Sound in Video Games
  How do they make it?
    How do we use it?
by Josh Martin
[Appeared in the October/November 1983 issue of "Video Games Player"]
                        
                        
        What is a video game without sound? Your ears tell you if your guns
have fired, whether you hit your target and when the monsters are coming. 
There are trumpets of victory and the agony of defeat, not to mention other 
nifty squeaks, squeals, screams and, on occasion, voices. Sound is the unsung
hero of the video game.
        Somewhere in the wilds of New Jersey is a group of engineers and 
technicians, gathered like scientists, thinking up sounds you have never 
heard, for games that no one has ever played. This is the design team of 
Activision. Elaborate precautions are taken to ensure secrecy at this lab. 
Even a simple phone call from the outside must get special clearance from a 
separate office in New York. Company officials strictly limit outside contact 
for the engineers and technicians: "They don't disturb them for any reason,"
said an amazed secretary. "They're serious, too."                     
        In this quiet atmosphere, designers work on sound effects for 
explosions, rockets and symphony orchestras. As long as there have been video 
games, there have been sounds to listen to while playing. Of course, back in 
the early days, those sounds were pretty much limited to the beep of a moving 
cursor as it hit the edge of a playing field.                    
        Now, after years spent developing graphics, the Activision game 
designers and others are going to work on soundtracks, to make what you hear 
as good as what you see. The results are audible in home and arcade games: 
better music, realistic action sounds, and high-quality voice synthesis.
        Case in point: Pong, admittedly a pioneer game, used an effect that
sounded more like a beeping radar screen than the bouncing tennis ball it was 
supposed to represent. But the ball in Activision's Tennis (Atari VCS) 
generates authentic "thwacks" when it's whacked with a racket.
        In the arcades, sound has also been evolving for the better. Who 
could forget the gimmicky explosions in Space Invaders> They sounded more 
like little electronic pops--hardly what you'd expect from an exploding space 
ship. In Zaxxon, however, the devastation done to enemy fuel tanks and 
rockets is often realistic enough to make you want to dive for cover. (And 
let's not forget Sub-Roc, whose designers didn't forget impressive sound 
effects when dreaming up those razzle-dazzle 3-D graphics.)
        Activision's Dolphin demonstrates the most enterprising and 
innovative exploitation of sound so far. Many games warn of impending danger 
with an appropriately timed noise, but this one helps out with varying sonic 
cues--differences in the sound's pitch signal the safest direction in which 
to swim to avoid the killer octopus. Designing such effects is obviously even 
more challenging--and sometimes as much fun--as playing the game itself, 
according to some programmers.
        Garry Kitchen is one of three brothers who design games for 
Activision. Sound has become a new challenge for this video veteran. "I 
don't think I've done as much with sound as I can," he says. "It's still
mostly support for graphics."
        "You put sound in and take it out as you design your game," Kitchen 
adds. "You have to consider that the sound must fit into the memory that's 
available. It's a delicate balance between making things good and making them 
fit."
        For Mark Turmell, a game designer with Sirius (Beer Run, Sneakers, 
Turmoil, Fast Eddie) soundtracks are the result of a lot of testing. "It's an
intricate process," he says. "Sounds are made up of numbers in a computer. It 
often starts on a random basis."
        Making that random sound perfect takes time, experience, and money.
Suzanne Ciani, the musician and electronic effects specialist whose work can
be heard in Bally's Xenon pinball game, works 12 to 18 hours a day, with an 
array of 28 synthesizers. This custom-built equipment is expensive--one 
synthesizer can cost $60,000--and so is Ciani's talent. A Ciani soundtrack 
will cost as much as $25,000.
        Even the shortest soundtrack can take weeks or even months to 
produce. In Turmell's Turmoil, a Fox game introduced last November, there is 
a tune at the end of play which is totally mathematically generated and 
synthesized. According to Turmell, the music, which lasts 35 seconds, took 
over 70 hours of studio time to produce.
        Sound is broken down into several categories. First there is real 
sound which you can hear in your everyday experience, like a car horn or a 
dog barking. Sometimes, soundtracks will use tapes with real sounds. But more 
often, the sounds you hear while playing a video game are mathematically 
generated and measured by frequency. Synthesized sound, created by machines, 
registers as numbers on a dial in a game designer's studio.
        Game designers consider three types of synthesized sound: high 
frequency, low frequency, and white noise. White noise is created with a 
random number generator, switching frequencies very fast. It is often used 
for sounds like explosions or footsteps. Game designers who work on 
soundtracks soon become versed in frequency numberd and the sounds they 
represent. "I can pretty much tell what a series of numbers will sound
like," says Kitchen.
        The sophistieated use of sound in Q*bert provides indication of 
where soundtracks are going. Sound is used to give the characters personality. 
It is also, in its own way, communicating to players. "Q*bert is not trying 
to say anything understandable." says a Gottlieb programmer who helped 
develop the game. "The sound is used to provide clues and enhance effects. It 
gives you a clue about what's coming up in the game."
        There are limits to sound. While home games can use better quality, 
arcade games will continue to rely on graphics. As one sound programmer put 
it, "In a war environment like the arcades, it's hard to hear anything." So 
in an arcade game, explosions are just about the only sound that matters, 
because they are about the only noises which can rise above the din.
        Ed Rotberg, who worked on designing Asteroids and Battlezone, says 
the arcade environment doesn't allow for sophisticatted sounds like voice 
synthesis or player-produced music. "Arcade applications have to wait until 
we have total environment games," he says. Such games would be able to deal 
with four senses: sight, hearing, touch and smell.
        For now, however, the main goal is realism: a car crash in which you 
feel the twisted metal, a rocket that makes the hair on your neck stand up, a 
bomb explosion that rocks you back from the controls. As the graphics and 
sounds become more realistic, we care more about winning the game. You have 
to rescue that human, not just some blip on a screen. There is more riding 
on it. And if you think today's games sound tough, wait until next year!

SIDEBAR: How do you make a sound?

        There are hard sounds and soft sounds, representing different fre-
quencies and sound-wave patterns. Hard sound waves are jagged and look
like sawteeth. As a number pattern (which is how sound programmers create it), 
a hard sound might read 1,2,3,1,2,3. This pattern can be used to create a 
motorcycle noise.
        Another type of hard sound is created by square-wave systems, which 
sets up number patterns like 1,1,3,3,1,1,3,3. The visual pattern is like a 
light being turned on and off. A thunder clap can be made by using square-wave 
noise.
        A soft sound creates a wiggly sound wave that can be seen in a number
pattern like 1,2,3,2,1,2,3,2. This is used to simulate footsteps or gentle
noises.
        In Q*bert, the sound programmer started at a computer terminal by 
typing in numbers, which were turned into electrical power in a Digital 
Analogue Converter (DAC). A DAC can produce up to 256 different voltage 
levels, so the programmer can type in numbers ranging in size from 1 to 256.
Then the programmer determined the speed at which the numbers change, which 
is the speed of running through different voltage levels. This determines the 
resulting sound frequency.
        Howard Delman, a former hardware designer with Atari who was 
responsible for Asteroids, explains how an explosion is created:
        "An explosion is a random selection of sound frequencies. It starts 
off very loud and then falls off. The way to make one explosion different 
from another is to select different frequencies. The sounds are all made by
selecting a group of frequencies using a Random Noise Generator.
        "The Random Noise Generator circuit creates a wide spectrum of 
frequencies simultaneously, creating a hissing sound--'white' noise. Another
circuit selectively eliminates certain frequencies; it is a controllable 
filter. And a third circuit controls the volume of the signal. When an 
explosion is started, this third circuit allows the frequency to pass through 
at full volume, and then very quickly decays the amplitude. We can restart 
the sound, however, to make a comp]ex explosion."
        An explosion for one of the big rocks in Asteroids uses lower 
frequencies, hence the rumbling noise. A spaceship uses higher frequencies. 
The only software programming involves four choices of explosion frequency 
circuits, to cover the different size rocks and the spaceships. By comparison,
each sound you hear in Q*bert is a different software program, and there are 
about 25 small programs in the game.

[Scanned and edited by Dennis Brown, dgbrown (at) pixesthesia (dot) com]