PROCEEDINGS of the23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Characterization of the indoor kitchen soundscapePieter THOMASa, Luc DEKONINCKa, Stephanie VAN HOVEb, Anissa ALLb, Peter CONRADIEb,
Lieven DE MAREZb, Henk HUISSEUNEc, David PLETSa and Dick BOTTELDOORENaab

WAVES, Ghent University, Belgium

imec-mict, Ghent University, Belgiumc

NOVY nv, Belgium

ABSTRACTWith a growing tendency for compact living, the kitchen space is typically at the center of the daily activity,
combining different functionalities. In the context of the ”IoT chef” project, the cooking experience isoptimized, with focus on the cooker hood noise. In a first part of the study, a large-scale online survey (N =754) is conducted among Flemish home cooks in order to (1) map personal assessments of the soundenvironment during a typical cooking experience and (2) evaluate the indoor (kitchen) soundscape based on
the ISO 12913-1/2 standard. The impact of the role of the observant (chef or bystander) on the subjective
evaluation is investigated. In a second part of the study, typical kitchen sound levels are monitored during aone-week period at 16 households, selected from survey participants. Additionally, cooker hood levels aremeasured at the cook’s ears to define the contribution of hood noises in the overall kitchen soundenvironment. Results from the measurement campaign are presented and discussed.
Keywords: Indoor Soundscape, Kitchen, Cooker Hood

1. INTRODUCTION
Today, the product sound quality of many different types of products including vehicles andhousehold appliances is carefully designed [1]. Their sound often contributes to the branding of theproduct [2]. Some products however do not produce a dominant sound while in use. On the contrary,
their sound is expected to blend into the overall sonic environment without a ttracting much auditory
attention [3]. Yet they could still contribute to the overall soundscape; the sonic environment asperceived and understood by people within context [4] even in a subliminal way. Some of theseproducts are always found in a similar context or at least this is commonly assumed. The kitchen hoodis an example of such an appliance. Low noise level is an important discriminating factor betweenhoods, yet the characteristics of the sound leading to energetic or perceptual masking have not been
investigated. To understand the interaction of this device with its environment and to be able to design
its sound, the typical surrounding soundscape and the variety of soundscapes corresponding to various
types of kitchens and household types must be understood. Kitchen sound environment is not the only
reason to address the issue of kitchen hood sound. Reduced use of the kitchen hood due to its negative
impact on the sound environment may lead to higher pollution levels with potential health impact.
Thus, several research questions were formulated: (1) are people generally satisfied with the soundenvironment in their kitchen; (2) to what extend does the kitchen hood contribute to this appreciation;(3) what is the effect of personal sensitivity? To answer these questions, in the IoTChef project, abroad questionnaire survey was conducted that amongst others enquired about the soundscape using astandardized approach [cite ISO12913 part 2]. In addition, a focused survey was conducted with asubgroup of 27 households. In this focus group, questionnaires were complemented wi th physicalobservations and measurements.

2. METHODOLOGY
2.1 Broad survey
A survey on cooking experience was conducted online with a panel of volunteers that were4154

previously recruited by imec-mict for consumer research. As part of the survey, four questions related
to sound were included:(1) a standard noise annoyance question [Error! Reference source not found.] slightly modified
to reflect the context of the kitchen (freely translated from Dutch) “Think about an ordinary
evening in the kitchen. Describe how you experience the kitchen as sound environment. To
what extend are you annoyed or not annoyed by the sound of [vocal sounds of people,
non-vocal sounds of people, sound of pet animals, installation sounds, operational sounds,electronic sounds, environmental sounds]?” For each category a few examples are given and afive-point standard answering scale is provided.
(2) An overall appreciation of the sound environment according to the circumflex model [7] which
after the same leading context sketch as above reads “The sound environments is [pleasant,comfortable; chaotic, complex; fascinating, stimulating; immobile, passive; calm, tranquil;
irritating, annoying; active, lively; monotonous, uninteresting]” Again a five-point answering
scale is provided.
(3) A general appreciation on the sound environment with five answering categories from very
good to very bad.
(4) A noise sensitivity question, the 10-item Weinstein scale [8].
In total 754 participants answered the survey, 330 female, 424 male and with and age range 18 to 70years.
2.2 Focus group
Volunteers (16) were selected from the survey that were willing to participate in an in-depth studyof their kitchen habits. For this reason, an in-depth interview was conducted with these volunteers. In
addition, activities in the kitchen were video-recorded and noise and air quality were monitored over a
period of one week. This study was approved by the ethical committee of UGent and participants were
duly informed about the purpose of these recordings.
For soundscape observation, the microphone was placed at ear height in a corner of the kitchen. A
black carbon aethalometer is used to evaluate the air quality in the kitchen.

3. RESULTS
The soundscape evaluation from the broad study (question (3)) is treated as a continuous scale andresponses are averaged. This gives an average score on each of the eight dimensions that is shown in
Fig. 1. Standard deviations over the population of respondents are similar for each dimension andamount to slightly under one unit. On average the kitchen soundscape at home is evaluated as pleasantand comfortable, qquite calm and tranquil,
but also active and lively.
qyFigure 1 – Spider graph of kitchen soundscape evaluation.

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Although most participants indicate a positive valence of the soundscape, it is worth analyzing thecontribution of various possible sounds that could be heard in the kitchen to the negative valence(annoyance). Therefore, the first sound related question is analyzed (1). Figure 2 shows reported
annoyance by different categories of sounds. In general, the percentage of the respondents that reportmoderate to high noise annoyance is low and there is not much distinction between sources. Although
the relatively high percentage of annoyance by sounds of pets is worth mentioning, we further focus on
installation sounds and operational sounds. 11.9% of the respondents is at least moderately annoyed by
the sounds of installations (e.g. ventilation, kitchen hood) while 13.7% is at least moderately annoyedby operational sounds (e.g. microwave, oven, blender).
On the other hand, 55% of respondents mention in another part of the survey that the noise level isa very important criterium when buying a new kitchen hood. This makes it the criterion that is selectedby the highest number of respondents as very important, more so than suction power and energy
efficiency.

Figure 2 – Percentage of the respondents that indicate that they are annoyed by the different categories ofsounds for several degrees of annoyance.
As it is well known that personal factors (and in particular noise sensitivity) influence noise
annoyance it is worth investigating the correlation between the responses on the noise annoyancequestions and the personal noise sensitivity as evaluated using the Weinstein questionnaire; soundquestion (3). The sum of responses on the sub-questions (including a sign switch where needed) is asignificant predictor for all noise annoyance questions. However, it should be mentioned that also theanswer on the questions on annoyance by sound produced by people is a good predictor for the answer
on the question on annoyance by installation or operational sounds. The latter even produces a slightly
better linear regression model.

4. DISCUSSION
For putting kitchen hood sound in a context where it is usually perceived, kitchen soundscapes wereinvestigated. This showed that people perceive the sound environment in their kitchen generally as
pleasant and calm and tranquil or lively and active. All of these factors have positive valence. Thismay be explained by a strong feeling of control on the sound environment perceived in this context[cite reference on control]. In addition, the relatively strong contribution of own sounds duringcooking may reduce the probability of noticing potentially disturbing sounds [9]. The observation thatenvironmental sounds from outside the kitchen (cars, trains, planes) cause high annoyance only for 1%of the respondents – while government surveys show values of up to 10% - may confirm thisobservation.
Moreover, it could be observed that installation sounds and operational sounds, both mechanicalsounds produced by e.g. the kitchen hood, blenders, ovens, contribute to noise annoyance. However,these sounds affect a similar percentage of the respondents as other sounds that could be heard in thekitchen context such as pets and humans or sound from outside. It is known since long that noise4156

sensitivity is a stable personality treat that may influence the effect of noise on people [10]. It is partly
inherited and may influence the way the human brain analysis the auditory scene [11]. Hence, it is notunexpected that a significant percentage of the reported noise annoyance is explained by noise
sensitivity and therefore does not depend strongly on the noise source : a small percentage of very
sensitive people will experience any additional sound as annoying.

5. CONCLUSIONSThe kitchen soundscape was analysed with a focus on the contribution of installation sound andoperational sound. This puts the design of kitchen appliances in a clearer context where sound quality
may be less important than their contribution to noise annoyance. Nevertheless , some further analysisof the focus group study should reveal whether particular components of the sound contribute more to
this annoyance.

ACKNOWLEDGEMENTS
This work was performed within IoT Chef, a project co-financed by imec and receiving project
support from Flanders Innovation & Entrepreneurship.

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