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Ken Davies Web
Audio Tutorial
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MIDI | Audio
Formats | MOD |
Web Audio Tutorial For Music Professionals
This page built December 2000
Several audio formats are useful for performers, producers, arts organizations, businesses, sheet music publishers and composers in displaying their audio work to the public via the web. This tutorial will cover the main ones as well as detailing some of the problems and advantages to be considered. As we begin the year 2001, most computers, whether Macintosh or PC Windows, are suitably equipped to play a variety of sound file formats and software, shareware and freeware are abundant. We will discuss various audio formats, including MIDI, AIFF, WAVE, MOD, MP3, RMF, QuickTime, WMA, Real Audio, Liquid Audio and streaming audio.
Some of my seemingly simplistic explanations, when they appear, are geared to be meaningful and helpful to those coming from the musician/composer background rather than an audio/engineering or communications/computer programming background. For that reason I deliberately venture deeply into neither tech concepts nor jargon beyond a need-to-know point. Other topics such as audio physics, web design, internet promotion and music promotion are covered elsewhere. Much will be confined to Mac and Windows because few musicians, outside of some academic environments and IRCAM, are working with other platforms such as Unix.
Audio, multi-media player software (free
downloads)
PCs generally use Windows
Media Player from Microsoft.
Macs (Power PC only) generally use QuickTime
4.1 (or the latest update) from
Apple.
Both softwares are available for the opposite
platform. Both play almost any audio and/or video media. Both are, at this
writing, the most common.
Sound Format Basics
Computer architecture, recording technology,
radio-TV and telephone wire physics are partly responsible for certain
"unbreakable laws" concerning web and sound files. Sound files are
about CODECs (COmpression/DECompression) of digitized recorded sound. There
are different arrangements by which sound can be compressed, thus different
companies with different methods and names trying to make theirs the "best"
or at least the most widespread (dare we say "popular?").
A few reference numbers should be kept in mind as they tend to be the bit rate centers for many other things that occur in this realm. In digital music, sound waves are sliced up into a package of averages with the slices (the sample rate or bit rate) given a number (a "value"). A good quality sound wave (bit) is 44.1 samples per second (kilohertz or kHz) and that is the rate that quality CDs are made. By comparison, cheap AM radio quality is about 22 kHz. The sliced up sound wave samples are represented by a string of numbers and those numbers can be stored in a computer file, hard disk or tape and is called a WAVE file.
WAVE files are huge. For one second of
sound, you need you need 44.1 x 2 computer bytes = 88.2 bytes of memory
(double that for 2-channel stereo!). That means you need nearly 10.5 MegaBytes
(MB) for one minute of music. Since modems may receive downloads of these
MBs at the rate of 28.8 or maybe 33.6 bps (bytes per second), that's a
l-o-n-g wait for a minute of music. It is that factor that kept music from
being a major part of the internet for such a long time. That's why programmers
are developing CODECs to compress the file sizes yet keep the perception
of high quality sound. Each CODEC may end up with a slightly different
set of bit rate numbers, relative to it's function and the computer platform
it may be designed for. Therefore, they are not "all equal and interchangeable."
But those individual numbers are more the programmer's and audio folk's
concern. Sufficient for the musician is to understand that the problem
is technically one of running big music through a small space (bandwidth)
and having it sound good enough to get the desired result. And a given
desired result (or "quality") will depend somewhat on the broadcast or
promotional purpose.
top
| MIDI files |
MIDI is not really a sound/audio format at all, since its files contain no sound, but rather contain sequential event data that can be realized as sound when channeled through a MIDI playback instrument like a digital sample player ("synthesizer" to most folks). Very simply, a MIDI file tells the synth what to play when and how loud. Since its development in the early 1980s, MIDI (Musical Instrument Digital Interface) has remained a very useful tool for presenting music on the web. MIDI technology is what drives most notation and sequencer software applications.
Tips:contain no sounds (event data only) and thus are very small files cross-platform media so will perform equal well on Mac or PC easily and quickly emailed as attachments from one computer to another can add a bit of aural decoration (or an annoyance) to a web page - (avoid embedding the files; let the viewer click a link to hear or download) in web browser technology, can be limited in sonic scope (forget electronic experimentally designed sounds) many MIDI files sites featuring collections from classical to popular. good for performances of works in themselves (especially keyboard) excellent vehicle for composers and publishers to aurally demonstrate nearly any type of new music except perhaps vocal, choral, large instrumental like orchestral symphonic works, and sonic design specific works like electronic music or specially edited sounds (unless files are for download to be played through a keyboard sample player [synth] or workstation) Composers/publishers/performers should consider offering demo MIDI files in two forms: 1) individually for download/play and 2) as groups of files in a zipped pack. Mac users with the latest free Stuffit Expander from Aladdin Systems can readily unzip PC-made zip files. MIDI files are of three types:
Type 0 consists of one track with all the data merged therein.
Type 1 retains all the individual tracks on which data was recorded.
Type 2 - saves the file as separate tracks or staves and also includes the tempo and time signatures for each track.
Resources
5 excellent resource pages from Charles
Kelly
1-ABCs
of Using MIDI Files on the Net - To the point tutorials for beginners.
Only what absolutely need to know. Not Mac-specific.
2-Macintosh
User's Internet Guide - a wealth of info and downloads for MIDI utilities,
tools, MIDI sites and resources from Charles Kelly.
3-Guidelines
for HTML Writers of MIDI File Pages by Charles Kelly.
4-Links
for Writers of MIDI File Pages by Charles Kelly.
5-How
to Design a Good MIDI File Site by Charles Kelly.
Charles
Belov's MIDI Tips - also includes web server vendor tips like this
crucial one (this helped me and my ISP tech clear up my web MIDI
problem):
Many MIDI files fail because a faulty
MIME type is being sent out by the web server. Here is what an ISP server
should be setting up for MIDI:
Tutorials
Exploring
MIDI - by Peter J. Raschke, School of Music Northwestern University.
What
is MIDI - tutorial from Beatnik,
a software for playing and developing Rich
Music Format (RMF) audio files.
Basic
Tutorials for MIDI Users - covers basics of MIDI, much info is PC oriented,
hardware, configurations & trouble-shooting, sequencing tips, useful
charts, info on some Roland products, history and development of MIDI.
Music
Technology Tutorials and Articles by Michael Tylor - has some tips
for church musicians.
Playing
(embedded) MIDI on your Web Pages - how to write code to make your
MIDI files play in Nescape or Internet Explorer.
How
to Embed MIDI files into your Web Site - shows code
MMA - MIDI
Manufacturers Assn - The MMA was formed in 1984 as a "trust" to keep
and enhance the MIDI specification so that no one company would have control.
DownLoad
Sounds (DLS) format - (adopted 1998) The DLS format makes it possible
for musicians composing for Internet or CD-ROM applications to use sounds
of their own design, rather than limiting their compositions to the 128
General MIDI sounds that are typically available on multimedia computers.
MIDI
Tools & Resource - big list from Harmony Central, includes articles,
tutorials, software sites...
MIDI
Options for Web Authors - from the Crescendo web site
| Piano | Bass | Reed | Synth F/X |
|---|---|---|---|
| 01.Acoustic Piano
02.BriteAcou Piano 03.Electric Grand Piano 04.Honky Tonk Piano 05.Elec.Piano 1 06.Elec.Piano 2 07.Harsichord 08.Clavichord |
33.Acoustic Bass
34.El.Bass Finger 35.El.Bass Pick 36.Fretless Bass 37.Slap Bass 1 38.Slap Bass 2 39.Synth Bass 1 40.Synth Bass 2 |
65.Soprano Sax
66.Alto Sax 67.Tenor Sax 68.Baritone Sax 69. Oboe 70.English Horn 71.Bassoon 72.Clarinet |
97.FX1 Rain
98.FX2 Soundtrack 99.FX3 Crystal 100.FX4 Atmosphere 101.FX5 Brightness 102.FX6 Goblins 103.FX7 Echoes 104.FX8 Sci-Fi |
| Chromatic Percussion | Strings | Pipe | Ethnic |
| 09.Celesta
10.Glockenspiel 11.Music Box 12.Vibraphone 13.Marimba 14.Xylophone 15.Tubular Bells 16.Dulcimer |
41.Violin
42. Viola 43.Cello 44.Contra Bass 45.Tremelo Strings 46.Pizz. Strings 47.Orch. Strings 48.Timpani |
73.Piccolo
74.Flute 75.Recorder 76.Pan Flute 77.Blown Bottle 78.Shakuhachi 79.Whistle 80.Ocarina |
105.Sitar
106.Banjo 107.Shamisen 108.Koto 109.Kalimba 110. Bagpipe 111. Fiddle 112. Shanai |
| Organ | Ensemble | Synth Lead | Percussive |
| 17.Drawbar Organ
18.Perc. Organ 19.Rock Organ 20.Church Organ 21.Reed Organ 22.Accordian 23.Harmonica 24.Tango Accordian |
49.String Ens.1
50.String Ens.2 51.Synth.Strings 1 52.Synth.Strings 2 53.Choir Aahs 54. Voice Oohs 55. Synth Voice 56.Orchestra Hit |
81.Lead1 Square
82.Lead2 Sawtooth 83.Lead3 Calliope 84.Lead4 Chiff 85.Lead5 Charang 86.Lead6 Voice 87.Lead7 Fifths 88.Lead8 Bass Ld |
113.TinkerBell
114.Agogo 115.SteelDrums 116.Woodblock 117.TaikoDrum 118.Melodic Tom 119.SynthDrum 120.Reverse Cymbal |
| Guitar | Brass | Synth Pad | Sound F/X |
| 25.Acoustic Guitar
26.SteelAcous. Guitar 27.El.Jazz Guitar 28.Electric Guitar 29.El. Muted Guitar 30.Overdriven Guitar 31.Distortion Guitar 32.Guitar Harmonic |
57.Trumpet
58.Trombone 59.Tuba 60.Muted Trumpet 61.French Horn 62.Brass Section 63.Synth Brass 1 64.Synth Brass 2 |
89.Pad1 New Age
90.Pad2 Warm 91.Pad3 Polysynth 92.Pad4 Choir 93.Pad5 Bowed 94.Pad6 Metallic 95.Pad7 Halo 96.Pad8 Sweep |
121.Guitar Fret Noise
122. Breath Noise 123.Seashore 124.BirdTweet 125.Telephone 126.Helicopter 127.Applause 128.Gunshot |
| Audio File Formats |
Until the advent of RealAudio, MP3, and other modern Web audio contenders, AU, AIFF, WAV, and MIDI files accounted for most of the sound heard on the Web. Many of these formats use some or all of three elements: compression schemes to reduce file sizes, a server to send or sometimes "stream" the music, and a player (or plug-in) to play the music on the client's computer.
The formats below are merely a few of the main ones with which the musician should have a passing catagorical acquaintance. Available audio file players for Mac or PC can handle most of these as well as be able to convert the files (think "re-orchestrate the data") so the computer can play them. There are also individual shareware and freeware utilities that can convert various PC files to Mac and vice-versa. It is not uncommon to find that vast numbers of music fans are far more familiar with these than many music professionals.
The following are FILE FORMATS
Audio Tutorials & Resources
Guide
to Web Publishing - Audio File Formats - simple overview
MP3
and Digital Multi-media Tutorials
Multi-media
Audio & mp3 - from Web Monkey
All
About Audio - especially for Cakewalk and PC related
Adobe
Tutorial: Web Audio - especially as applies to Adobe's GoLive web editor
Understanding
Digital Audio Formats - Microsoft. Covers mp3 and Windows Media Audio
Zap's
Music On The Net Tutorial - Formats - somewhat technically detailed
How
to Embed WAVE files into your Web Site - shows code
Guide
to Internet Music & Sound - from Music Stream
Streaming
Media 101 - Tutorial - from RealNetworks (Real Audio)
www.realnetworks.com
- info on multi-media development with Real Audio
Web
Audio Workshop - from Web Developers Journal
Embed
Sound - how to code the web page
IRCAM - Pierre Boulez' place. This is for the majors.
| The MOD (Module) |
Now that you have a general idea of MIDI and WAVE files, we can move on to MOD files which enjoyed considerable popularity among some PC users. A Module (MOD for short) is sort of a hybrid, a mixture of MIDI and WAVE. The MIDI file depends on the instruments, that are on your sound card or in your external sound module. A MOD file has the sequencing information AND the instruments (in the form of 'samples') in it. These samples can be looked upon as short WAVE files of one note of an instrument. It's like a MIDI file with a soft-synth (software synthesizer) inside.
It is up to you, the MOD composer, what samples you wish to include in the MOD file. This way you're not dependent on the instruments of the sound card, which means that the song will sound the same on any computer and you're not limited to the instruments and effects that are built into the sound card. On the other hand, you are limited in the number of samples you can put in a MOD file and changes are less easy to make. When you buy a better sound card or sound module, all your MIDI files will sound better, without any (relevant) changes. Whereas, in a MOD file the quality is laid down 'forever'. Also the size of MOD files is larger, because the wave samples are included and good samples take a lot of space.
For more about MOD files, visit:
news:alt.music.mods
or
news:alt.binaries.sounds.mods
www.kendavies.net/resources/webaudio.html
