2008:092 CIV MASTER'S THESIS Orchestration of Information
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2008:092 CIV MASTER'S THESIS Orchestration of Information and Warning Sounds in a Car Josefin Grönlund Luleå University of Technology MSc Programmes in Engineering Arena, Media, Music and Technology Department of Human Work Sciences Division of Sound & Vibrations 2008:092 CIV - ISSN: 1402-1617 - ISRN: LTU-EX--08/092--SE
2008:092 CIV MASTER'S THESIS Orchestration of Information
2008:092 CIV
M A S T E R ' S T H E S I S
Orchestration of Information and Warning Sounds in a Car
Josefin Grönlund
Luleå University of Technology
MSc Programmes in Engineering Arena, Media, Music and Technology
Department of Human Work Sciences
Division of Sound & Vibrations
Orchestration of information and warning sounds in a car
Josefin Grönlund
May 14, 2008
Abstract This report presents how new information and warning
sounds in a car were created and tested, to see what makes a chime
understandable, pre- mium and suitable for a Volvo. Premium is in
this thesis defined as high quality and luxury.
The amount of information to the driver is increasing and thus also
the necessity of methods to make it possible for the driver to
understand and respond to the message in a correct way without
disturbing the driving. The sounds should keep high quality and
acceptance.
Chimes of various categories were created in a music computer
program. Both a pilot study containing a listening test on tone and
a chime listen- ing test were carried out to analyze the
sounds.
The tests showed that if a chime is repeated continuously, it is
under- stood as a reminder – most often as seat belt reminder. But
the seat belt reminder should be a dedicated sound to avoid
confusions. A general in- formation chime is most easily recognized
and suitable if the sound is a simple melody of a few notes or
consists of beeps, like typical informa- tion jingles heard for
instance at a train station or from a computer. The warnings of
high urgency should be alarming, fast, clear and loud but not
frightening. A sound is judged as premium if it is soft, clean and
round. The tone of a flute is not premium in this context. Another
instrument, namely trumpet, which constitutes two warning sounds,
is not appreci- ated either. The participants expressed that a
Volvo sound should be like a premium sound and should also sound
secure and be understandable.
Acknowledgements Thanks to my supervisors, Martin Fagerström and
Thomas Lindgren, and other co-workers at Volvo Car Corporation. It
has been a privilege to work with you.
Thanks to my supervisors, professor Anders Ågren and Arne Nykänen
at LTU, who has guided me through this process.
Thanks to the Sonic Studio group at Interactive Institute in Piteå,
for let- ting me use your studio and for instructing me how to use
it.
Thanks to Malin Albing at the Department of Mathematics at LTU, for
help with the statistics.
Thanks to Caroline Vilsson for help with the english
language.
Thanks to my family and friends for support and crazy ideas.
David, Thank you.
And finally a huge thank you for everything to The One.
CONTENTS
Contents
2.2 Perceived urgency . . . . . . . . . . . . . . . . . . . . . .
5
2.4 Music . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. 7
2.6 Volvo sound strategy . . . . . . . . . . . . . . . . . . . . .
8
3 Method 9
3.2 Pilot study on tone . . . . . . . . . . . . . . . . . . . . . .
9
3.3 Creating the chimes . . . . . . . . . . . . . . . . . . . . .
10
3.3.1 The author’s initial scattered thoughts about the new chimes
. . . . . . . . . . . . . . . . . . . . . . 11
3.3.2 The author’s intention with the characters in the final chime
suggestions . . . . . . . . . . . . . . . 12
3.4 The existing chimes and background noise . . . . . . . 16
3.5 Testing the chimes . . . . . . . . . . . . . . . . . . . . . .
16
3.5.1 Selection of the participants . . . . . . . . . . . .
17
4 Results 18
— 1 —
CONTENTS
4.1 Question 1 - What do you think the sound intends to warn or
inform about? . . . . . . . . . . . . . . . . . . . . 18
4.2 Question 2 - Which degree of warning do you think the sound
belongs to? . . . . . . . . . . . . . . . . . . . . . . 18
4.3 Question 3 - Premium . . . . . . . . . . . . . . . . . . . .
20
4.4 Question 4 - Appropriateness to the sound category and in a
Volvo . . . . . . . . . . . . . . . . . . . . . . . . . 22
5 Discussion 24
C Plots of the acoustical quantities IV
D Listening test on chimes XIV
E Plots of the result from the listening test XXIII
— 2 —
1 INTRODUCTION
1 Introduction
The development of technologies makes it possible to detect
different kinds of occurrences and threats in the traffic
surrounding the car. In- formation about this and services like
telephone and email are making their way into the car. Together
with the already existing information about speed and fuel level,
there is a lot of information for the driver to adopt. Since the
visual modality already is heavily strained, many new chimes and
tinkles want to deliver information without competing with the
concentration on the traffic.
This report assesses suggestions of several sounds that could be
used as information bearer in an in-vehicle situation, in this work
referred to as chimes. The design of the chimes is supported by
conclusions from ar- ticles that discuss psychoacoustics, human
perception, auditory warn- ings and sound strategies. It is of
great importance that the chimes are accepted and understood, so
the sound is not switched off and no mea- sures taken on the error.
How is that done? What makes a sound de- liver a message and inform
the listener about an action that has to take place? What makes it
sound luxurious and high quality, in Volvo-words, Premium? What is
a volvoish sound? And what could it sound like?
By order of the supervisors at Volvo Car Corporation, only chimes
con- nected to the purpose from four warning groups were made and
tested. The warning groups were informational (I), reminder (R),
warning low (WL) and warning high (WH). No reaction, response or
response time to the chimes were tested, only the participants’
opinions.
— 3 —
2 THEORY
2 Theory
This section gives an insight in parts that can affect the
understanding of, attention to, taste of, opinion of, reaction to
and response to sounds.
There are two main groups of sound, noise aside: speech and
non-speech. Speech is easy to understand – a big amount of
information or complex information can easily be delivered. On the
other hand speech is depen- dent on language, something that
non-speech is not to the same extent. Non-speech can make you
understand and respond quickly. If there is a lot of other speech
heard or other noise, a non-speech sound can be eas- ier to hear.
One division of non-speech is auditory icons and earcons. These
match different situations depending on response time, annoy- ance
and urgency. (Fagerlönn 2007b)
2.1 Earcon and auditory icon
An earcon, is like a jingle. It can be anything between a single
simple beep to more of a complex melody. The meaning of the earcon
can not be figured out by its content but has to be learned.
Unlike earcons, auditory icons could be understood even the first
time they are heard. An internal division of the auditory icons is
nomic, sym- bolic and metaphoric mapping (Edworthy & Stanton
1995). Nomic map- ping is the actual sound of the event. An example
from the everyday life is the sound of opening a can with a can
opener. Metaphoric mapping can be the sound of something totally
different but evokes some kind of association to the event. The
opening of a squeaky door could be a metaphoric mapping of opening
a can. Symbolic mapping is a sound of something related to the
event or a created sound that is similar to the sound of the event.
A symbolic mapping of opening a can could be a tone sweeping from
low to high frequency.
Recognition of a direct relation sound requires little training.
Symboli- cal and metaphorical associations affect learnability
equally, at least for relatively easy tasks (Keller & Stevens
2004).
A good second choice after the direct association is a strong
indirect as-
— 4 —
2 THEORY
sociation to the auditory icon. It is not always possible to find a
direct association. Icons with a direct association is better than
an indirect re- lation, if there is no specific objection that
would make it inappropriate (Stephan et al. 2006).
In an experiment performed by Lemmens et al. (2001), it was found
that earcons slow down the response time and auditory icons have
the oppo- site effect. It is very important that the sound and the
visual event make a unanimous unit to avoid even slower responses
than with neutral con- ditions.
2.2 Perceived urgency
According to Edworthy et al. (1991) the parameters that unturbidly
effect the perceived urgency are: fundamental frequency, harmonic
series am- plitude envelope shape, delayed harmonics, speed,
rhythm, pitch range and melodic structure.
A later study by Haas & Casali (1995) has confirmed and
explored some of the parameters. It showed that regular rhythm of
pulses is more urgent than irregular pulse rhythms and inter-pulse
intervals should be kept as short as possible. The mean response
times for high pulse rate turned out shorter than for low pulse
rate. In their example with pilots the response time was actually
60 ms faster with a high pulse rate. Such a short time- range as 60
ms can be a dividing line between a crash and no crash in an
emergency in air traffic. Even in a traffic situation on the ground
parts of a second can make a huge difference.
Sequential pure tone signals lead to longer response times than
simulta- neous and frequency-modulated tones (Haas & Casali
1995). Hellier et al. (1993) had also earlier found that speed and
frequency was alerting pa- rameters, but that speed had a deeper
impact. A change in pulse rate and repetition rate will faster
obtain a difference in perceived urgency than a change of
fundamental frequency.
The sound of emergency vehicles directly gives a feeling of
urgency. And sequences with two alternating tones were in a study
caught as more ur- gent than others. The most effective alarms are
those that eventuate in an immediate association and from that a
direct response like a hard brake
— 5 —
(Guillaume et al. 2003).
A spontaneous response to the relation between annoyance and
urgency is that the more annoying a sound is the more urgent it is
perceived. But according to studies by Marshall et al. (2001)
parameters that make a warning sound more urgent is not necessarily
more annoying. To get a high urgency warning with fairly low
annoyance, the sound should have high density, a slow speed and
contain frequency series.
2.3 Driver’s workload
Driving is a complex situation with a lot of impressions to deal
with and make decisions from. Inside the car there are lamps and
icons that are lit to keep the driver posted about the state of the
car. More advanced vi- sual displays are making their way into the
car and the workload, that is already heavy saddled with the
traffic situation, gets yet another source of information to deal
with. With these displays follow sounds of different kind. Trials
with both visual dash-mounted display and conventional au- ditory
warning or auditory icon evoked faster response times than with
only the visual display. The same result was found with solely
auditory icons. But the combination of visual dash-mounted display
and auditory icon resulted in fewer collisions in the test. In the
situation of a front- to-rear collision the participants preferred
auditory and dash-mounted visual display. For side collision
warning the most preferred was mirrors, dash-mounted visual display
and auditory display all together (Belz et al. 1999).
The brain has a lot of data to process, and information in various
cos- tumes seems to be the best solution. The auditory and tactile
informa- tion facilitate the sight. It is suggested a multimodality
display to achieve this. This is also what the participants in a
study by Liu (2001) preferred to use. But in a combination of
complicated driving and a lot of instruc- tions produced, a memory
interference problem appears and even the auditory display is hard
to observe. What kind of presentation that suits the best is
dependent on the situation. It is also important to make the
information or instructions simple in order to decrease the
workload.
Wiese & Lee (2004) saw a tendency that annoyance may affect the
work- load strongly rather than the urgency mapping. Therefore
perceived an-
— 6 —
2 THEORY
noyance ought to be more considered than perceived urgency. This is
supported by Marshall et al. (2007). They found that
appropriateness is more related to perceived annoyance than to
perceived urgency. Some parameters affect perceived urgency more
than perceived annoyance. The context affects both perceived
urgency and perceived annoyance. The parameters that improve
perceived urgency without large changes in perceived annoyance
were: pulse duration, interpulse interval, alert offset, alert duty
cycle and sound type.
2.4 Music
Music has a way of influencing a persons mood. This is prominent
es- pecially in computer games and films. Music is there to create
an at- mosphere and convey warnings about danger, excitement,
harmony and so on. Short sequences of music in various
constellations with low and medium levels of urgency can be
understood even in a traffic situation as warnings. In an
experiment the warnings were not experienced as an- noying but may
be unappropriate the more urgent the situation is (Fager- lönn
2007a).
2.5 The way of listening
Depending on the situation, humans listen to sounds in different
ways. When listening to music, we can hear a specific component, a
specific in- strument. This is called musical listening. But when
we hear sounds that occur because of a subject’s shape and material
and an occuring event, we mostly listen to the event or the source
of the sound, not its acoustical components (if it is not
intentional). In other words we do not listen to which frequencies
are involved, the timbre, the rhythm, but that a fast snowmobile is
approaching on a snowy field. This is called everyday lis- tening
(Gaver 1993).
— 7 —
2.6 Volvo sound strategy
The Volvo sound strategy suggests six categories of information
sounds: Warning high, warning low, reminder, informational,
feedback and info- tainment informational. They represent different
situations in the driv- ing process. Warning high is extremely
urgent, the response time has to be less than one second, the
situation has severe imminent danger. Warning low signals possible
danger and has a response time limit to ten seconds. The
informational chime invites the driver to take some action. The
reminder also invites the driver to take some action but because of
some by the driver forgotten action. Feedback informs of action
initi- ated by driver or passenger. The infotainment informational
gives signals about the infotainment system (Davidsson &
Fagerström 2007).
— 8 —
3.1 Analysis and presentation of problem
The existing chimes in Volvo cars are few and relate to several
different actions. This is confusing to the driver. Since the
chimes usually do not sound especially often, it can be hard to
know what they mean. Learning- time does not exist, except for the
seat belt reminder, which might occur every time the driver is
seated.
A common chime, like the seat belt reminder, should be easily
accepted and discreet. There are in the present no particulary
volvoish sound ex- cept the seat belt reminder, which perhaps is
too simple to be premium.
3.2 Pilot study on tone
To get a clue about the relation between tone and premium, a simple
lis- tening test was made (Appendix B). Four different tones,
collected from the music computer program Steinberg Nuendo Version
3.2.1, were tested. Vibraphone, Synthesizer sound like a damped
vibraphone, trumpet and a flute. These four sounds are more or less
well-known instruments with different characters and tones. A note
525 Hz (C5) was played two times for each tone. The participants
were asked to grade them and by pairwise comparison decide which
tone was most premium.
The eleven participants, six women and five men in the ages between
17 and 61, where all in the author’s circle of acquaintances. The
majority of them were amateur musicians and some of them had used
computer music programs like Cubase.
It showed that the airy tone of a flute was experienced as not
especially premium, neither the trumpet. The synthesizer sound with
its soft and sonorous tone was elected as the most premium tone.
There were also comments about the difference in the quality of the
tones as the signal to noise ratio and that some sounded as flat
and simple midi files.
— 9 —
3.3 Creating the chimes
The chimes were created in the same program as the tones, Steinberg
Nuendo Version 3.2.1. With respect to the tone listening test, a
literature study, the Volvo sound strategy and the existing chimes,
the new chimes were developed. The suggestions belonged to four
categories represent- ing four urgency grades. The following
situations should have chime suggestions. Forward collision warning
(FCW), parking brake (PB) ac- tive while driving, seat belt
reminder (SB) and information (Info) of any kind. The situations
belong to the four categories respectively, warning high (WH),
warning low (WL), reminder (R) and informational (I) (table
1).
Table 1: Excerpt from the Volvo sound strategy 1.4 Name Type Sound
character Pitch Repetition Duration FCW WH Dedicated chime. The
sound
character shall convey a high ur- gency/criticallity message. Ac-
ceptance not that critical. Ex- ample: CAMP sound
high short in- terval
3 cycles
PB WL General chime. The sound char- acter shall convey a high ur-
gency/criticallity message. Ac- ceptance of the sound has to be
considered.
medium cont. in- creasing
SB R Dedicated chime. Premium, ac- ceptance of the sound is of high
importance. Classic belt re- minder.
medium cont. in- creasing
Info I Premium, acceptance of the sound is of high importance
medium short in- terval
3 METHOD
3.3.1 The author’s initial scattered thoughts about the new
chimes
This section contains the author’s first ideas from which the
chimes later were developed. Some of the ideas were similar to the
Volvo strategy. The items in this section were not handled as
demands but as guidelines.
• All the chimes should be suitable in a Volvo, informative or in
other words give a hint of the meaning, intention or the desired
action. Every chime should also be judged as Premium. This is less
impor- tant for the more urgent chimes, especially the FCW.
Forward Collision Warning (FCW) - Warning High
• To signal the urgency and elicit a fast correct response, as a
hard deceleration.
• Signal horn - short pulse and interval (Hellier et al. 1993, Haas
& Casali 1995, Guillaume et al. 2003, Keller & Stevens
2004, Stephan et al. 2006, Marshall et al. 2007).
• Loud! 15-30 dB over the noise (Haas & Casali 1995, Baldwin
& Struckman- Johnson 2002).
• Strong, lots of bass, or sharp and more of the high
frequencies.
• Placement - from the threatening direction.
• Low acceptance. It is there to alert danger.
Parking brake - Warning Low
• Creating a feeling of that something is wrong and an action
should take place in a fairly short time period.
• Metal scrape, sound of a parking brake being pulled, voice.
• Placement - by the parking brake, driver’s seat.
— 11 —
Safety belt - Reminder
• Should request the driver or passenger in a nice and not annoying
way, to fasten the seat belt.
• Intensifying and more sharp as time goes by.
• A bit dissonant. Consonant when seat belt fastened.
• Two or three notes.
• Mean acceptance since the sound comes often.
Information - Informational
• Make the driver aware of that information is available on the
dis- play.
• Typical information bell, voice.
• Placement - in front of the driver.
• Good acceptance. The sound should inform in a nice and friendly
way.
3.3.2 The author’s intention with the characters in the final chime
suggestions
In consultation with co-workers and supervisors at Volvo, three
sounds in each category were chosen, except for the information
chime where four sounds were chosen, since there was no existing
chime of that kind. For a more detailed description of the sounds
see table 2 and 3.
— 12 —
3 METHOD
The info chimes were meant to sound similar to typical information
sound for instance from the computer or at the train station. They
were, above all, short.
The seat belt chimes were all continuous and slow. The sound of SB1
was put together to be friendly and bright. SB2 and SB3 were a bit
dissonant to signal, like ambience music in a film, that something
is wrong and has to change.
There were trials of making an auditory icon for the parking brake
chime. Sounds of different metal scrape and the mechanical sound of
the park- ing brake handle being pulled were recorded and adjusted,
but they were in the author’s ears, hard to understand and connect
to their purpose. Instead, a clearly dissonant tone was used in PB1
and PB2. PB3 had an- other variant of musical approach. It was made
of three slightly disso- nant falling notes, and was meant to sound
nice but give a hint that all is not well. The PB chimes were as
the Info chimes, short. They were intended to be repeated if no
action had taken place.
As mentioned in section 2.2 auditory icons increase the response
time and would therefore be appropriate in an emergency. The only
chimes that were auditory icons were the FCW chimes. The FCW1’s
sound was a modified recording of a horn in a Volvo S80. It staged
the scenario of a threat in front of the car. A car horn is to some
extent a trumpet sound. And this was taken into account when FCW2
and FCW3 were created. They were both based on a trumpet tone. The
only difference was the speed of the pulses and notes. All the
three FCWs were rapid and contin- uous pulses.
— 13 —
3.4 The existing chimes and background noise
The existing chimes were recorded in a Volvo S80 with Head
Acoustics NoiseBook.
To get a more realistic feeling in the test, car background noise
was added to the chimes. The background noise was recorded with
Head Acoustics NoiseBook in a Volvo XC70 with winter tyres without
studs, driving on a even, dry asphalt road. One sequence was
recorded when the speed was 90km/h and the other one was start of
engine and departure. For acous- tic quantities such as loudness
see Appendix C. The continuous back- ground noise was added to the
Info and FCW chimes. The start noise was added to the PB and SB
chimes. The proportion between the levels of signal and noise was
adjusted by listening and comparing with a real driving
situation.
3.5 Testing the chimes
The listening test was performed in a sound car of model Volvo S80
- 01 to give a more realistic feeling. The sound car had a computer
with Head Analyser Artemis version 6.00.200 installed and two
headphones, Sennheiser HD600. The participants were placed in the
driver’s seat and the test leader in the front passenger
seat.
The test leader was present during the whole procedure to note
spoken thoughts, explain obscurities and to manoeuvre the
chimes.
The chimes were presented in four different orders, to avoid
different kinds of side effects. Hence each order were heard by
three or four par- ticipants.
The test participants wrote down their opinions in a questionnaire
con- taining both grading and open questions (see Appendix D). The
open questions dealt with the comprehension of the chimes and
suggestions of what qualities a chime should have corresponding to
its information and character. The grade scale was from one to ten,
with explanatory words to each step. This is the scale that is most
often used in tests at Human Machine Interaction department at
Volvo Car Corporation. The participants graded the chimes according
to premium, suitability in a
— 16 —
3 METHOD
Volvo, suitability to the sound category, frightening and attention
grab- bing. The two latter were only considered for the FCW chimes.
One task was also to match the chimes with four warning
degrees.
3.5.1 Selection of the participants
The participants were chosen from a test pool within Volvo. The
only de- mand on the participant was that he or she was in
possession of a driver’s licence. The desire was to have a uniform
age structure and gender dis- tribution. Since only 14 persons gave
their positive response to the invi- tation all of them were
selected, six women and eight men. The age span was between 28 and
57 with a mean of 44 years.
— 17 —
4 RESULTS
4 Results
Since the questions of open character results in answers where the
words are not exactly alike, the answers have been categorized into
larger groups by the author. The author listened to the chimes
several times and at the same time read the answers to understand
how to interpret them. The words that were most often used are
those presented in this report. That also goes for words that
described the sound in different ways but in the same spirit.
4.1 Question 1 - What do you think the sound intends to warn or
inform about?
The parking brake sounds and information sounds were mostly under-
stood as some kind of information and sometimes as a mild warning.
Further some thought that PB2 and PB4 sounded like a park assist.
One especially remarkable thing was that PB4 was understood of
twelve par- ticipants to be seat belt reminder.
The seat belt reminder chimes were mostly interpreted as seat belt
re- minder, especially SB4. Only two participants did not make a
note of that, but neither of them were Volvo drivers. Other
possible events were information, door open, and SB3 announced to
three participants ex- pressly that the driver had forgotten to
take some action.
Even if the FCW sounds were understood as different kinds of
collision warnings and lane departure warnings, they were easily
interpreted as warnings of a dangerous situation.
4.2 Question 2 - Which degree of warning do you think the sound
belongs to?
The most outstanding category in this question was Warning High.
The FCW4, which was thought of as the most suitable in a Volvo and
the least
— 18 —
4 RESULTS
scary, was the hardest of the FCWs to categorize. But still only
two partic- ipants guessed on something other than WH. FCW1 and
FCW2 had 100% correct guesses. No one marked a sound as WH when it
was not (figure 1). All the chimes were short, fast, loud and
continuous.
Figure 1: Diagram showing the result of the categorization of the
chimes.
According to the Volvo sound strategy 1.4 the Parking Brake is a
Warning Low, but in the latest version it is a reminder. The
existing chime was indeed without exception classed as a reminder,
probably because of its continuity. Only PB1, which also had the
highest mean value in the ques- tion about appropriateness to the
sound category, was judged by scarcely half of the group as a WL.
It was the most clearly dissonant and slowest, but still short, of
the created PB chimes. PB1 was similar to PB2 in its dissonance and
sound type. The difference between them were mainly that frequency
and speed was higher in PB2, which seems to effect the
comprehension of that chime as information or reminder. PB3 and
Info4 seemed to be caught as quite alike. They both were little
melodies of three notes, which in the ears of the participants were
connected to in- formation.
At least half of the participants placed the information chimes in
the information category. The participants were actually unanimous
about Info4’s category. The unanimity might be because of the
similarity with information chimes in computers or public places
like a train station. The categorization of Info1 and Info3 looked
almost the same. It seems like two short notes of the same
frequency have the effect of sounding
— 19 —
4 RESULTS
more urgent than for instance the sound of Info2, so Info1 and
Info3 were therefore marked as WLs.
The seat belt reminder chimes were over all marked as reminders.
The existing seat belt reminder was recognized as a reminder of
everyone ex- cept one. SB1 had higher frequencies and a more
bell-like sound, which might have influenced to put it as an
information. SB2 was more dull, compared to SB1, contained lower
frequencies and a higher percentage judged it as a reminder.
4.3 Question 3 - Premium
The questionnaire and also the answers of the participants were
written in Swedish. The words used to describe sound in the answers
to question 3-4 have been compiled and translated by the author and
can be found in table 4.
In the opinion of the participants a premium sound was comfortable,
soft, clean and round. Some wanted it to be musical with more than
one note, some did not. Some wanted it to be something like a sound
from a computer, some did not. The opinions were there clearly
splayed. But the opinions were rather unanimous about what was not
a premium sound namely harsh, hollow, angular, sharp, annoying,
flat, boring, large dynamics and beepy (figure 2).
Figure 2: Scheme of the words describing "Premium".
— 20 —
Table 4: Compilation of the participants’ words to describe sound.
Swedish English (translation) Aggresivt Aggressive Alarmerande
Alarming Kantigt Angular Irriterande Annoying Uppmärksammande
Attract attention Pipigt Beepy Tråkigt Boring Rent Clean Tydligt
Clear Behagligt Comfortable Kontinuerlig Continuous Distinkt
Distinct Platt Flat Skrämmande Frightening Luddiga toner Fuzzy
notes Hårt Harsh Ihåligt Hollow Snällt Kind Stor dynamik Large
dynamics Starkt Loud Melodiskt Melodic Tyst Quiet Igenkännlig
Recognizable Runt Round Säkert Secure Skarpt Sharp Skränigt Shrill
Enkelt Simple Mjukt Soft
The ranking of the sounds in the preference of Premium shows that
SB1 was significantly higher graded than PB2 (figure 3).
Interestingly they share the same synth tone. SB1 and PB2 had
similar sharpness values but differ considerably in tonality and
roughness. SB1 had 1.1 ton/tu. and 4 R/asper compared with PB2’s
0.7 ton/tu. and 14 R/asper (table 3), which seems to be experienced
as more aggressive and therefore less premium.
The following is not statistically significant but might point to
something interesting. PB2 and Info1 had the lowest mean-values,
but the reason seems to differ. PB2 was disliked probably because
of its roughness. Info1 had low roughness value but the sound of a
flute. Like the listening test on tones, it was not appreciated as
a premium sound. Roughness ap-
— 21 —
4 RESULTS
Figure 3: Plot of the grade of "premium" for Parking brake,
Information and Seat belt chimes.
peared to be important also in the four chimes with highest means.
They shared the low roughness values, even if they were different
in tone and note character. They had also the highest values of
tonality.
4.4 Question 4 - Appropriateness to the sound category and in a
Volvo
The information, the parking brake and the seat belt chimes had
this in common, they should all be soft and attract attention,
according to the participants (figure 4). The information chime
should be simple, melodic and recognizable from other electronic
devices like computers and tele- phones. The parking brake chime
should be continuous, which also goes for the seat belt reminder.
But the latter should have a dedicated sound. These three
categories of chimes should not be frightening, aggressive, loud,
quiet, harsh or shrill. The parking brake chime should furthermore
not sound like the seat belt reminder.
The participants expressed that the most deviant chime, the FCW,
should be loud, clear, fast, alarming and not frightening. On the
other hand it should not be kind, fuzzy notes, to loud or to
quiet.
FCW4 is significantly higher graded than FCW2 and FCW3 in the ques-
tion of suitability in a Volvo (figure 5). Some spoken comments on
what FCW2 and FCW3 sounded like were: "circus on the road", "brass
band"
— 22 —
4 RESULTS
Figure 4: Scheme of the words describing the sound for each
category.
and "reveille".
Figure 5: Plot of the grade of suitability in a Volvo for Forward
Collision Warnings.
Similar words to those that described how a Premium sound should
be, was also used to describe how a Volvo should sound. It should
also be melodic, clear, secure, distinct and everyone should
understand it. It should not be a melody nor a monotone or annoying
sound (figure 6).
— 23 —
4 RESULTS
Figure 6: Scheme of the words describing the sound in a
Volvo.
— 24 —
5 DISCUSSION
5 Discussion
The questionnaire contained qualitative questions, which were put
to- gether. But there were also questions of quantitative
character. Pairwise comparisons were considered but since grades on
the chimes were desir- able the Volvo-scale, which is known and
often used at Volvo, was used in this work.
The choice of words in question number two is maybe a bit
misleading. "Grade of warning" could give a false idea that the
different words or cat- egories is like a stepwise warning like a
grade 1 to 4. But they are divided in these groups because of how
fast the driver has to give response. A better expression could
have been "warning category".
The categories in the same question as above, were not explained to
the test participants. So it was in the eye (ear) of the beholder
to judge whether a chime that sounds like a seat belt reminder
really is a reminder or a Warning Low. This of course effects the
result.
All the participants were employees at Volvo Car Corporation, which
could be inappropriate. The results indicate that even in such a
group the opin- ions are various.
The sounds were randomized in the first three questions to avoid
any kind of side effects. Because of a mistake, remaining chimes
were not randomized. Every participant listened to the chimes in
the same order. The risks of fatigue factors and training effects
are very small as there were 16 different chimes and only four
chimes at a time to listen to in every category and they had
already been heard in the previous tasks but in a different order.
Order effects on the other hand might be present.
5.1 The future
To get a better idea about the chimes, they ought to be implemented
and tested in a live situation. The opinions may be different than
in this trial. It would also be interesting to measure reaction and
response time.
When a premium sound is found the following questions could lead
the
— 25 —
5 DISCUSSION
progress ahead. What kind of equipment is required to achieve a
pre- mium sound? Can the ones used today handle frequencies as low
as 380 Hz? Is it desirable to make it possible for the user to
personalize the chimes?
Humans have the possibility of hearing direction of the sound
source. To make information in the car as clear as possible this
quality should also be utilized. A seat belt reminder should not be
heard just by the driver but by the passenger that has no seat belt
fastened. The sound concerning the parking brake should sound as if
it comes from the parking brake. This is already dealt with in
films and computer games. That stereo or surround effect has been
used for several decades in music mixing. Since the technical
development is heading forward and more complex sounds like music
are possible to implement in the car, it should be considered and
explored. But it must be taken into account that different people
do not have the same ability to catch musical changes.
Speech is also an interesting field to study more. Speech alone and
speech combined with chimes. We are used to the human voice and
react fast to it.
There are many ways to change a sound and a small change can make a
big difference.
— 26 —
REFERENCES
References Baldwin, C. L. & Struckman-Johnson, D. (2002),
‘Impact of speech pre-
sentation level on cognitive task performance: implications for
audi- tory display design’, Ergonomics 45:1, 61–74.
Belz, S. M., Robinson, G. S. & Casali, J. G. (1999), ‘A new
class of auditory warning signals for complex systems: Auditory
icons’, Human Factors 41:4, 608–618.
Davidsson, S. & Fagerström, M. (2007), Volvo sound strategy
1.4.
Edworthy, J., Loxely, S. & Dennis, I. (1991), ‘Improving
auditory warn- ing design: relationship between warning sound
parameters and per- ceived urgency.’, Human factors 33(2),
205–232.
Edworthy, J. & Stanton, N. (1995), ‘A user-centred approach to
the de- sign and evaluation of auditory warning signals: 1.
methodology’, Er- gonomics 38:11, 2262–2280.
Fagerlönn, J. (2007a), Expressive musical warning signals., in
‘ICAD 2007 - The 13th International Conference on Auditory
Display’, Interna- tional Community for Auditory Display.
Fagerlönn, J. (2007b), Informative auditory warning signals: a
review of published material within the HCI and auditory display
communities., in ‘Proceedings of the 39th Nordic Ergonomics Society
Conference, 1-3 October 2007, Lysekil, Sweden’, Nordic Ergonomics
Socitety.
Gaver, W. W. (1993), ‘What in the world do we hear? an ecological
ap- proach to auditory source perception.’, Ecological perception
5(1), 1– 29.
Guillaume, A., Pellieux, L. & Drake, C. (2003), ‘Judging the
urgency of nonvocal auditory warning signals: Perceptual and
cognitive pro- cesses’, Journal of experimental psychology: Applied
9:3, 196–212.
Haas, E. C. & Casali, J. G. (1995), ‘Perceived urgency of
response time to multi-tone and frequency-modulated warning signals
in broadband noise’, Ergonomics 38:11, 2313–2326.
Hellier, E. J., Edworthy, J. & Dennis, I. (1993), ‘Improving
auditory warn- ing design: Quantifying and predicting the effects
of different warn- ingn parameters on perceived urgency’, Human
factors 35(4), 693–706.
— 27 —
REFERENCES
Keller, P. & Stevens, C. (2004), ‘Meaning from environmental
sounds: Types of signal-referent relations and their effect on
recognizing au- ditory icons’, Journal of experimental psychology:
Applied 10:1, 3–12.
Lemmens, P. M. C., Bussemakers, M. P. & de Haan, A. (2001),
Effects of au- ditory icons and earcons on visual categorization:
the bigger picture, in ‘Proceedings of the 2001 International
conference on auditory dis- play, Espoo, Finland, July 29-August 1,
2001’, International Community for Auditory Display.
Liu, Y.-C. (2001), ‘Comparative study of the effects of auditory,
visual and multimodality displays on drivers’ performance in
advanced traveller information systems’, Ergonomics 44:4,
425–442.
Marshall, D. C., Lee, J. D. & Austria, P. A. (2007), ‘Alerts
for in-vehicle in- formation systems: Annoyance, urgency and
appropriateness’, Human factors 49:1, 145–157.
Marshall, D., Lee, J. D. & Austria, P. A. (2001), Annoyance and
urgency of auditory alerts for in-vehicle information systems, in
‘Proceedings of the Human factors and ergonomics society 45th
annual meeting - 2001’, Human factors and ergonomics society, pp.
1627–1631.
Stephan, K. L., Smith, S. E., Martin, R. L., Parker, S. P. &
McAnally, K. I. (2006), ‘Learning and retention of associations
between auditory icons and denotative referents: Implications for
the design of auditory warn- ings’, Human factors 48:2,
288–299.
Wiese, E. E. & Lee, J. D. (2004), ‘Auditory alerts for
in-vehicle informa- tion systems: The effects of temporal conflict
and sound parameters on driver attitudes and performance’,
Ergonomics 47:9, 965–986.
— 28 —
Appendices
A The chimes - sound files
In the printed report the chimes can be found on the CD in the
back. In the pdf-document the files are available by clicking the
items below.
1. Info1 19. Info1 with Background noise 1 2. Info2 20. Info2 with
Background noise 1 3. Info3 21. Info3 with Background noise 1 4.
Info4 22. Info4 with Background noise 1 5. SB1 23. SB1 with
Background noise 2 6. SB2 24. SB2 with Background noise 2 7. SB3
25. SB3 with Background noise 2 8. SB4 26. SB4 with Background
noise 2 9. PB1 27. PB1 with Background noise 2
10. PB2 28. PB2 with Background noise 2 11. PB3 29. PB3 with
Background noise 2 12. PB4 30. PB4 with Background noise 2 13. FCW1
31. FCW1 with Background noise 1 14. FCW2 32. FCW2 with Background
noise 1 15. FCW3 33. FCW3 with Background noise 1 16. FCW4 34. FCW4
with Background noise 1 17. Background noise 1 18. Background noise
2
— I —
Info2
null
Instrumental
1.253877
Info3
null
Instrumental
0.8097957
SB2
null
Instrumental
6.060424
SB3
null
Instrumental
6.295527
SB4
null
Instrumental
4.858786
PB1
null
Instrumental
1.5673463
PB2
null
Instrumental
0.6791835
PB3
null
Instrumental
1.253877
PB4
null
Instrumental
4.8849087
FCW1
null
Instrumental
2.6383688
FCW2
null
Instrumental
1.7240809
FCW3
null
Instrumental
1.306122
FCW4
null
Instrumental
2.1159177
null
Instrumental
4.048987
null
Instrumental
4.048987
null
Instrumental
4.048987
null
Instrumental
4.0751095
null
Instrumental
10.396728
null
Instrumental
10.05714
null
Instrumental
10.318361
null
Instrumental
10.266117
null
Instrumental
8.803281
null
Instrumental
8.829403
null
Instrumental
8.829403
null
Instrumental
8.933891
null
Instrumental
6.5045075
null
Instrumental
6.4000173
null
Instrumental
6.4522624
null
Instrumental
6.53063
Info1
null
Instrumental
0.39183667
Info4
null
Instrumental
1.2799995
SB1
null
Instrumental
6.765733
Listening test of Tones Age: _______ Man Woman
Do you have any hearing disorder? What kind?
________________________________
Earlier experience of listening tests?
_________________________________________
The listening test will take about 5 minutes. Thank you for your
time! Josefin Grönlund You will now listen to four different
sounds. Your task is to judge the sound by the word premium.
Premium is here defined as high quality and luxury. Mark your
judgment of the four sounds (A-D) on the following pages. Start the
sounds by clicking on the letters. You may listen as many times as
you need. Then mark your opinion of the sound with a cross in the
eligible square. E.g. Put a cross in the square above the zero if
you think that sound A does not sound
premium at all. If you on the other hand think that sound A sounds
pretty much premium, put a cross in the eligible square between
five and ten.
Premium
Not at all Extremely
Sound A 0 1 2 3 4 5 6 7 8 9 10 Not at all Extremely
Sound B 0 1 2 3 4 5 6 7 8 9 10 Not at all Extremely
Sound C 0 1 2 3 4 5 6 7 8 9 10 Not at all Extremely
Sound D 0 1 2 3 4 5 6 7 8 9 10
II
B LISTENING TEST OF TONES
You will now compare the sounds, two at a time. Listen to the
sounds once more, or as many times as you need. Mark with a ring
the one of the pair that you think sounds the most premium.
Comparison of most ”Premium”:
A or B
B or C
C or D
B or D
A or C
A or D
C Plots of the acoustical quan- tities
Figure 7: Plot of acoustical quantities for FCW1. —– Left channel -
- - Right channel —– Both channels
— IV —
C PLOTS OF THE ACOUSTICAL QUANTITIES
Figure 8: Plot of acoustical quantities for FCW2. —– Left channel -
- - Right channel —– Both channels
Figure 9: Plot of acoustical quantities for FCW3. —– Left channel -
- - Right channel —– Both channels
— V —
C PLOTS OF THE ACOUSTICAL QUANTITIES
Figure 10: Plot of acoustical quantities for FCW4. —– Left channel
- - - Right channel —– Both channels
Figure 11: Plot of acoustical quantities for PB1. —– Left channel -
- - Right channel —– Both channels
— VI —
C PLOTS OF THE ACOUSTICAL QUANTITIES
Figure 12: Plot of acoustical quantities for PB2. —– Left channel -
- - Right channel —– Both channels
Figure 13: Plot of acoustical quantities for PB3. —– Left channel -
- - Right channel —– Both channels
— VII —
C PLOTS OF THE ACOUSTICAL QUANTITIES
Figure 14: Plot of acoustical quantities for PB4. —– Left channel -
- - Right channel —– Both channels
Figure 15: Plot of acoustical quantities for SB1. —– Left channel -
- - Right channel —– Both channels
— VIII —
C PLOTS OF THE ACOUSTICAL QUANTITIES
Figure 16: Plot of acoustical quantities for SB2. —– Left channel -
- - Right channel —– Both channels
Figure 17: Plot of acoustical quantities for SB3. —– Left channel -
- - Right channel —– Both channels
— IX —
C PLOTS OF THE ACOUSTICAL QUANTITIES
Figure 18: Plot of acoustical quantities for SB4. —– Left channel -
- - Right channel —– Both channels
Figure 19: Plot of acoustical quantities for Info1. —– Left channel
- - - Right channel —– Both channels
— X —
C PLOTS OF THE ACOUSTICAL QUANTITIES
Figure 20: Plot of acoustical quantities for Info2. —– Left channel
- - - Right channel —– Both channels
Figure 21: Plot of acoustical quantities for Info3. —– Left channel
- - - Right channel —– Both channels
— XI —
C PLOTS OF THE ACOUSTICAL QUANTITIES
Figure 22: Plot of acoustical quantities for Info4. —– Left channel
- - - Right channel —– Both channels
Figure 23: Plot of acoustical quantities for background noise 90
km/h. —– Left channel - - - Right channel —– Both channels
— XII —
C PLOTS OF THE ACOUSTICAL QUANTITIES
Figure 24: Plot of acoustical quantities for background noise
"Start". —– Left channel - - - Right channel —– Both channels
— XIII —
XIV
Test of Information- and warning chimes
Age:_________ Man Woman
What car do you drive?
_________________________________________________________
If you do not drive a Volvo: Would you consider driving a
Volvo?
Yes No
Do you have any hearing disorder? No Yes What kind?
________________________
• Try to imagine the situation of driving a car and listen to the
sounds.
• Follow the instructions, and follow your first feeling and answer
as sincerely as possible.
• Take one page at a time. • Tell the test leader if you want to
listen to a sound once more.
• After some of the sections there are some lines where you can
write down any comments
you may have.
• The test will take 30-40 minutes. Thank you for your time! /
Josefin Grönlund
D LISTENING TEST ON CHIMES
XV
1. What do you think the sound intends to warn or inform about?
Write what you think the sound intends to warn or inform about?
Different sounds can have the same meaning. Go on to the next sound
if any sound is too hard to define. Sound
A_____________________________________________________________________
Sound
B_____________________________________________________________________
Sound C
____________________________________________________________________
Sound D
____________________________________________________________________
Sound
E_____________________________________________________________________
Sound
F_____________________________________________________________________
Sound G
____________________________________________________________________
Sound H
____________________________________________________________________
Sound I
_____________________________________________________________________
Sound J
_____________________________________________________________________
Sound
K_____________________________________________________________________
Sound
L_____________________________________________________________________
Sound M
____________________________________________________________________
Sound N
____________________________________________________________________
Sound O
____________________________________________________________________
Sound
P_____________________________________________________________________
XVI
2. Which degree of warning do you think the sound belongs to? Mark
with a cross the degree of warning that you think the sounds (A-P)
fits the best. Information Reminder Warning low Warning high
Sound A
Sound B
Sound C
Sound D
Sound E
Sound F
Sound G
Sound H
Sound I
Sound J
Sound K
Sound L
Sound M
Sound N
Sound O
Sound P
XVII
1 2 3 4 5 6 7 8 9 10
Worst practice / Very bad
Average Better than average /
Best practice
3.a Premium You will now hear different sounds. Your task is to
judge how well the sound matches the word Premium. Premium is here
defined as luxury and quality. Pay no attention to the meaning of
the sound, just listen to how it sounds. Mark your judgment with a
cross in the eligible square.
Premium
1 2 3 4 5 6 7 8 9 10 Sound A Sound C Sound D Sound E Sound F Sound
G Sound H Sound I
Sound L Sound M Sound O Sound P
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
XVIII
4.1.1.a Parking brake pulled These four sounds announce that the
parking brake is pulled. Your task is to judge how well the sound
fits with the statement to the left of the grading line. Mark your
judgment with a cross in the eligible square.
Sound E
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
Sound G
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
Sound P
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
Sound D
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
4.1.1.b What do you think makes a sound suitable for announcing
that the parking brake is
pulled?______________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
4.1.1.c What do you think makes a sound not suitable for announcing
that the parking brake is
pulled?______________________________________________________________________
XIX
4.1.2.a Information These four sounds announce that there is
information to read. Perform this section in the same way as
section 4.1.1.a.
Sound A
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
Sound I
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
Sound L
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
Sound F
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
4.1.2.b What do you think makes a sound suitable for announcing
that there is available
information?__________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
4.1.2.c What do you think makes a sound not suitable for announcing
that there is available
information?__________________________________________________________________
XX
4.1.3.a Seat belt reminder These four sounds announce that the seat
belt is not fastened. Perform this section in the same way as
section 4.1.2.a
Sound C
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
Sound H
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
Sound M
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
Sound O
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
XXI
4.1.4.a Forward collision warning These four sounds announce
forward collision warning. Perform this section in the same way as
section 4.1.3.a.
Sound J
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo Frightening
Attract attention
Sound N
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo Frightening
Attract attention
Sound K
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo Frightening
Attract attention
Sound B
1 2 3 4 5 6 7 8 9 10 Suits the sound category
Suits a Volvo Frightening
XXII
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
E Plots of the result from the lis- tening test
Figure 25: Plot of the grade of suitability as a Information
chime.
Figure 26: Plot of the grade of suitability as a Seat belt
reminder.
— XXIII —
E PLOTS OF THE RESULT FROM THE LISTENING TEST
Figure 27: Plot of the grade of suitability as a Parking brake
chime.
Figure 28: Plot of the grade of suitability as a Forward collision
warning.
Figure 29: Plot of the grade of suitability in a Volvo for
Information chimes.
— XXIV —
E PLOTS OF THE RESULT FROM THE LISTENING TEST
Figure 30: Plot of the grade of suitability in a Volvo for Seat
belt re- minders.
Figure 31: Plot of the grade of suitability in a Volvo for Parking
brake chimes.
— XXV —
E PLOTS OF THE RESULT FROM THE LISTENING TEST
Figure 32: Plot of the grade of attention grabbing for Forward
Collision Warnings.
Figure 33: Plot of the grade of frightening for Forward Collision
Warnings.
— XXVI —