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<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta name="Author" content="Rubywand"> <meta name="GENERATOR" content="Mozilla/4.75 [en] (Win95; U) [Netscape]"> <title>R015SNDNMUS Csa2 html</title> </head> <body> <address> <a NAME="top"></a><font color="#FFFFFF">.</font><font color="#666666"><font size=-1>The official Csa2 (comp.sys.apple2) Usenet newsgroup Apple II FAQs originate</font></font></address> <address> <font size=-1><font color="#666666"> from the</font> <b><font color="#009900">Gr</font><font color="#FF9900">o</font><font color="#FF0000">u</font><font color="#CC33CC">n</font><font color="#3366FF">d </font></b><font color="#666666">Apple II site. Ground Apple II administrator: Steve Nelson</font></font></address> <br><b><tt><font color="#FFFFFF"><font size=-2>.</font></font><font color="#666666">Csa2 FAQs-on-Ground Resource file: R015SNDNMUS.htm</font></tt></b> <br><b><font color="#FFFFFF"><font size=+2>. .<a href="A2FAQs1START.html"><img SRC="entrance.jpg" BORDER=0 height=14 width=69></a>..<a href="A2FAQs2CONTENT.html"><img SRC="contents.jpg" BORDER=0 height=14 width=67></a>.</font></font></b> <br> <br> <p><b><font size=+3>Apple II Sound & Music</font></b> <p> <b>Version 1.51 (2-JAN-97)</b> <p><b> Written by Ian Schmidt (irsman@iag.net)</b> <br> <p><tt> Thanks for corrections and updates to Joe Walters, Dave Lyons, Dave</tt> <br><tt>Huang, Mitchell Spector, and Scott Gentry.</tt> <p><tt> Send additional questions/comments/blatent error reports to</tt> <br><tt>irsman@iag.net.</tt> <p><tt>A quickie what's new:</tt> <p><tt> * Added to the Other Systems table.</tt> <br><tt> * Various additional info and editing.</tt> <br><tt> * Started the 8-bit section</tt> <p><tt> I know some of you emailed me info on the Phasor, Mockingboard, etc, a</tt> <br><tt>while ago but I can't find it now, so please e-mail anything you've got to</tt> <br><tt>irsman@iag.net. Also, additional info (like the name) on the program which</tt> <br><tt>plays GS sampled sounds on 8-bit IIs would be a good thing.</tt> <br> <p><tt> Table of Contents</tt> <p><tt> * An introduction to music and sound</tt> <br><tt> * 8-bit music and sound</tt> <br><tt> * Types of sound files used on the IIgs</tt> <br><tt> * How to digitize sounds</tt> <br><tt> * How to edit sounds</tt> <br><tt> * Types of music files</tt> <br><tt> * An overview of SoundSmith-style editors</tt> <br><tt> * An overview of MIDI</tt> <br><tt> * Technical specifications for the IIgs Ensoniq chip</tt> <br><tt> * About IIgs stereo cards</tt> <br><tt> * What about them other machines? And video games?</tt> <br><tt>_________________________________________________________________</tt> <br> <br> <p><tt>An introduction to music and sound on computers</tt> <p><tt> Music and sound have been a computerized pursuit since at least the</tt> <br><tt>1960s, when enterprising hackers discovered that by programming the large</tt> <br><tt>mainframes of the time to do different operations, different tones could be</tt> <br><tt>generated on a common AM radio from the interference (this is still a</tt> <br><tt>problem today :-).</tt> <p><tt> Early synthesizers developed at the time (known as Mellotrons)</tt> <br><tt>consisted of a huge bank of tape loops, with each key playing a different</tt> <br><tt>tape. Primitive analog tone generators were also in use. These early</tt> <br><tt>synthesizers first got wide industry exposure via Walter aka Wendy (never</tt> <br><tt>mind) Carlos' "Switched-On Bach" album.</tt> <p><tt> At this time (mid to late 60s), Robert Moog developed the direct</tt> <br><tt>ancestors of today's synthesizer. Moog's synthesizers were programmed via</tt> <br><tt>'patch bays', wherein the user would connect a series of jacks in a specific</tt> <br><tt>configuration via patch cords to get a certain tone. This use of the word</tt> <br><tt>'patch' for a sound setting on a synthesizer persists, despite that today a</tt> <br><tt>'patch' is usually a data file stored on disk or in ROM.</tt> <p><tt> The Moog's debut in a Top 40 song was Del Shannon's "Runaway". A Moog</tt> <br><tt>was used along with a tube-based analog synthesizer called a theremin in the</tt> <br><tt>Beach Boys' classic "Good Vibrations". The possibilities of synthesizers</tt> <br><tt>weren't really exploited until the onslaught of 70s 'art-rock' bands such as</tt> <br><tt>the Who, Supertramp, ELP (Emerson, Lake, and Palmer), Genesis, Yes, Pink</tt> <br><tt>Floyd and Rush.</tt> <p><tt> Synthesizers have continued to advance to the point where they are now</tt> <br><tt>the only instrument needed to make a typical Top 40 or rap album. This was</tt> <br><tt>foreseen somewhat by Boston, who included a "No Keyboards!" logo on one of</tt> <br><tt>their early albums despite the obvious inclusion of a Hammond organ on</tt> <br><tt>several songs. Computer control of music developed somewhat later, however.</tt> <br><tt>Several companies in the early 1980s had competing systems for allowing</tt> <br><tt>electronic synthesizers to interface to computers and each other, Roland's</tt> <br><tt>"CV-Gate" system being among the most popular.</tt> <p><tt> Around 1983 or so, a group of companies developed the now ubiqitous</tt> <br><tt>MIDI (Musical Instrument Digital Interface) standard. It is now very</tt> <br><tt>difficult to find a synthesizer without MIDI capabilities, and all popular</tt> <br><tt>computers can be interfaced to MIDI instruments, including the Apple II.</tt> <p><tt> The first development after MIDI was introduced was the "sequencer"</tt> <br><tt>program, a program which allowed the recording and playback of MIDI data</tt> <br><tt>streams, as well as sophisticated editing functions. This allowed perfect</tt> <br><tt>playback of songs every time, as well as more advanced functionality such</tt> <br><tt>as the ability to synchronize MIDI data with SMPTE (Society of Motion</tt> <br><tt>Picture and Television Engineers) time code, a fact which made it very</tt> <br><tt>simple to add MIDI-based music to television shows and theatrical films and</tt> <br><tt>synchronize to a resolution finer than 1 frame. SMPTE and MIDI were used</tt> <br><tt>heavily in the production of the soundtrack for the recent blockbuster</tt> <br><tt>"Jurassic Park" for example.</tt> <p><tt> At about the same time as the first sequencers were arriving,</tt> <br><tt>computers began to get sound chips with some semi-decent capabilities.</tt> <br><tt>Machines such as the TI-99/4A and Atari 800 had chips capable of playing at</tt> <br><tt>least 3 independent tones at any one time. However, the tones were preset,</tt> <br><tt>usually to a square wave, which has very little musical interest.</tt> <p><tt> This went to the next step when a young engineer developed the SID</tt> <br><tt>sound chip for the Commodore 64 computer. The SID chip could play 3 tones at</tt> <br><tt>once [plus 1 channel devoted to 'white noise' percussive sounds], and each</tt> <br><tt>of the tones could be selected from a range of several waveforms. In</tt> <br><tt>addition, advanced effects such as "ring modulation" were avalible on this</tt> <br><tt>chip. The C=64 soon allowed many to compose some amazing tunes, but the</tt> <br><tt>best was yet to come.</tt> <p><tt> The engineer who designed the SID went on to join a company called</tt> <br><tt>Ensoniq, where he designed the DOC (Digital Oscillator Chip) which powered</tt> <br><tt>the company's now legendary Mirage synthesizer. The Mirage was unique in</tt> <br><tt>that it was the first major synthesizer to offer sampling, wherein you could</tt> <br><tt>digitally record any sound you wanted, from trumpets to snare drums to water</tt> <br><tt>dripping, and use it as an instrument. Best of all, the DOC chip could play</tt> <br><tt>up to 32 samples at any one time, making it useful to emulate a whole</tt> <br><tt>orchestra with one Mirage. The DOC chip also powered Ensoniq's ESQ-1 and</tt> <br><tt>SQ-80 synthesizers.</tt> <p><tt> Now, to get some Apple II-ish relevance. During the design of the</tt> <br><tt>Cortland (aka IIgs), Apple was planning on using a chip not unlike the one</tt> <br><tt>on the Mac II series. This chip played 4 samples at once, but was limited</tt> <br><tt>in it's stereo capabilities (you got 2 samples on the left, and 2 on the</tt> <br><tt>right, and that's it) as well as overall flexibility (it's limited to 1</tt> <br><tt>fixed sampling rate of 22,052 Hz).</tt> <p><tt> Luckily, Ensoniq sent a sample of the DOC chip to Apple, and it ended</tt> <br><tt>up in the hands of a music enthusiast working on the IIgs project. This</tt> <br><tt>engineer fought with management until they decided to use the DOC chip for</tt> <br><tt>the IIgs. However, up until nearly the last minute, the DOC and it's 64k</tt> <br><tt>of RAM were to be an extra-cost feature, which would have killed the GS</tt> <br><tt>music software market dead. Luckily, price drops on components allowed the</tt> <br><tt>DOC to be standard, so all IIgs owners could hear great sound.</tt> <p><tt> Back to generalized things, the next development was to combine</tt> <br><tt>sampling and sequencing software on capable computers. This resulted in the</tt> <br><tt>*Tracker genre on the Amiga, as well as Music Construction Set, Music</tt> <br><tt>Studio, and other programs on many platforms. These programs typically had a</tt> <br><tt>sequence file and a series of sample files used as instruments, with some</tt> <br><tt>notable exceptions (the *Tracker series on the Amiga had all-in-one</tt> <br><tt>'modular' files, hence the name MOD).</tt> <br><tt>_________________________________________________________________</tt> <br> <p><tt>8-bit music and sound</tt> <p><tt> The 8-bit IIs are quite underpowered in the sound department compared</tt> <br><tt>to the IIgs. However, anyone who's played Dung Beetles or Sea Dragon knows</tt> <br><tt>that some pretty sophisticated stuff is still possible. The 8-bit sound</tt> <br><tt>normally consists simply of an ability for programs to make the speaker</tt> <br><tt>click.</tt> <p><tt> If a program toggles the speaker very fast, tones are generated. And</tt> <br><tt>using other techniques beyond the scope of this FAQ, you can even play</tt> <br><tt>digitized samples on the speaker, although the quality isn't very good. This</tt> <br><tt>capability is best known from it's use in some of the classic Apple II</tt> <br><tt>games, but there is also a program available that allows you to play any</tt> <br><tt>arbitrary IIgs-style sampled sound on any Apple II.</tt> <br><tt>_________________________________________________________________</tt> <br> <p><tt>Types of sound files found on the IIgs</tt> <p><tt> Several types of sample files are used. Here are the most common.</tt> <br> <p><tt>Name Ext. FType Description</tt> <br><tt>---------------------------------------------------</tt> <br><tt>Raw no std. BIN Contains only raw sample data. The</tt> <br><tt> auxtype is normally the sample rate</tt> <br><tt> divided by 51. (See section CA for</tt> <br><tt> more on why this is).</tt> <p><tt>ACE .ACE $CD Contains raw sample data compressed with</tt> <br><tt> ACE, Apple's Tool029 sound compressor.</tt> <p><tt>ASIF no std. $D8 Contains sample data plus additional data.</tt> <br><tt> Notable due to its use by SoundSmith.</tt> <p><tt>AIFF .AIFF $D8 Interchange format popular on the</tt> <br><tt> Macintosh. Not used much on the IIgs.</tt> <br><tt>Hyper</tt> <br><tt>Studio no std. $D8 Contains raw or ACE compressed data plus</tt> <br><tt> additional information.</tt> <p><tt>rSound no std. $D8 Resource fork contains one or more rSound</tt> <br><tt> and rResName resources. Used by HyperCard</tt> <br><tt> IIgs and the Sound CDev.</tt> <br><tt>_________________________________________________________________</tt> <br> <p><tt>An introduction to sampling</tt> <p><tt> Sampling is conceptually simple; an incoming analog sound signal is</tt> <br><tt>converted to a digital number (0-255 on the IIgs). Getting good samples</tt> <br><tt>depends on a number of factors:</tt> <p><tt>* Sampling rate. This is how often in samples per second the</tt> <br><tt> incoming signal is actually noticed and saved. In general, you</tt> <br><tt> want to have a sampling rate of twice the frequency of the highest</tt> <br><tt> pitch sound you intend to sample. (The reasoning behind this is</tt> <br><tt> known as the Nyquist Sampling Theorem). Compact discs sample at</tt> <br><tt> 44,100 Hz, which means they can accurately track signals up to</tt> <br><tt> 22,050 Hz, beyond the range of human hearing. Long-distance</tt> <br><tt> telephone calls are sampled at 8,000 Hz, since the characteristic</tt> <br><tt> part of human voices is generally from 1000-3000 Hz.</tt> <br><tt>* Stereo card quality and shielding (the Audio Animator makes the</tt> <br><tt> best samples of any card I've tried, by far).</tt> <br><tt>* Input signal level (the higher the better, except that there is a</tt> <br><tt> threshold known as the 'clipping level' above which the sampler</tt> <br><tt> will be unable to track the signal. Analog tape recorders do</tt> <br><tt> something very similar).</tt> <p><tt> Once a sample is made, it can be manipulated in a variety of ways via</tt> <br><tt>mathematics. Because this processing is digital, no degradation of the</tt> <br><tt>signal can occur, unlike with analog processing. Some effects which can be</tt> <br><tt>done include:</tt> <p><tt>* Cut and pasting parts of the sample around.</tt> <br><tt>* Mixing/overlaying two samples.</tt> <br><tt>* Flanger/Chorus effects.</tt> <br><tt>* Amplification and deamplification.</tt> <br><tt>* Echoing</tt> <br><tt>* Filtering and equilization</tt> <p><tt>and much more...check out a modern rack-mounted guitar digital signal</tt> <br><tt>processor for all the things possible :)</tt> <p><tt> To digitize a sound (I'll use AudioZap as the example, others are</tt> <br><tt>similar):</tt> <p><tt>* Hook everything up.</tt> <br><tt>* Check the oscilloscope. The wave should be barely touching the top</tt> <br><tt> and bottom of the 'scope. Any higher and the sound is clipping;</tt> <br><tt> any lower and you'll get a poor quality recording. Adjustment</tt> <br><tt> methods vary by card; for the Sonic Blaster card AZ can adjust it</tt> <br><tt> in software. Otherwise, consult your card's manual.</tt> <br><tt>* Select a recording rate (lower numbers on AZ = faster).</tt> <br><tt>* Click Record and cue up your tape or CD.</tt> <br><tt>* Select Ok and then start the tape or CD.</tt> <br><tt>* Click the mouse and stop the tape or CD when you are done.</tt> <p><tt> You've just made a sample! congratulations! Experiment...you can't hurt</tt> <br><tt>anything, but may discover fun/neat things to do!</tt> <br> <p><tt>_________________________________________________________________</tt> <br> <br> <p><tt>Some basics on editing sounds.</tt> <p><tt> (This section attempts to be program-independent, but in some cases</tt> <br><tt> specific refrences to AudioZap may sneak in :-)</tt> <p><tt> I'll assume you now have a sound loaded up, and whatever program is</tt> <br><tt>showing you a nice wave graph. Now, you can pick out portions of the wave by</tt> <br><tt>simply clicking and dragging the mouse over a part of the wave, and letting</tt> <br><tt>go when you have as much as you want. If you now try to Play, you'll only</tt> <br><tt>hear the portion you have selected. If you need to adjust your selection</tt> <br><tt>range, many programs allow you to shift or apple-click and extend the</tt> <br><tt>endpoints instead of just starting over with a new range.</tt> <p><tt> Once you have an area selected, you can cut/copy/paste/clear just like</tt> <br><tt>you would text in a word processor. When pasting a waveform, you simply</tt> <br><tt>click once where you'd like, and select Paste. The program inserts the</tt> <br><tt>previously cut or copied piece of wave and moves the wave over to make room,</tt> <br><tt>just like with a word processor.</tt> <p><tt> For more specific information, consult the documentation for the</tt> <br><tt>program you use.</tt> <p><tt>_________________________________________________________________</tt> <br> <p><tt>AE Types of music files</tt> <p><tt>Name Ext. FType Description</tt> <br><tt>---------------------------------------------------</tt> <br><tt>MCS None MUS Music Construction Set tune.</tt> <br><tt>TMS .SNG BIN Music Studio song.</tt> <br><tt>SS None MUS SoundSmith song.</tt> <br><tt>NTMOD None INT NoiseTracker GS module</tt> <br><tt>NTSNG None BIN NoiseTracker GS song.</tt> <br><tt>MOD None $F4 Amiga ProTracker module ($F4 is temporary).</tt> <br><tt>MIDI .MID MDI Standard MIDI file.</tt> <br><tt>_______________________________________________________________</tt> <br> <br> <p><tt>A Brief Overview of SoundSmith Style Editors</tt> <p><tt> SoundSmith (and all other MOD derived editors) use a very simplistic</tt> <br><tt>way to representing music, to wit:</tt> <p><tt>0 C5 1000 --- 0000</tt> <br><tt>1 --- 0000 --- 0000 ... additional tracks here</tt> <br><tt>2 G5 33FF G5 53FF</tt> <br><tt>3 --- 0000 --- 0000</tt> <br><tt>4 C5 1000 --- 0000</tt> <p><tt> This is often known as a 'spreadsheet' format since there are rows and</tt> <br><tt>columns much like a spreadsheet. Let's take a look at an individual cell:</tt> <br> <p><tt> Number of cell</tt> <br><tt> | Instrument number</tt> <br><tt> | | Effect data</tt> <br><tt> | | /|</tt> <br><tt> 2 G5 33FF</tt> <br><tt> /\ |</tt> <br><tt> || Effect number</tt> <br><tt> ||</tt> <br><tt> Note and octave</tt> <br> <p><tt> For this note, it's #2 of 63 in the pattern, it's a G in octave 5,</tt> <br><tt>using instrument number 3, effect 3, and data FF. What effect 3 actually</tt> <br><tt>means depends on the tracker in question. On SoundSmith and derivatives, it</tt> <br><tt>means "Set the volume to --", in this case set it to $FF (255) which is the</tt> <br><tt>maximum.</tt> <p><tt> Now, into a larger structure. 64 lines of cells m akes up a block, or</tt> <br><tt>pattern as it is sometimes called. (MED on the Amiga allows blocks of</tt> <br><tt>varying lengths, but we won't consider those here). You can terminate a</tt> <br><tt>block early with a special effect. On the Amiga, an actual effect number is</tt> <br><tt>used. On SoundSmith, entering the note/octave as NXT makes that line of</tt> <br><tt>cells the last line played in that block.</tt> <p><tt> Now that we've covered cells and blocks, we can get into the</tt> <br><tt>large-scale structure of things. To make a complete song, we can give the</tt> <br><tt>player a 'block list' which tells it to play a specific sequence of blocks</tt> <br><tt>in a specific order. For instance, we could have it play block 4, then block</tt> <br><tt>0, then block 1, then block 2, then block 2. An entry in the block list is</tt> <br><tt>known as a 'position'. MOD-derived formats typically allow 128 positions,</tt> <br><tt>and 64 (MOD) or 71 (SoundSmith) blocks.</tt> <br> <p><tt>A Practical Example:</tt> <p><tt> Crank up MODZap 0.9 or later and a favorite tune. Set it to the</tt> <br><tt>"Classic Player". Now, remember those numbers you never understood before,</tt> <br><tt>off to the left of the scrolling cells? Here's what they mean, in terms of</tt> <br><tt>what you just learned: *grin*</tt> <br> <p><tt>This is the # of entries in the block list > 35 --- 0000</tt> <br><tt>This is the current block list entry playing > 04 --- 0000</tt> <br><tt>This is the block # currently playing > 01 --- 0000</tt> <br><tt>This is the current cell # in the current block > 36 A#4 0384</tt> <p><tt> As you watch, the current cell # will normally (barring certain</tt> <br><tt>effects) smoothly go from 00 to 63. When it hits 63, it will go to 00 again</tt> <br><tt>and the current block list entry number will increment by 1. When it does,</tt> <br><tt>the current block number will change if needed (remember, a block can appear</tt> <br><tt>multiple places in the block list).</tt> <br><tt>_________________________________________________________________</tt> <br> <p><tt>An Overview of MIDI</tt> <p><tt> MIDI is a specification developed to allow computers and electronic</tt> <br><tt>musical instruments to communicate with each other. Physical MIDI hookups</tt> <br><tt>can get rather complicated; here is a brief primer:</tt> <p><tt> MIDI hookups are a lot like your stereo, in that each device has IN and</tt> <br><tt>OUT ports. However, MIDI devices also have a port known as THRU, which</tt> <br><tt>retransmits information from the In port (more on why this is a Good Thing</tt> <br><tt>later). MIDI devices are thus connected in a modfified daisy-chain</tt> <br><tt>arrangement, with the Out of the master (usually a computer) connected to</tt> <br><tt>the In of Slave #1, and Slave #1's Thru connected to Slave #2's In, and so</tt> <br><tt>on. The Outs of all devices go to the In of the master.</tt> <br> <br> <p><tt>Here is a diagram of a simple hookup:</tt> <br> <p><tt> -----------------------------------</tt> <br><tt> | ---------------- |</tt> <br><tt> | | ___________ | ----- |</tt> <br><tt> | | | | | | | |</tt> <br><tt> In In Out In Out Thru In Out Thru</tt> <br><tt> Computer Synth Drum Machine</tt> <br><tt> (Master) (Slave #1) (Slave #2)</tt> <br> <br> <p><tt> MIDI is based on 16 'channels'. Each channel is typically assigned to</tt> <br><tt>one specific device you have connected in your chain. In the example above,</tt> <br><tt>you might have the synth set to listen to channels 1-9, and the drum machine</tt> <br><tt>set to listen to channel 10 (this is a typical assignment).</tt> <p><tt> With this setup, when the computer transmits a note on channel 10, it</tt> <br><tt>will first go to the IN of the synth, which will simultaneously retransmit</tt> <br><tt>it via it's THRU port and note that it doesn't want to use the data. The</tt> <br><tt>note will then appear on the drum machine's IN port. The drum machine will</tt> <br><tt>transmit it on it's THRU port (to which nothing is connected in the example)</tt> <br><tt>and start the note.</tt> <p><tt> This allows flexibility; if for instance you wanted you could connect a</tt> <br><tt>second drum machine with different sounds, set it to channel 10 also, and</tt> <br><tt>have a unique mix :)</tt> <p><tt> I will not cover MIDI recording and editing here, to avoid getting too</tt> <br><tt>technical :)</tt> <br><tt>_________________________________________________________________</tt> <br> <p><tt>Technical Specs for the GS Ensoniq chip</tt> <p><tt> The 5503 Ensoniq Digital Oscillator Chip (DOC) contains 32</tt> <br><tt>fundamentalsound-generator units, known as 'oscillators'. Each oscillator is</tt> <br><tt>capable of either making an independent tone by itself, or of being paired</tt> <br><tt>up cooperatively with it's neighbor in a pairing known as a 'generator'. The</tt> <br><tt>generator arrangement is used by most programs, for it allows more</tt> <br><tt>flexibility and a thicker, lusher sound.</tt> <p><tt> The DOC plays 8-bit waveforms, with the centerline at $80 (128</tt> <br><tt>decimal). $00 (0 decimal too) is reserved for 'stop'. If a sample value of 0</tt> <br><tt>is encounter.cgied by a DOC oscillator, the oscillator will immediately halt</tt> <br><tt>and not produce any more sound. The DOC additionally has an 8-bit volume</tt> <br><tt>register for each oscillator, with a linear slope. The dynamic range of the</tt> <br><tt>DOC (the 'space' between the softest and loudest sounds it can produce) is</tt> <br><tt>approximately 42 dB, or about on par with an average cassette tape.</tt> <p><tt> Each oscillator has it's own 16 bit frequency register, ranging from 0</tt> <br><tt>to 65535. In a normal DOC configuration, each step of the frequency register</tt> <br><tt>increases the play rate by 51 Hz, and computing the maximum theoretical play</tt> <br><tt>rate is left as an exercise for the student. :)</tt> <p><tt> When oscillators are paired to create generators, there are 4 possible</tt> <br><tt>modes:</tt> <p><tt>* Free-run: the oscillator simply plays the waveform and stops. No</tt> <br><tt> interaction with it's 'twin' occurs.</tt> <br><tt>* Swap: Only one oscillator of the pair is active at a time. When</tt> <br><tt> one stops, the other immediately starts.</tt> <br><tt>* Loop: The oscillator simply plays the waveform and if it hits the</tt> <br><tt> end without encounter.cgiing a zero, it starts over at the</tt> <br><tt> beginning.</tt> <br><tt>* Sync/AM: One oscillator of the pair modulates the volume of the</tt> <br><tt> other with the waveform it's playing. Not commonly used.</tt> <p><tt> Oscillators play waves stored in up to 128k of DRAM. The Ensoniq has</tt> <br><tt>it's own memory refresh system. Note that Apple only supplies 64k of</tt> <br><tt>DRAM for the DOC (this is known as the DOC RAM).</tt> <p><tt> The output of an oscillator can be directed to any one of 16 possible</tt> <br><tt>channels. Apple only makes 8 channels avalible via the 3 bits on the sound</tt> <br><tt>expansion molex connector, and all current stereo cards limit this to 1 bit,</tt> <br><tt>or two channels.</tt> <br><tt>_________________________________________________________________</tt> <br> <p><tt>About IIgs Stereo Cards</tt> <br> <p><tt>Mfr Name Notes</tt> <br><tt>--- ---- -----</tt> <br><tt>MDIdeas SuperSonic First IIgs stereo card. Not very well</tt> <br><tt> constructed, but sounds nice.</tt> <br><tt> Digitizer option is pretty good.</tt> <p><tt>MDIdeas Digitizer Pro Daughterboard for SuperSonic, but also</tt> <br><tt> takes up another slot in your GS. Pretty</tt> <br><tt> good, but very few were sold.</tt> <p><tt>Applied GStereo I've never used one; included for</tt> <br><tt>Ingenuity completeness.</tt> <p><tt>Applied FutureSound Most advanced card made. Includes</tt> <br><tt>Visions sophisticated noise reduction,</tt> <br><tt> coprocessor, and timing generator for</tt> <br><tt> ultimate control of sampling rates.</tt> <p><tt>Applied Sonic Blaster Generally poor to average card; bad</tt> <br><tt>Engineering decision to use non-shielded ribbon</tt> <br><tt> cable results in hissier than average</tt> <br><tt> output and digitizing.</tt> <p><tt>Applied Audio Animator The one they got right. Has digitizing</tt> <br><tt>Engineering circuitry external to the GS itself to</tt> <br><tt> avoid noise, plus a MIDI interface.</tt> <p><tt>Econ Tech. SoundMeister Generally above average quality. Nothing</tt> <br><tt> much to say. Pro version with direct-to-</tt> <br><tt> harddisk recording cancelled.</tt> <br><tt>_________________________________________________________________</tt> <br> <br> <p><tt>What about them other machines?</tt> <p><tt> Here's a rundown of sound on other computers...</tt> <br> <p><tt> Wavetable</tt> <br><tt>Computer/Card voices WT bits FM voices Stereo? Digitize?</tt> <br><tt>--------------------------------------------------------------------</tt> <br><tt>Apple IIgs 32 8 None Yes(4) Yes 8</tt> <br><tt>Soundblaster 1 8 11 No Yes 8(4)</tt> <br><tt> Pro 2 8 20 Yes Yes 8</tt> <br><tt> 16 2 16 20 Yes Yes 16</tt> <br><tt> 16 AWE32 32 16 20 Yes Yes 16</tt> <br><tt>Pro Audio</tt> <br><tt> Spectrum 16 2 16 20 Yes Yes 16</tt> <br><tt>Gravis</tt> <br><tt> UltraSound 32 8/16 None(2) Yes Yes 16(4)</tt> <br><tt> UltraSound Max 32 8/16 None(2) Yes Yes 16</tt> <br><tt> UltraSound PnP 32 8/16 None(2) Yes Yes 16(11)</tt> <br><tt>Logitech</tt> <br><tt> SoundMan Wave 20 16 22 Yes Yes 16</tt> <br><tt>Commodore</tt> <br><tt> Amiga (all) 4 8 None Yes Yes 8(4)</tt> <br><tt>Mac</tt> <br><tt> non AV, 0x0 4 8 None Yes(3) Yes 8(4)</tt> <br><tt> AV 0x0 Infinite(1) 8/16(10) Infinite(1) Yes Yes 16</tt> <br><tt> PowerPC 2 16 None Yes Yes 16</tt> <br><tt> AV PowerPC Infinite(9) 8/16(10) Infinite(9) Yes Yes 16</tt> <br> <br> <br> <p><tt> Wavetable Other</tt> <br><tt>Game Machine voices WT bits FM voices voices Stereo?</tt> <br><tt>--------------------------------------------------------------------</tt> <br><tt>Atari 2600 0 0 0 2 No</tt> <br><tt>Intellivision 0 0 0 4(8) No</tt> <br><tt>Nintendo Ent.</tt> <br><tt> System 1(5) 8 4 0 No</tt> <br><tt>Sega Genesis 1(5) 8 6 0 Yes</tt> <br><tt>Sega CD 3(7) 8/16(7) 6 0 Yes</tt> <br><tt>Super NES 8 12(6) 0 0 Yes</tt> <br><tt>Sega Saturn 32(12) 8/16 32(12) 0 Yes</tt> <br> <br> <p><tt>Notes:</tt> <p><tt>"Wavetable" as used here means "a channel capable of playing back a</tt> <br><tt>digitized waveform". This is NOT the generally musically accepted meaning of</tt> <br><tt>the term, but it IS how it is commonly used when referring to computer sound</tt> <br><tt>boards.</tt> <p><tt>"8/16" for WT playback bits means the chip is capable of directly processing</tt> <br><tt>8-bit or 16-bit samples without conversion (the GUS's GF1 chip and the AV</tt> <br><tt>Mac's DSP chip obviously fit these criteria).</tt> <p><tt>1- The AV Mac's DSP chip can theoretically mix an infinite number of</tt> <br><tt>wavetable voices or synthesize an infinite number of FM voices. However,</tt> <br><tt>this is limited in practice by the speed of the chip and any other things</tt> <br><tt>you have it doing (voice recognition, modem replacement, etc).</tt> <p><tt>2- The Gravis UltraSound can emulate FM synthesis in software.</tt> <p><tt>3- Macs before the Mac II were mono-only.</tt> <p><tt>4- This requires additional hardware.</tt> <p><tt>5- The Genesis and NES's wavetable channel is pretty hackish, and not very</tt> <br><tt>high quality; nonetheless it works for speech.</tt> <p><tt>6- The SNES's sound chip accepts 12 bit samples which have been ADPCM</tt> <br><tt>compressed (the same type method as ACE on the GS).</tt> <p><tt>7- The Sega CD has two channels of 44.1khz stereo 16-bit CD audio in</tt> <br><tt>addition to the capabilities of the Genesis.</tt> <p><tt>8- The Intellivision uses the General Instruments AY-3-8192 chip found on</tt> <br><tt>Apple II boards such as the Phasor and Mockingboard. This provides three</tt> <br><tt>tones and one percussive noise at once.</tt> <p><tt>9- The PowerPC AV Macs have no dedicated DSP chip; they use the main CPU,</tt> <br><tt>which can cause application performance degradation (see also note 1).</tt> <p><tt>10-AV Macs of both CPU types have a 2-channel 16-bit CODEC to actually</tt> <br><tt>reproduce the audio, but the DSP or 60x chip are capable of conversion.</tt> <p><tt>11-The Gravis UltraSound PnP specs also apply to other AMD InterWave-chip</tt> <br><tt>based boards such as the Reveal WavExtreme 32.</tt> <p><tt>12-The Saturn's 32 voices can each be set to either waveform playback or FM.</tt> <br><tt>FM is not limited to sine waves as on older chips, however.</tt> <br> <p><tt>__________________________________________________________________________</tt> <br> <p><tt>Copyright (c) 1993-97 Ian Schmidt and Cygnix Development. Contents may be</tt> <br><tt>freely distributed as long as no editing occurs without permission, and no</tt> <br><tt>money is exchanged. Exceptions are hereby explicitly provided for Joe</tt> <br><tt>Kohn's Shareware Solutions II, the services America Online, GEnie, and</tt> <br><tt>Delphi, and for user groups everywhere. The Apple II: It just keeps going</tt> <br><tt>and going and going....</tt> <p><tt>Oh, and for the benefit of Marc:</tt> <br><tt>-30-</tt> <p><tt>Ian Schmidt / irsman@iastate.edu / irsman@cs.iastate.edu / BAZ IS RIGHT!!!</tt> <p><b><a href="#top">to top</a></b> <br> </body> </html>