Audio Used as Feedback

A description of audio used as feedback to the player in the game 'Portal 2'.

The video linked above provides an example of multiple layers of audio feedback to the player.

I am using the term 'audio feedback' to refer to sound that, "helps the player feel his actions have an effect..." (Russell, 2012)

The objective is to direct the laser through the four lamps on the floor of the map. Directing the laser through each of the lamps will trigger an ascending tone. This kind of ascending sound is commonly associated with switching on electronic or mechanical equipment such as engines or computers. This tells the player that a switch has been engaged.

The other elements of audio feedback need to be contrasted to the rest of the in- game audio. Portal 2 is set in a deserted and delapidated scientific research centre. The base ambience in the game, as evidenced in the video, consists of the low humming of fans and electronics and the movement of air. Other sounds that should contain higher frequency content such as water drops have the high end noticeably filtered out through the high frequency roll off of the reverb. There is little high frequency audio.

Activating a lamp using the laser triggers a musical cue. The music that engages contrasts against the base audio in that it provides some higher frequencies with a modulated delay affected rhythmic synthesizer that plays major and suspended chords. The presence of music is in itself a form of positive feedback to the player in a previously sparse audio environment. The positive sound of the major chords (Cook, 2006) rewards and encourages the player to turn all of the switches on.

Turning on more switches adds an extra layer to the music in the form of a string pad, emphasising the objective of engaging all of the switches. The string pad provides even higher frequency content by playing two octaves higher than the rhythmic

synthesizer. This brightens the sound even more and fills up the higher end of the audio

spectrum.

The instruments used in the music provide bright and undistorted sounds. They are much closer to pure tones than the sound effects created by the 'carry object' function of the gun or the laser which is used to trigger the music. Both contain much more inharmonic content. The purer tones suggest less aggression and emphasise to the player the idea that the music is a result of a good action.

While the music is designed to invoke a positive response from the player and could reasonably be described as both a reward and feedback, the latter description is more appropriate because the music is both activated with the lamps and localised to the

lamps. This reinforces to the player the fact that the activated lamp is part of the objective

in the map. The attenuation is affected by the player proximity to an activated lamp and the position of the music in the stereo image follows the position of the nearest activated lamp in relation to the player. This added method of audio feedback draws the player's attention to this key object providing further encouragement to activate the remaining switches. The music is therefore used as informative feedback to

the player that serves a secondary function of including an element of reward.

Russell, D (2012). Video Game Audio: Diagesis Theory.[online]Available at: http://devmag.org.za/2012/04/19/video-game-audio-diegesis-theory-2/ [Accessed 3rd October 2016]

Bakker, D.R. & Martin, F.H. (2015) Musical chords and emotion: Major and minor triads are processed for emotion. Cogn Affect Behav Neurosci, Issue 1, pp. 15- 31doi:10.3758/s13415-014-0309-4

Cook, N.D. (2006) A Psychophysical Explanation for Why Major Chords are “Bright” and Minor Chords are “Dark”. Proceedings of The First International Workshop on Kansei [online]Available at: http://www.psycho.hes.kyushu- u.ac.jp/~lab_miura/Kansei/Workshop/proceedings/O-205.pdf [Accessed on 3rd October 2016]