TweetFollow Us on Twitter

Sound 101
Volume Number:9
Issue Number:3
Column Tag:C Workshop

Related Info: Sound Manager

Sound 101

Evolution of the Mac voice

By Iggi Monahelis, Pleasanton, California

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

About the author

Iggi Monahelis is a programmer who bought his first Mac as soon as he could back in 1984. He is the principal designer and co-author of “Read My Lips”, the sound annotation utility for the Macintosh.


This is an introductory article, hence the name Sound 101, dealing with basic recording and playback of sounds on the Macintosh. It explains the required steps to be taken in order to digitize sounds using a microphone, in two different sound formats, and play them back. It is a good stepping stone for someone who has little or no knowledge of how to do these things in a program on the Macintosh. As a matter of fact, one can probably copy the routines given in the article, and use them in their own program without a lot of modifications.

Ancient History

The Macintosh has had the capability of producing sounds since day one. The famous introduction of the Macintosh back in 1984 used sound, in the form of digitized speech, to allow the Mac to introduce itself. Inside Macintosh back then had a chapter on the Sound Driver with just a few routines, literally StartSound, StopSound and SoundDone, that allowed the programmer to control the Sound Driver. The Sound Driver produced sound using three different sound synthesizers:

1) the four-tone synthesizer, used to make simple harmonic tones, with up to four “voices” producing sound simultaneously. Hence the name four-tone.

2) the square-wave synthesizer, used to produce sounds such as beeps.

3) the free-form synthesizer, used to produce complex sounds, music and speech.

You had to “describe” the sound to the Driver as a waveform, basically fill a buffer with a bunch of numbers, and tell the Sound Driver to start producing noise based on these numbers. Very primitive.

Middle Ages

With the introduction of the Macintosh II class of machines, the Sound Driver had graduated to the Sound Manager. It was indeed a graduation because several innovations had taken place:

1) The hardware now included a new sound chip which freed the machine’s processor from doing all the work.

2) The introduction of sound resources. Sound resources can “contain” any sound you can imagine, from a simple beep sound to digital recordings of CD’s. And because they are resources, in the Macintosh sense of the word, you can work with them using standard Resource Manager calls. To play a sound resource all you have to do is load it and pass the handle to the resource to the SndPlay routine.

3) The Sound Manager now has seven routines to allow you to work with sound.

To produce sound, commands are sent to a synthesizer, as was the case with the Sound Driver. The Sound Manager uses a queue to send these commands to a synthesizer, these queues are called channels. To make complex sounds, many sounds may need to be produced simultaneously. For this reason several synthesizers can have multiple channels.

The new Sound Manager uses three synthesizers to produce sound:

1) the wave-table synth, lets you supply a wave table that describes the sound. This lets you produce more complex sounds, also it lets you play multiple sounds simultaneously by opening several channels. It corresponds to the old four-tone synth with four channels open.

2) the note synth, used to produce simple sounds, such as a note. The note synth can produce only one note at a time. It compares to the old square-wave synth from the Sound Driver.

3) the sampled sound synth, used to play digitally recorded sounds. In this case instead of passing the note or a wave table describing the sound you want played, you pass a buffer that contains samples of the sound to be played. This synth compares to the old free-form synth from the Sound Driver.

Despite the innovations that came with the Mac II and the graduation of the Sound Driver to a Manager, it was still difficult to digitize sounds using System software. It was easy once you had a sound resource to play it and several programs, mostly shareware, were created to play sound resources. Farallon came out with the MacRecorder® sound digitizer which allowed you to digitize sounds using the software that came with it, but still you could not do that in your own program without writing a lot of code yourself.


With the introduction of the Macintosh IIsi and Macintosh LC, Apple for the first time included a built-in microphone with the Macintosh. System software versions 6.0.7 and later have a new and improved version of the Sound Manager. The Sound Manager chapter goes from 32 pages to 114 pages. This latest version introduces a whole slew of new features, some of which are:

1) There are now routines to record sounds using the built-in microphones, or any third party microphone with the appropriate driver for Macs that do not come with a microphone.

2) One can record either sound resources (‘snd ‘), or record directly to a file on disk in a format known as: Audio Interchange File Format (AIFF).

3) There are routines that allow for compressing and decompressing of sound data.

4) There are now routines that allow for the playing of sounds directly from disk. So one does not have to load all of the sound in memory in order to play it.

5) Customization galore. Besides the high-level routines for recording and playback there are low-level routines so that one could customize the way recording and playback is done.

Writing the program

It is always easier to start with a basic program, understand it, and then expand on it. The Sound 101 program is just such a program for learning the basics about recording and playing sounds. The program can record and play 'snd ' and AIFF sound files. It also allows for the selection of sound quality.

Here goes the code with explanations...

© 1992 Praxitel, Inc. and Iggi Monahelis

This is the “main” for the Sound 101 project.  It has the minimum stuff 
to get a mac
program going.  Basically, it does all the required mac initializations, 
sets up the menu
bar, and then gets and processes events.

#include “Sound101.h”

extern int  gDestroyChannel;
extern SndChannelPtr gSndChan;
extern short     gFRefNum;
extern long gQuality;



This is the main routine for the Sound 101 application, it does all the 
Mac initializations.
Then calls the EventLoop procedure to get and process events.

void main(void)
 InitGraf((Ptr) &thePort );

 EventLoop();    /* Do event processing until user quits */




Set up the menu bar for the Sound 101 application
void SetUpMenus(void)
 MenuHandle myMenu;
 myMenu = GetMenu(mApple);
 AddResMenu( myMenu, ‘DRVR’ );
 InsertMenu( myMenu, 0 );
 InsertMenu(GetMenu(mFile), 0) ;



Event handling for the Sound 101 application.
Get events forever, and handle them by calling DoEvent.
void EventLoop(void)

 do {
 gotEvent = WaitNextEvent(everyEvent, &event, 50, 0);
 if ( gotEvent ) {
 /* if we are done with the sound, dispose the sound 
    channel and close the sound file. */     
 if ( gDestroyChannel ) { 
 OSErr  myErr;
 if (gSndChan)
 myErr = SndDisposeChannel( gSndChan, TRUE);
 if (gFRefNum)
 myErr = FSClose(gFRefNum);
 /* make sure we do it only once! */
 gDestroyChannel = FALSE;
 gSndChan = 0;
 gFRefNum = 0;
 } while ( true ); /* loop forever */
} /*EventLoop*/



Determine the event type and dispatch accordingly
void DoEvent(EventRecord *event)
 short  part, err;
 char   key;

 switch ( event->what ) {
 case nullEvent:
 case mouseDown:
 part = FindWindow(event->where, &window);
 switch ( part ) {
 case inMenuBar:
 /* process a mouse menu command */
 case inSysWindow:
 /* let the system handle the mouseDown */
 SystemClick(event, window);
 case inContent:
 case inDrag:                
 case inGoAway:
 case inGrow:
 case inZoomIn:
 case inZoomOut:
 case keyDown:
 case autoKey:
 /* check for menukey equivalents */
 key = event->message & charCodeMask;
 if ( event->modifiers & cmdKey ) {
 /* Command key down */
 /* if command-period was pressed, set our global
    to clean up the sound channel and close the
    open sound file. */
 if ( key == ‘.’ )
 /* command period was pressed */
 gDestroyChannel = TRUE;
 case activateEvt:
 case updateEvt:
} /*DoEvent*/



Handles menu selections for the Sound 101 application
void DoMenuCommand(long menuResult)
 short  menuID, menuItem;
 short  itemHit, daRefNum;
 Str255 daName;

 menuID = HiWord(menuResult);
 menuItem = LoWord(menuResult);
 switch ( menuID ) {
 case mApple:
 switch ( menuItem ) {
 case iAbout: {  /* bring up the About box */
 OSErr  err;
 Rect   tempRect;
 aboutDlg = GetNewDialog(128, nil, (WindowPtr) -1);
 if ( aboutDlg ) {
 /* Open a dialog box */
 SelectWindow(aboutDlg);  /* Lets see it */
 while (TRUE) {
 ModalDialog(NULL, &itemHit);
 if ( itemHit == 1 )

 /* all non-About items in this menu are DAs */
 GetItem(GetMHandle(mApple), menuItem, daName);
 daRefNum = OpenDeskAcc(daName);
 case mFile:
 switch ( menuItem ) {
 case iPlaySound:
 case iRecordsndSound:
 case iRecordAIFFSound:
 case iQuality:
 case iQuit:
 /* unhighlight what MenuSelect (or MenuKey) hilited */



Quit the app
void Terminate(void)
 /* exit if no cancellation */
} /*Terminate*/

Community Search:
MacTech Search:

Software Updates via MacUpdate

Opera 40.0.2308.90 - High-performance We...
Opera is a fast and secure browser trusted by millions of users. With the intuitive interface, Speed Dial and visual bookmarks for organizing favorite sites, news feature with fresh, relevant content... Read more
BetterTouchTool 1.93 - Customize Multi-T...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom... Read more
Backblaze - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac. With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Postbox 5.0.5 - Powerful and flexible em...
Postbox is a new email application that helps you organize your work life and get stuff done. It has all the elegance and simplicity of Apple Mail, but with more power and flexibility to manage even... Read more
Coda 2.5.19 - One-window Web development...
Coda is a powerful Web editor that puts everything in one place. An editor. Terminal. CSS. Files. With Coda 2, we went beyond expectations. With loads of new, much-requested features, a few surprises... Read more
Toast Titanium 15.1 - $99.99
Roxio Toast 15 Titanium, the leading DVD burner for Mac, makes burning even better, adding Roxio Secure Burn to protect your files on disc and USB in Mac- or Windows-compatible formats. Get more... Read more
Firetask 3.8.1 - Innovative task managem...
Firetask uniquely combines the advantages of classical priority-and-due-date-based task management with GTD. Stay focused and on top of your commitments - Firetask's "Today" view shows all relevant... Read more
Chromium 54.0.2840.71 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 54.0.2840.71: Release notes were unavailable... Read more
Chromium 54.0.2840.71 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 54.0.2840.71: Release notes were unavailable... Read more
Firetask 3.8.1 - Innovative task managem...
Firetask uniquely combines the advantages of classical priority-and-due-date-based task management with GTD. Stay focused and on top of your commitments - Firetask's "Today" view shows all relevant... Read more

Latest Forum Discussions

See All

WitchSpring2 (Games)
WitchSpring2 1.27 Device: iOS Universal Category: Games Price: $3.99, Version: 1.27 (iTunes) Description: This is the story of Luna, the Moonlight Witch as she sets out into the world. This is a sequel to Witch Spring. Witch Spring 2... | Read more »
Best Fiends Forever Guide: How to collec...
The fiendship in Seriously's hit Best Fiends has been upgraded this time around in Best Fiends Forever. It’s a fast-paced clicker with lots of color and style--kind of reminiscent of a ‘90s animal mascot game like Crash Bandicoot. The game... | Read more »
5 apps for the budding mixologist
Creating your own cocktails is something of an art form, requiring a knack for unique tastes and devising interesting combinations. It's easy to get started right in your own kitchen, though, even if you're a complete beginner. Try using one of... | Read more »
5 mobile strategy games to try when you...
Strategy enthusiasts everywhere are celebrating the release of Civilization VI this week, and so far everyone seems pretty satisfied with the first full release in the series since 2010. The series has always been about ultra-addictive gameplay... | Read more »
Popclaire talk to us about why The Virus...
Humanity has succumbed to a virus that’s spread throughout the world. Now the dead have risen with a hunger for human flesh, and all that remain are a few survivors. One of those survivors has just called you for help. That’s the plot in POPCLAIRE’... | Read more »
Oceans & Empires preview build sets...
Hugely ambitious sea battler Oceans & Empires is available to play in preview form now on Google Play - but download it quickly, as it’s setting sail away in just a few days. [Read more] | Read more »
Rusty Lake: Roots (Games)
Rusty Lake: Roots 1.1.4 Device: iOS Universal Category: Games Price: $2.99, Version: 1.1.4 (iTunes) Description: James Vanderboom's life drastically changes when he plants a special seed in the garden of the house he has inherited.... | Read more »
Flippy Bottle Extreme! and 3 other physi...
Flippy Bottle Extreme! takes on the bottle flipping craze with a bunch of increasingly tricky physics platforming puzzles. It's difficult and highly frustrating, but also addictive. When you begin to master the game, the sense of achievement is... | Read more »
Plants vs. Zombies Heroes guide: How to...
Plants vs. Zombies Heroes surprised us all, presenting a deep deck building experience. It's a great CCG that stands up well to the competition. There are a lot of CCGs vying for players' attention at the moment, but PvZ Heroes is definitely one... | Read more »
Arcane Online takes Online RPG’s to anot...
If you think that you need a desktop to enjoy high quality MMO gaming then Arcane Online hopes to prove you emphatically wrong. An epic fantasy Online RPG set in the land of Eldine, Arcane Online offers an abundance of features and content that... | Read more »

Price Scanner via

Apple’s Thursday “Hello Again” Event A Largel...
KGI Securities analyst Ming-Chi Kuo, who has a strong record of Apple hardware prediction accuracy, forecasts in a new note to investors released late last week that a long-overdue redo of the... Read more
12-inch Retina MacBooks on sale for $100 off...
Amazon has 2016 12″ Apple Retina MacBooks on sale for $100 off MSRP. Shipping is free: - 12″ 1.1GHz Silver Retina MacBook: $1199.99 $100 off MSRP - 12″ 1.1GHz Gold Retina MacBook: $1199.99 $100 off... Read more
Save up to $600 with Apple refurbished Mac Pr...
Apple has Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The following... Read more
PixelStyle Inexpensive Photo Editor For Mac W...
PixelStyle is an all-in-one Mac Photo Editor with a huge range of high-end filters including lighting, blurs, distortions, tilt-shift, shadows, glows and so forth. PixelStyle Photo Editor for Mac... Read more
13-inch MacBook Airs on sale for $100-$140 of...
B&H has 13″ MacBook Airs on sale for $100-$140 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only: - 13″ 1.6GHz/128GB MacBook Air (sku MMGF2LL/A): $899 $100 off... Read more
2.8GHz Mac mini available for $988, includes...
Adorama has the 2.8GHz Mac mini available for $988, $11 off MSRP, including a free copy of Apple’s 3-Year AppleCare Protection Plan. Shipping is free, and Adorama charges sales tax in NY & NJ... Read more
21-inch 3.1GHz 4K on sale for $1379, $120 off...
Adorama has the 21″ 3.1GHz 4K iMac on sale $1379.99. Shipping is free, and Adorama charges NY & NJ sales tax only. Their price is $120 off MSRP. To purchase an iMac at this price, you must first... Read more
Check Apple prices on any device with the iTr...
MacPrices is proud to offer readers a free iOS app (iPhones, iPads, & iPod touch) and Android app (Google Play and Amazon App Store) called iTracx, which allows you to glance at today’s lowest... Read more
Apple, Samsung, Lead J.D. Power Smartphone Sa...
Customer satisfaction is much higher among smartphone owners currently subscribing to full-service wireless carriers, compared with those purchasing service through a non-contract carrier, according... Read more
Select 9-inch Apple WiFi iPad Pros on sale fo...
B&H Photo has select 9.7″ Apple WiFi iPad Pros on sale for up to $50 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 9″ Space Gray 256GB WiFi iPad Pro: $799 $0 off... Read more

Jobs Board

*Apple* Retail - Multiple Positions- Napervi...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Security Data Analyst - *Apple* Information...
…data sources need to be collected to allow Information Security to better protect Apple employees and customers from a wide range of threats.Act as the subject Read more
*Apple* Retail - Multiple Positions (Multi-L...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions- New Yor...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions- Yonkers...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.