Music Perception: Paper ICA2016-727

Effects of lighting on impressions of popular music
Akira Nishimura(a) , Takuya Matsukawa(a)(a) Tokyo University of Information Sciences, Japan, akira@rsch.tuis.ac.jp

Abstract
This study focused on the effects of lighting colors on impressions of popular music in an actual
room, in contrast to a previous study, in which impressions of classical piano music were evaluated for colored images of a piano player generated through computer graphics. The previous
study did not clarify the effect of the lighting color on the difference in impression compared withthat under normal white lighting. This study investigated the impressions of six pieces of popular
music in a room under LED lighting in colors of white, red, yellow, green, and blue. The resultsof listening experiments conducted with 10 listeners were as follows: Red lighting induces strong
and dirty impressions, and blue lighting induces dark and gloomy impressions. These results
are consistent with those of the previous study. In addition, the finding of the previous study thatappropriate matching between the music and the lighting color enhances the impression createdby the music itself was generally observed. However, the degree to which this tendency holds
true was found to somewhat depend on the lighting color.
Keywords: SD method, Factor analysis, Correlation, Relative impression

Effects of lighting on impressions of popular music
1 Introduction
Impressions of music are known to be affected by the lighting in the listening environment.
Lighting plays very important role in live performances of music. The lighting technicians canaffect both hidden and obvious features of the music because the audience’s impressions of
the music will somewhat depend on the lighting.
The effect of the congruence between lighting and music was previously examined in experiments involving classical piano music played by a MIDI synthesizer and computer graphics ofa piano performance under various colors of lighting [3, 2]. The lighting colors used were red,
yellow, yellowish green, green, cyan, blue, violet and purple, which are equally spaced on the
Munsell hue circle. The musical stimuli were eight short musical passages from popular classical piano tunes. The affective impressions of the music as a function of the lighting color usedin the computer graphics and the degree of matching between the color of the lighting and themusic were measured through rating experiments. The results showed that the impressionsof the music pieces presented with red or purple colors were evaluated as powerful, whereas
those presented with a cyan color were evaluated as powerless. Moreover, colors of green,
yellowish green, yellow, and cyan enhanced bright impressions of the music, whereas colors ofblue, violet, purple and red enhanced dark impressions of the music. In general, a color thatmatched the music enhanced the affective impression created by the music itself. Powerfulmusic was matched with colors that made the music seem more powerful, and bright music
was matched with colors that made the music seem brighter.
However, the previous study described above was conducted based only on a computer display. The performer and the piano were generated through computer graphics. Moreover, theimpressions of the music in a normal white lighting environment were not measured. The impressions of the music under various colors were measured, but the baseline impressions of
the music were unclear. Therefore, the affective impression created by the music itself, which
was concluded to be enhanced by a color that matched the music, was not clear.
This study focused on the effects of lighting colors on impressions of popular music in an actual
room, intended to be representative of typical situations of listening to music or to backgroundmusic. LED (light-emitting diode) lighting, controlled by a computer, was illuminated in frontof a listener sitting in the room. White lighting, which is the normal lighting color of a room,
was examined in addition to blue, green, red, and yellow lighting. The impression that wasreported for a given music under white lighting was treated as the reference. The variations in
impression that were reported under other lighting colors were compared against the reference
and were analyzed to elucidate the effect of lighting on music.

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Table 1: Intensities of illumination under the five lighting colors.
Color (Abbrev.)
Blue (B)Green (G)Red (R)
Yellow (Y)White (W)Intensity [lux]
54
30
15
51
77

2 Experiment
2.1 Apparatus
A laboratory room, with approximate dimensions of 3.4 m × 5.4 m × 3.0 m in height, was used
for the experiment. The room was sealed to avoid the intrusion of light from outside the room.
Each listener sat on a chair located in the middle of the room. In front of the listener, a whitetable of 0.7 m in depth and 1.6 m in width was placed. Two LED lighting instruments (Fuloon
Lighting, LED Flat Mini Par Light) were placed on both sides of the listener at a distance of 1.5
m. Two stereo loudspeakers (YAMAHA NS-1000MM), 2.8 m apart, were placed to the left andright front sides of the listener.
The light was produced by 1-watt LED bulbs in colors of red, green, and blue; there were six
bulbs of each color. The lighting colors (blue, green, red, yellow, and white) were produced bylighting single bulbs (red, green, or blue), pairs of bulbs (yellow, generated by combining green
and red), and all bulbs (white). A Tondaj LX-1010B digital luxmeter was used to measure thevertical intensity of the illumination at a point 2.3 m in front of the listener at a height of 1.2 m.
Table 1 shows the intensities of illumination for the five lighting colors. Color temperature andchromaticity were not measured because no instrument was available to do so.
2.2 Musical pieces
Six pieces of music were selected from the RWC Popular Music Database [1]. A 30-second
sample of each piece was extracted from the beginning of the tune. A-weighted equivalentsound pressure levels were measured at the listener’s head position. The volume dial of theamplifier was fixed for all musical pieces. These pieces were also used in an initial informal
experiment conducted to investigate the impressions of the music to allow a comparison of two
independently collected sets of impressions of the music under white lighting conditions.
2.3 Method
The listeners were 10 young adults of 20–22 years in age. All 30 possible combinations of thesix musical pieces and the five lighting conditions were presented in a random order. The participants evaluated their musical impressions on 11 bipolar, 7-point semantic differential (SD)scales and assessed the degree of congruence between the music and the lighting. The adjective pairs used to assess the impressions were ‘dirty — clean’, ‘obscure — clear’, ‘unemotional

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Table 2: Musical pieces used in the experiments.
No.
1
2
3
4
5
6

RWC-MDB-P-2001
No. 96
No. 79No. 40No. 25
No. 24
No. 21

Tempo
130
92
122
103
130
98

A-weighted equivalent SPL [dB]
69
66
65
69
73
66

Table 3: Pearson product-moment correlation coefficients between two experiments conducted under white lighting.
Piece No.
Coefficient

1
0.909

2
0.964

3
0.828

4
0.555

5
0.952

6
0.739

— emotional’, ‘dislike — like’, ‘gloomy — cheerful’, ‘dark — bright’, ‘weak — strong’, ‘common— unique’, ‘ungraceful — graceful’, ’calm — excited’, and ’soft — hard’. Each bipolar item wasscored on an SD scale of –3 to +3.

3 Analysis
3.1 Comparison of impressions under white lighting
In the initial informal experiment, 83 young adult listeners evaluated their impressions of thesame six musical pieces using nine bipolar, 13-point SD scales under fluorescent lights of
350–500 lux. The nine adjective pairs that were used for these SD scales were a subset of theadjective pairs that were used in the current experiment. The Pearson correlation coefficientfor the average evaluation of the listeners of the nine scores between the initial and current
experiments was calculated for each musical piece.
The results are shown in Table 3. The correlation coefficients between the two experiments
under white lighting indicate a high degree of significance, except for musical piece No. 4. This
exception is due to the difference in the scores for cheerfulness; the initial result was slightly
gloomy, and the current result was neutral. The initial gloomy impression of musical piece No.
4 may have been caused by the contrast between the well-lighted room and the gloomy lyricsof the piece. In general, however, the impressions of the musical pieces under white lighting
did not considerably differ between the initial well-illuminated condition (350–500 lux) and theless illuminated condition (77 lux). Moreover, the average impressions reported by the current
participants did not considerably differ from those reported by a number of other young adults.

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Table 4: Factor loading determined in the factor analysis.
Adjective
+
Dirty
—
Clean
Obscure—Clear
Unemotional — Emotional
Dislike—Like
Gloomy— Cheerful
Dark—
BrightWeak—
StrongCommon—UniqueVariance [%]Communality
0.943
0.941
0.368
0.356
0.972
0.852
0.588
0.478

Factor 1
Clearness
0.820
0.970
0.600
0.595
–0.021
0.093–0.491–0.43946.0

Factor 2
Cheerfulness–0.520–0.0055–0.1110.0476
0.986
0.918
0.589
0.534
22.8

3.2 Effects of lighting colors on music
The variation of music impressions depending on lighting colors is observed from the differences between the impression scores reported under white lighting and those reported underother lighting colors. Henceforth, these differences in score are called ‘color effect scores’. A
three-way analysis of variance (ANOVA) in which the factors considered were the four colors(blue, green, red, yellow), the six musical pieces, and the 10 listeners was conducted using thecolor effect score for each impression. No significant difference was found in the interactions
between music and color. Significant differences were found in the listeners for all impressions.
The significant effects of the colors were as follows: red lighting causes the impressions of apiece of music to become stronger and dirtier, whereas blue lighting causes these impressions
to become darker and gloomier. These results are approximately consistent with those of theprevious study [3].
3.3 Factor analysis
The correlation coefficients between the scores of the graceful, calm, soft, and clear impressions averaged among the listeners that were obtained for the 30 combinations of stimuli werehighly significant, that is, greater than 0.8 for all combinations of impressions. Therefore, of
these four impressions, only the results for clear impressions were employed for the factor
analysis; the graceful, calm, and soft impressions were not considered.
Thus, a factor analysis using eight SD scales was conducted via the principal factor method,and varimax rotation was applied to the obtained factor loadings. Because an eigenvalue ofthe first two factors exceeded unity, a two-dimensional solution was adopted. Table 4 shows
the factor loadings determined in the factor analysis. Factor 1 and factor 2 are named ‘Clearness’ and ‘Cheerfulness’ respectively, based on the corresponding adjectives that showed the
maximum factor loading.
Figure 1 shows the two-dimensional factor scores for the 30 experimental conditions. The
abbreviations B, G, R, Y, and W represent the lighting colors, and the numbers 1—6 represent

5Bright

the numbers of the music pieces. The same musical pieces under different lighting colors tend
to form groups in the factor space, indicating that the variation of the impression depending on
the lighting color is not strong.
2
1.5

R5

Y5 G5

Y3
W5
G3 W3

R3

1

B5

0.5
Factor 2

R6
0

B3

-0.5

Y1
G4

-1

R4
R1

Y4
W4 W1
G1
B4

B1

-1.5
Gloomy

Y6

G6
W6
B6
Y2

R2

G2

B2

W2

-2

-2.5
-2.5 -2
Obscure-1.5-1-0.5 0
Factor 1

0.5

1

1.5 2
Clear

Figure 1: Two-dimensional factor scores for the experimental conditions. The letters B, G,
R, Y, and W represent the lighting colors. The numbers 1—6 represent the numbers of themusic pieces.

3.4 Enhancement of musical impression by lighting
Previous studies [3, 2] have argued that the appropriate matching of music with colors enhances the affective impression created by the music itself. However, in these studies, theaffective impression created by the music itself was not clear because the musical impressions
under normal white lighting were not measured.
This section focuses on the relationship between the relative changes in the impressions ofmusic in the factor space (Fig. 1) and the evaluations of the congruence between lighting andmusic.
Let Ci = (Ci1 ,Ci2 ) represent a vector of the stimuli in the two-dimensional factor space, where irepresents the ith piece of music (i = 1, 2, ..., 6) and C represents the color abbreviation (B, G,
R, Y, W). The strength of impression λCi of the stimulus Ci is expressed as the length of the6vector Ci :√2 +C 2 ,λCi = Ci1i2

(1)where Ci1 is the first factor score and Ci2 is the second factor score. Then, the strength ofimpression of the ith piece of music under white lighting is denoted by λWi . Therefore, the′ relative to the impression under the white lighting is calculated bystrength of impression λCi
obtaining the length of the vector Ci projected onto the direction of the vector Wi :′λCi
= λCi cos (αCi − αWi ),(2)

where αCi is the angle of the vector Ci . A graphical representation of this conversion process
in the factor space is shown in Figure 2.

Factor-2
R3
λG3
λR3
B3

λ’R3

Y3
G3

W3

λ’G3
αR3

αG3 αW3
Factor-1

Figure 2: Graphical representation of the projection of the impression vector for each lighting color Ci onto the axis of the white lighting vector Wi .
′ − λ , where C =B, G, R, Y and i = 1, 2, ..., 6, is derived as the enhancement effectFinally, λCi
Wion the impression that is induced by the lighting color compared with white lighting conditions. Positive values indicate enhanced impressions, and negative values indicate diminishedimpressions.

A scatter plot of the relative enhancement effect and the relative congruity between lighting
and music is shown in Figure 3. The correlation coefficient between the relative impression
enhancement and the congruity is 0.607 (N = 24), which is highly significant. The correlation
coefficients were calculated separately for each lighting color, resulting in values of 0.930 for
blue, 0.483 for red, 0.406 for yellow, and –0.668 for green. Thus, the general tendency thatappropriate matching between the music and the lighting color enhances the impression created by the music itself is confirmed. However, this tendency is strong for blue lighting, small
for red and yellow, and opposite for green. Note that the opposite tendency observed for green
lighting is vague because the values for both indices, the relative impression enhancement andthe congruity, are small.

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Difference of congruence compared to white lighting
Incongruous
Congruous

1.5
1
0.5

r(all) = 0.607
r(B) = 0.930
r(R) = 0.483
r(Y) = 0.406
r(G) = -0.668

B1
B6

0
Y2
G2

-0.5

R3

-1

Y1
B5

-1.5

R5

B2

R1

B4

G6
Y4
G1
R4
G3 G4
G5
Y5

Y6
Y3

R2
-2

B3

R6

-2.5
-2.5 -2 -1.5 -1 -0.5
0
0.5
1
1.5
Deminished
Enhanced
Difference of impression compared to white lighting

Figure 3: Relationship between relative enhancement of impression and congruence between lighting and music.

4 Discussion
The results of this study are broadly consistent with the results of the previous studies [3, 2]
despite the differences in the experimental conditions, that is, the music genre (popular contemporary music versus popular classical music) and the lighting environment (actual lighting
in a room versus simulated lighting in computer-generated graphics).
The previous study extracted three principal components, namely, powerfulness, brightness,and emotion, through a principal component analysis using 15 SD scales. This study did not
extract the factor of powerfulness because the SD scales included few adjective pairs that areusually classified together into the powerful factor. The ‘strong — weak’ impression, which isusually included in the powerful factor, was approximately equally loaded into the two extracted
factors of clearness and cheerfulness. When all 11 SD scales were used for the current factor
analysis, the three factors of brightness, emotion, and clearness were extracted. Again, the‘strong — weak’ impression was found to be loaded into all three factors approximately equally.
The listening experiments were conducted under less strongly illuminated conditions (below
77 lux) compared with the informal experiments, which were performed under well-illuminatedconditions (350–500 lux). The reported profiles of the impressions of the music did not considerably differ under these two conditions. However, the extent to which the impressions ofmusic remain the same under darker conditions, such as in the pitch dark, is not clear. The

8dependence of musical impressions on the intensity of illumination will be a future subject of
research.

5 SummaryThis study focused on the effects of lighting colors on impressions of popular music in an
actual room, in contrast to a previous study in which impressions of classical piano music were
evaluated based on the presentation of a colored image of a piano player generated throughcomputer graphics. LED lighting, controlled by a computer, was illuminated in front of a listenersitting in a room. White lighting, which is the normal color of room lighting, was presented inaddition to blue, green, red, and yellow lighting while the listener was listening to a music piece.
The impressions of the music pieces under white lighting were treated as the references. The
variations in impression that were reported under other lighting colors were compared against
the corresponding reference and were analyzed to elucidate the effect of lighting on music. Red
lighting was found to induce strong and dirty impressions, and blue lighting was found to induce
dark and gloomy impressions. These results are consistent with those of the previous study.
In addition, the finding of the previous study that appropriate matching between the music andthe lighting color enhances the impression created by the music itself was generally observed.
However, the degree to which this tendency holds true was found to somewhat depend on thelighting color.

References[1] M. Goto, H. Hashiguchi, T. Nishimura, and R. Oka. RWC music database: Popular, classical, and jazz music databases. In Proceedings of the 3rd International Conference on Music
Information Retrieval (ISMIR 2002), pages 287—288, 2002.
[2] S. ichiro Iwamiya. Cross-modal relations in mutimedia, chapter 7, pages 149—151. Oxford
University Press, 2013.
[3] S. ichiro Iwamiya and K. Hayashi. The effects of color on the impression of music. Design
issue of Kyushu Institute of design, 1:63—68, 1999.

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