Download A Weakly Intrusive Ambient Soundscape for

A Weakly Intrusive Ambient Soundscape for
Signaling and Intuitive State Perception
Fredrik Kilander & Peter Lönnqvist
Department of Computer and Systems Sciences, Stockholm University/KTH
Electrum 230, SE-164 40 Kista, Sweden
{fk, peterl}@dsv.su.se
Introduction
The use of audio cues in computer interfaces has
seen a remarkable development in recent years with
the general proliferation of soundcards and sound
sources. The audio schemes in the Microsoft Windows operating systems, for example, offer the
association between a rich set of system events and
sounds. The events most commonly encountered
are, perhaps, login and logoff events, notification of
new email and the proverbial beep when something
goes wrong. All these events, however, are closely
tied to events and changes of state which are either
obvious anyway, or without sufficient resolution to
avoid being a nuisance.
In this paper we present WISP, the concept
of an ambient soundscape in which events and
states in the computing and physical environment
are reflected in the form of next to non-intrusive
audio cues. A WISP is meant to service a physical
space, like a personal office or a common room.
The listening experience is intended to convey
intuition rather than interruption; each signal should
be sufficiently non-intrusive to be accepted without
disturbing the focus of the task at hand, while distinctive enough to be separable from the other cues.
The selection of auditory messages that humans choose to process can be seen as depending
on context rather than physical characteristics (Anderson, 1995). At a cocktail party we can follow
one conversation, but as we hear our name mentioned in another conversation our focus is suddenly changed. Thus we can say that auditory messages that bear meaning are the ones grasping our
attention. Meaning in this sense might not always
be mapped to semantics, but might as well be
learned. For instance, when the sound of the telephone is heard, we know that someone probably are
calling us. Auditory messages of this type are often
quite disturbing, and it is also their intention to be
so, to be able to grasp our attention. We propose
more non-intrusive auditory messages and predict
that if we map meaning to these they might be just
as useful without disturbing the user in the same
way as a phone signal might do, and they might
even be comfortable to listen to.
Choosing sounds
For our prototype we elected to work with natural
sounds. We recognize that human reaction to sound
is individual and culturally motivated, it is therefore
important to emphasize that no particular set of
non-intrusive natural sounds is a priori more suitable than others. Still, we believe that the selection
of natural sounding soundscapes can be narrowed
down to an environment in which the WISP is not
perceived as noise pollution.
In order to provide support for both discrete
events and long-term state intuition, we are interested in both short sounds and backdrops which can
be conveniently looped without sounding artificial.
Short sounds, i.e. sounds with discrete playback
times, can of course be quite long. The sound of
rolling thunder, for example, may be of several
seconds duration.
As a starting point we explore the sounds of
the forest. These include many possible variations
which include both natural and manmade audio
cues. Birdcalls from various species, insects, the
sound of wind, rainfall and thunder are all immediately available. Manmade sounds include trains,
planes and automobiles passing in the distance as
well as church-bells and the occasional far voice,
although the latter two are probably to craving of
attention to be non-intrusive.
Before we go on to the usage of these sounds
in a WISP, we should recognize other soundscapes
of interest. The sounds of a city provide a powerful
backdrop on which to project suitable signals: traffic, car horns, passing music, dogs etc. Likewise,
the seashore, a train station or an airport should
provide interesting avenues of exploration. Common to these manmade environments is that they
are generally much more noisy than a forest, which
may work to be counter the intended effect of the
WISP, namely that it should not pollute the natural
environment.
A personal WISP in use
In this section we will sometimes assume that
availability of a localizer service that can be queried for the location of people. The WISP concept
is no way dependent on such information, but the
particular application we like to use in the example
is.
Co-worker presence
We could, for example, associate the presence of
selected co-workers with certain bird calls and
playback frequencies. The net effect is that as more
and more colleagues arrive at work, the WISP forest fills up with birds. Rather than consciously
watching for a particular sound, the listener is expected to acquire an intuition for the number of coworkers present (and presumably out of sight).
Email inbox state
The simple arrival of yet another mail is in many
cases not reason enough to disrupt ones work.
While the notification may often be welcome, it can
also be perceived as intrusive and stressful. Because of this, we explore the possibility of using the
WISP to convey more information about the waiting mail.
A classifier scans the waiting mail and provides the wisp with categories of email: personal
mail, mailing-list submissions and suspected spam.
Each category then results in a different sound cue
which may be either looped or repeated with a
certain intensity. The net result is that the listener is
bestowed an intuition of the expected contents of
the unread mail, rather than the interruption of each
new message.
A shared WISP
The deployment of a WISP in a shared space, like a
meeting room or kitchen is escorted with issues of
how to join the preferences of several people when
each is to be catered by a single WISP (again we
assume a localization service which tracks the
movement of people within a building). One imme-
diate conclusion is that users of the shared WISP
also subscribe to a shared set of available notifications. In this way, each notification is associated
with a single sound, forcing listeners to share sound
cues. This greatly reduces the possibility that users
confuse a certain cue with different semantics. It
also allows the WISP to join events directed at
several subscribers into a single playback event.
Another property of a shared WISP is that it
becomes a broadcast environment. With the sound
available for everyone to hear it becomes difficult
to aim particular cues at a single person. This in
turn makes it important to look at the risk of the
WISP as a source of noise pollution. For example,
when a group which does not subscribe to the
services of a present WISP suddenly is joined by a
heavy subscriber, the group may be annoyed by the
sudden presence of audio cues. To counter this, the
WISP should allow users to be subscribers to silence as well as sound.
Technology
We have implemented a simple WISP in Java. The
audio playback features of JDK 1.2 offers simultaneous playback of up to 64 channels of sampled
sound (or MIDI data which we do not use). At the
time of this writing an email state provider is being
prepared.
References
Anderson, J. R., (1995), Cognitive Psychology and
its Implications (Fourth Edition), New York: W.H.
Freeman and Company.
Ishii, H., Wisneski, C., Brave, S., Dahley, A., Gorbet, M., Ullmer, B., and Yarin, P., ambiemtROOM:
Integrating Ambient Media with Architectural
Space, in Proceedings of CHI '98, ACM, New
York, pp. 173-174.