Producing Game Audio

In Listening to the Game – A Brief History of Game Audio we briefly considered the history of in-game audio. In this post, I’d like to look at how audio design and production fits in to the game development process.

The following two articles from the IGDA Casual Games Quarterly were written by a game and interactive media audio designer in a company that handles outsourced audio design requirements (Somatone interactive audio). The articles are intended to help other members of a game development team understand what’s involved in audio design, and tell them what they need to know in order to have sensible – and hopefully productive – conversations with their audio developers…

• Improving Communication with Your Sound Designer, Part 1 by Kane Minkus, IGDA Casual Games Quarterly, vol. 2(2) 2007.
• Improving Communication with Your Sound Designer, Part 2 by Kane Minkus, IGDA Casual Games Quarterly, vol. 2(3) 2008.

Based on a reading of Improving Communication with Your Sound Designer, Part 1, or otherwise:

• what is the role of a sound designer in a game design team, compared to a composer? Does this view differ in the games industry compared to other creative industries?
• what tools is the sound designer likely to use to in the audio production process?
• what are the differences between composers and sound designers in an interactive media production team? At one points are the involved in the game design process? (If you put together your own game development process diagram having read The Process of Game Creation & the Game Design Document, modify your diagram if necessary to include the roles of sound designer and composer?
• what properties of the audio signal are dealt with when the audio is “mixed”?

The second article addresses the concepts involved in audio design at a more technical level. If you are particularly interested in audio design, it’s worth reading… but for the purposes of Digital Worlds, I think it’s a little too involved for now!

Knowing what you know about the game design process, you might expect there to be a part of the game design document dedicated to audio design. Read the first part of Design With Music In Mind: A Guide to Adaptive Audio for Game Designers. What are the key questions that must be addressed by the ‘music design’ for a game? As well as music design, what other elements of audio design need to be addressed by a complete audio design statement? (You may find the first part of Finishing the Maze – Adding Background Music, as well as the comments, relevant here.)

Finishing the Maze – Adding Background Music

To round off the tidying up of the maze game, it’s probably worth revisiting the aural dimension. Sound design is a major factor in the early success or otherwise of many computer games (none more so than audiosurf – fancy riding Song 2? Woo hoo…;-) and one that we have only paid passing reference to in the design of the maze game so far.

There are three main components to the sound design of a game.

Firstly, there is the background musical soundtrack. In many driving games, this may be contextualised by an in-car radio player (the Grand Theft Auto series has a prime example of this), but often the soundtrack has more in common with the background music of a film. The way that the background music can be used to set the emotional tone of a scene and its potential effect on setting the mood of the player should not be underestimated.

The second component relates to sound corresponding to foreground events. The player character saying “ouch” if attacked by a monster, or an audible reward to complement the collection of a treasure item.

These sounds are typically triggered by actions performed in response to a particular event being raised by object interactions within the game, in contrast to the background music which plays ‘just anyway’.

The third component is incidental background noise. This corresponds to the everyday background noise that ‘thickens’ a scene and adds depth and character to it.

Hopefully, you have already added some sounds to your game, for example to reinforce the collection of a diamond, the capture of the player character by a monster, the unlocking of a door, or the completion of a room by reaching the door.

(As well as the sound files in the game Maker maze tutorial folder, you can find additional sounds on the Game Maker site: Game Maker resources: sounds.)

Adding background music

To complete the game, we are going to add some background music.

There are two ways of doing this: use a MIDI file, or use an audio file.

• MIDI background track: MIDI (“Musical Instrument Digital Interface”) is a protocol (that is, a conventional language) that was originally used to connect physical music synthesizers (that is, digital music keyboards!) together. MIDI is increasingly used to ‘program’ music that is played by an audio synthesiser to create a musical background track. A MIDI file essentially instructs a synthesizer (sound generator) what sound to play, when, and for how long. Most computers today have a sound card that is capable of generating sounds from a MIDI file.
• audio background track: an audio file is just a recording of a sound. Game maker can play two different sorts of audio file: WAV files (simple digital recordings of of sound); and MP3 files (compressed audio files; that is, audio files that have been digitally manipulated so as to take up less memory space in a computer.)

Audio files are best used for foreground sounds – sounds used to denote a collision event within the game for example. WAV files, whilst being larger than MP3 files, can be played directly. In comparison, MP3 files must be uncompressed before they are played, which takes up computer processor time (time which may be better spent actually managing the computer game, looking for collision events and keyboard button presses, for example).

The smaller MIDI files are better suited to ongoing background music. Often, a computer’s audio card will manage the playback of the sound from the MIDI file.

To load music in to the game, select Create Sound from the Resources menu.

To use a MIDI file for the background music, select ‘Background music’; to play an MP3 or WAV music file, select the ‘Use multimedia player’ option.

The background music should be started from the Create event of a spriteless controller object added to the room, and set to loop.

If you do use a music file that his played via a multimedia player, you should preload it so that loading it does not slow the game down as once it is being played. However, for large audio files, the memory requirements of preloading the audio file may affect the performance of the game.

When using audio files you should take care that copyright licenses are not being infringed, particularly if you intend to distribute the game or even share it with other people.