Interactive Music: Merging Quality
with Effectiveness

By Alexander Brandon
Straylight Productions
Gamasutra
March 27, 1998
Vol. 2, Issue 13

Interactive Music
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Video game music that changes depending on the player's actions or surroundings, known also as "interactive music" to the hip marketing people, isn't a new phenomenon. Back in the 1980s a game called Popeye had a frantic theme play when hearts that the muscle-bound cartoon character was supposed to catch would slowly slide into the water at the bottom of the screen. More recently the computer hit System Shock by Origin Systems had theme music for different areas in each level that fit each area like a glove, enhancing the experience far more than a single theme for each level. Now the question on most composers' minds isn't just how to make game music interactive, but how to make it more realistic and, most of all, exciting. For the sake of both layman and veteran, the purpose of this article is to lay down what is being done in the industry on both the hardware and game development fronts, and why the mass confusion developers and hardware suppliers seem to be experiencing is real. Developers want to create interactive music, but how, what systems are the best to use, and with what hardware? We'll try to answer these questions as well.

Computer Music Authoring Systems/Tools

For developers who know what they're dealing with, the first question to address is "what systems are there to use?" The three most widely used ways of composing game music are General MIDI / XG / onboard wavetable synth format, which uses the built in synthesizers on soundcards, Redbook audio, which simply streams recorded music from a CD through a digital chipset, and digital modules, aka "MODs", which take custom built samples and play them back through a similar chipset as Redbook. There are advantages and disadvantages to all three formats, especially when used interactively.

MIDI / Soundcard Synth

Using the onboard synth of a soundcard gives an application more memory allocation to visual elements such as 3d processing, script manipulation, and special effects. Since samples are stored on the soundcard itself, all that is needed is information to control the samples, sometimes not exceeding 20k per music file. Onboard synths, which are controlled via an external controller or anything that the user wishes to use to input the music during the composition process, can also fade tracks in and out and even change the music itself interactively. The files can also be created in many different programs, through sequencing programs like "CakeWalk Pro" by Twelve Tone Systems, or even a simple freeware MIDI sequencer.

The biggest drawback to this method is that onboard synths in soundcards such as the "SoundBlaster AWE64" by Creative Labs are essentially scaled down versions of real synthesizers, and don't provide grade-A music quality. For instance, if you took a high end synthesizer such as a Korg M1, with a cost of over $1000, and brought the price down to less than $100, you'd have a pretty weak synth. Redbook audio musicians use up to tens of thousands of dollars (or more) worth of instruments and equipment, so the quality of music coming from something at a fraction of that cost will be relatively lower. Just as an example, the latest onboard synths do not feature extensive effects sections with more than 3 or 4 effects groups such as echo, reverb, distortion, etc. The samples themselves are smaller than those found on professional synthesizers and tone modules, giving them their distinctive mediocre, flat sound that we all hear played on thousands of personal web pages. That isn't to say that consumer cards such as the AWE64 aren't excellent cards in many other ways, they just can't compete with a professional orchestra in terms of sound quality and realism. Creative Labs is trying to answer this problem with "SoundFont" technology, which allows the user to create their own samples, but their soundbank (group of instruments) size is limited to 512k for owners of the AWE64 Value Edition. Most professional synths come with at least 8-12 megabytes of sample information. Yamaha is countering this with their "SW Waveforce" series of cards, and we'll discuss the features of these new cards shortly.

Redbook Audio

Redbook audio, on the other hand, can be a professional orchestra, a group of synthesizers, or an alternative band. Any music at all can be recorded and streamed directly into the game, which gives it the quality of a movie soundtrack. However, the music itself cannot change (obviously, its been recorded) and tracks cannot overlap or be played simultaneously as using wavetable synthesis can do.

The compromise between the high quality of Redbook and the small size and flexibility of onboard synth development is digital modules (MODs). Many composers have often cast a disapproving eye on MOD music, since methods of composing MODs are complicated and extremely "non user friendly." While an onboard synth composer might use his MIDI (musical instrument digital interface) keyboard to play and sequence tracks, the MOD composer uses a "tracker," which is a piano roll, computer keyboard input based system of composition. Once the initial learning curve is bounded over, however, the power of MOD, or "tracked" music, becomes instantly appealing.

Music Authoring Systems/Tools (cont.): Digital Modules (MODs)  Next Page