the sound directly.  Namely, you
  may have to change line 179 in sbdsp.c from



       if (abuf_size < 4096 || abuf_size > 65536) {



  to



       if (abuf_size < 1 || abuf_size > 65536) {



  But then again, you may not have to do this.  But doing this won't
  break anything.


  It is written and copyrighted by many people, and can be used for any
  purpose.

  It can be obtained from
    linux.tar.gz>.

  A more recent version by Chris Bagwell ([e-mail]) (based
  on the latest gamma version of the original sox, and includes the
  above fix) can be obtained from
  <  In
  addition, this version supports MS ADPCM and IMA ADPCM WAV formats.



  2.5.2.  bplay

  This beta program plays raw audio, WAV, and VOC files.  It's also able
  to record to these files.  It uses a variety of techniques to get the
  highest speed possible so that it can run acceptably even on slow
  machines.  One of these techniques require that the installed programs
  be setuid root.  The paranoid hoping to use this may want to use the
  Debian package by Ian Jackson ([e-mail]), which disables the
  feature that needs the setuid bit.

  The author is David Monro ([e-mail]).

  It can be obtained from
  .



  2.5.3.  SIDPLAY

  This program emulates the Sound Interface Device chip (MOS 6581,
  commonly called SID) and the Micro Processor Unit (MOS 6510) of the
  Commodore 64.  Therefore it is able to load and execute C64 machine
  code programs which produce music or sound.  In general these are
  independent fragments of code and data which have been ripped from
  games and demonstration programs and have been transferred directly
  from the C64.

  It uses a command line interface by default.  There are also Tk and QT
  interfaces available separately from the main package.

  It is maintained by Michael Schwendt ([e-mail]).

  It can be obtained from SIDPLAY's home page
  <



  2.5.4.  RealAudio Player

  This lets you listen to sound, which is stored in a proprietary
  format, in real time over the Internet without downloading the whole
  sound file first.  It could be used stand alone, but it is really
  intended to be used along with a web browser (the explicitly supported
  ones are Mosaic and Netscape).  It cannot be used without X (you
  wouldn't be able to get it working with Lynx in a text console).

  However, there exists a hack which allows one to run the RealAudio
  player from the text console.  It requires the X virtual frame buffer
  (Xvfb) server to work.  This hack can be obtained from
  .

  This is by Progressive Networks, Inc.  This cannot be redistributed,
  modified etc.  Look at the license for exact details on what you can
  do.  It can be obtained by registering with no cost at the RealAudio
  home page <



  2.5.5.  cat

  One might think what cat, the sometimes overused concatenating
  utility, has to do with playing sounds.  I'll show a use of it through
  an example.



       $ cat sample.voc > /dev/dsp
       $ cat sample.wav > /dev/dsp
       $ cat sample.au > /dev/audio



  Doing a cat of an .au file to /dev/audio will usually work, and if
  you're lucky enough that the file has the correct byte order (for your
  platform) etc., a cat of a sound file that uses PCM samples (like .wav
  or .voc) to /dev/dsp might even sound right.

  This isn't a totally useless use of cat.  It might be useful, for
  example, if you have a sound file that none of your programs
  recognize, and you know that it uses PCM samples, then you might be
  able to get a very approximate idea on how it sounds like this way (if
  you're lucky).



  3.  Other useful sound utilities

  This section has nothing to do with the actual playing of sound files.
  Rather, it is a collection of some sound utilities that one might find
  useful.


  3.1.  volume

  This is a simple command line interface for controlling the volume
  (what else could it be?).  It also has a separate program with a
  Tcl/Tk interface included in the package for controlling the volume
  and playing .au sound files.  A very simple Tcl/Tk CD player is also
  included.

  This is Freeware and it is written by Sam Lantinga
  ([e-mail]).

  It can be obtained from
  .



  3.2.  Sound Studio

  This is a Tcl/Tk application that supports playback, recording, and
  editing of digital sound using sox.  It includes sox in the
  distribution to avoid compatibility problems.

  This was written by Paul Sharpe and N. J. Bailey
  ([e-mail]).  It may be freely used and redistributed if
  a postcard is sent.


  It can be found at Sound Studio's home page <
  eng.leeds.ac.uk/staff/een6njb/Software/Studio/screens.html>.



  3.3.  Tickle Music

  This beta Tcl/Tk program is a music file browser that allows you to
  play various sound formats as long as an appropriate program to play
  it is on your system.  By default gmod is used for playing MOD files
  and mp for playing MIDI files (you can change the source to use other
  programs).

  It is written and copyrighted by Shannon Hendrix ([e-mail]
  or [e-mail]).

  It can be obtained from
  .



  4.  References


  1. The documentation included with the applications in this document.

  2. The Linux Sound HOWTO.  It can be found at the Linux Documentation
     Project <
  3. Linux MIDI and Sound Applications
     <~dlphilp/linux_soundapps.html>

  4. Programmer's Guide to OSS <

  5. SoX home page <