Perceived Quality in Game Audio - Game Sound Technology and Player Interaction: Concepts and Developments - page 169

Figure 4. Grey-scale screenshot of the game scenario

on the screen near the chimney, which served as
the source of the flying objects. Figure 4 shows
a screenshot of the game scenario.
A typical background music track for an arcade
game was chosen for the game. For the experi-
ment, each subject carried out a passive and an
active session. The active session involved play-
ing the computer game and evaluating the sound
quality of the game music. This session was de-
signed to cause a division of attention between
evaluating the audio quality and reaching a high
score. In the passive session, subjects were asked
to evaluate the audio quality while a game demo
was presented. Here, the attention of the subjects
was assumed to be directed to the audio quality
exclusively.
In both sessions, active or passive, either
the original (20kHz) game music, or a low-pass
filtered version with cut-off frequencies at f c =
11kHz, 12kHz or 13kHz was played. This was
complemented by an anchor with f c = 4kHz.
Thus a total of 5, 3-test items, 1 anchor item, and
1 reference item (corresponding to the original
full-range signal) were presented to the players
in the experiment. After each round of the game,

players were asked to rate the perceived tonal
quality degradation using the standardized ITU-
T P.911 (Recommendation ITU-T P.911, 1999),
5-level impairment scale.
A total of 32 subjects participated in the
experiment. Seven players were female and 25
were male (age M = 25.7, SD = 5.36). Regard-
ing their listening experience, 20 subjects were
considered initiated assessors and 12 classified as
naive assessors. The group of initiated assessors
had already gained abilities and knowledge in
rating audio quality in preceding unimodal and
bimodal subjective assessments. All participants
reported normal hearing and normal or corrected
to normal visual acuity.
A Wilcoxon T test showed that the quality
ratings of the active session varied significantly
from the ratings of the passive session for cut-off
frequencies up to 12kHz. A significant decrease
in rating correctness was shown for the active
session in comparison to the passive session for
the anchor item (T = 37, p ≤ 0.01), the cut-off
frequency f c = 11kHz (T = 452.50, p ≤ 0.01), and
the cut-off frequency f c = 12kHz (T = 812, p ≤
0.01). For the cut-off frequency of 13kHz and the