I’ll get that to go: HyperSonic Sound technology and the right to be left alone
By: Catherine Thompson
July 12, 2005
a technology that would have the ability to focus sound in a beam,
rendering it inaudible to all but a few select individuals. Now imagine
enabling communication between this technology and existing
identification technologies, such as RFID. The result: direct
advertising in public spaces. While such technologies are interesting
to ponder from a marketing perspective, there is no need to ponder them
from the perspective of the technologies. HyperSonic Sound technology
(HSS) already exists.
1. What might the deployment of such technologies mean for anonymity?
Westin defines anonymity as occurring “when the individual in is public
places or doing public things but still seeks, and finds, freedom from
identification and surveillance.” Westin also noted in his seminal 1967
work, Privacy and Freedom,
that privacy in part serves to distinguish those places and times when
we are supposed to socialize. Despite our desire to be left alone in
public, we also desire to socialize. However, if we learn to fear
entering the public sphere as a consequence of HSS technology, we could
suffer diminished civil life participation.
HSS was developed by the American Technology Corporation.
It calls HSS “the most revolutionary sound reproduction system of this
century.” The technology is able to focus sound into a beam like light
from a flashlight. The applications are numerous, but one vision is the ability to directly speak to specific individuals in a crowd. As its website
says, “[t]hink about the ability to focus sound into a crowd of people
on a football field and talk only to a selected few.” Put in terms of
its marketing potential, as one journalist describes,
“[m]otion-sensitive HSS emitters can flog Doritos on one end of the
snack aisle and hawk Cracker Jack on the other.” [Christopher Helman,
“Now Hear This” Forbes 172:5 (September 2003)]
now, we have had to rely on loudspeakers and their decibel settings to
get a message across a large space. However, scientists have found a
way to control sound waves in the air from far away. HSS itself is
beyond human hearing until it hits a surface. Accordingly, when the
beam is focused on an individual, she or he hears only the sound around
her or his head -- and not from any particular direction. A reporter
describes what HSS technology is like: “Suddenly I heard the sound of
birds chirping. The noise didn’t seem to emanate from his device; I
felt like it was generated inside my noggin.” [David Sparrow,
“Hypersonic Sound” Popular Science 261:6 (December 2002)]. Another journalist had a similar description:
flicks a switch on an ordinary looking amplifier, and you become
vaguely aware of a tinny beat, as though there's someone on the other
side of the room listening to salsa music on leaky headphones. Then he
swings the disc towards you, until you're facing it full on, and
something extraordinary happens. The air around your head explodes with
music. It's as if the Buena Vista Social Club has sneaked up behind you
and burst into action. [He] motions for you to walk towards the disc.
You take a few steps forward, and the music follows you like a swarm of
bees. Then he tilts the disc away and the sound blips out of existence.
[Graham Lawton, “They’re playing my tune” New Scientist 167:2255 (September 2000)]
3. Who will use HyperSonic Sound technology?
are one potential user of the technology. As one reporter puts it:
“Marketers have always dreamed of whispering into the ears of
individual shoppers.” [Helman]. The American Technology Corporation says
HSS emitters are not for sale to the general public: “Please note, the
current S220A is targeted towards professional, commercial, and point
of sale applications. This model is not intended as a consumer
product.” However, my On the Identity Trail colleague Alex Cameron recently sent me a link to an HSS emitter being sold on E-Bay
available for purchase without restriction to the highest bidder.
Therefore, it is unclear who will be using HSS emitters in the future
or how its use will be controlled.
4. American approach: The right to be left alone in public spaces
The U.S. Constitution’s First Amendment protects freedom of speech.
However over time, American judges have carved out another right to be
balanced against it; the right to be left alone in public spaces.
first cases to do so began in the late 1940s with what was then a new
technology: the loudspeaker. Many municipalities banned their use in
public spaces and the constitutionality of those by-laws was challenged
by loudspeaker owners. Although the right did not gain ground in its
first case (Saia v. New York, 1949), the justices in the minority raised the issue by saying:
devices for amplifying the range and volume of the voice, or its
recording, afford easy, too easy, opportunities for aural aggression.
If uncontrolled, the result is intrusion into cherished privacy. The
refreshment of mere silence, or meditation, or quiet conversation, may
be disturbed or precluded by noise beyond one’s personal control.
cases developed under the more general heading of ‘captive audience
cases.’ The 1974 case of Lehman v. City of Shaker Heights traced the
concept back to a 1932 statement made by Warren Brandeis in Packer
Corp. v. Utah: “[t]he radio can be turned off, but not so the billboard
or street car placard.” In other words, the right to speak must involve
a willing audience, not a captive one. If the listener is not able to
decline listening to the message, that will violate the individual’s
right to be left alone. In the loudspeaker context, the balance struck
with free speech saw loudspeaker use continue, but also limited with
regards to the type of area the broadcasting occurred. For example,
loudspeaker use can be restricted to daytime hours if it is within
earshot of a residential area (Kovacs v. Cooper, 1949). It has yet to
be seen what kind of balance would be struck in the case of HSS
5. Canadian law
the United States, Canadian Constitutional protection of rights does
not extend to the private sector. Therefore, if HSS technology became
popular in Canada, the government could not prevent its use on that
basis. Even if Constitutional rights were extended to include the
private sector, we do not have a similar right to be left alone in
public spaces that we could enforce.
has private sector legislation aimed at restricting the collection, use
and disclosure of personal information in the marketplace. However, it
is not clear whether these laws could the prevent HSS technology from
being used, even if the message emitted is tailored through the
collection of your information without consent. More interesting is
whether we can prevent the collection and use of information we send
out by the very fact of being human. As Gary Marx says:
To be alive and a social being is to automatically give off signals of
constant information – whether in the form of heat, pressure, motion,
brain waves, perspiration, cells, sound olifacteurs, waste matter, or
garbage, as well as more familiar forms such as communication and
visible behaviour. [Colin J. Bennett & Rebecca Grant, eds., Visions of Privacy: Policy Choices for the Digital Age (Toronto: University of Toronto Press, 1999) at 40].
sector legislation protects information about an identifiable
individual. For example, telephone numbers are considered personal
information because they can be easily linked with a particular
individual [Case 99].
However, if an emitter is able to determine that you are a middle-aged,
Armani suit wearing male with the flu, an ad could target you without
the technology identifying you specifically. This would not meet the
definition of personal information.
principles underlying privacy and anonymity would suggest that there is
something worth protecting here. The American approach is able to do so
by maintaining a sphere of privacy around the individual. Canadian
legislation, on the other hand, protects data and is therefore not
always able to fit itself to new data flow or technological scenarios.
Commissioners and lawmakers should keep this in mind, not only with
regards to current assessments of potentially privacy invasive
technologies, such as RFIDs and HSS, but also vis-à-vis technologies
that have yet to be imagined. Normative fences around individuals are
the most stable way to ensure consistent privacy protection in the
I would like to thank Prof. Kerr for all his enthusiasm and encouragement. I would also like to thank Chris Hoofnagle, Associate Director of the Electronic Privacy Information Center, for first alerting me to this new technology.