S
uccess or failure in building the ulti-
mate home theater often hinges on the
spouse factor. How much will your signifi -
cant other allow you to spend? How many
wires will he or she tolerate snaking across
the living-room fl oor? How many speakers
can you mount on the walls before your bet-
ter half issues a cease-and-desist order?
Well, what if building the audio portion
of a high-end home-theater system meant
purchasing and installing just one device?
Wouldn’t that go a long way toward disarming
your spouse’s argument against a home the-
ater? Digital audio-projector (DAP) technology
promises to make this seemingly impossible
dream a reality. It enables a manufacturer to
enclose a multi-channel amplifi er, a surround-
sound decoder, a speaker array, and confi gu-
ration software in a single cabinet.
By projecting sound waves to specifi c
locations in a room, much like a stage ven-triloquist “throws” his
voice, a digital audio
projector can fool
your ear into believing
that sound events are
emanating from vari-
ous locations inside
a room—to the left,
right, center, or rear
of your head—even
though they’re actu-
ally originating from a
single source.HOW DIGITAL
AUDIO
PROJECTORS
OPERATE
British manufacturer
1 Ltd. has done much
of the pioneering
research and develop-
ment to make digital
audio projectors pos-
sible, and consumer
electronics manufac-
turers Pioneer and
Yamaha are the fi rst
companies to incor-
porate 1’s technology
into retail products.
Yamaha’s YSP-1,
introduced at the 2005 Consumer Electron-
ics Show, has garnered the lion’s share of
attention, thanks to the fact that it retails for
$1,500; Pioneer’s PDSP-1 digital sound pro-
jector, introduced back in 2003, is saddled
with an astonishing $40,000 price tag.
1 Ltd.’s Digital Sound Projector chipset
consists of two compo-
nents: A digital signal
processor (DSP) that the
company has dubbed the
Beam Forming Proces-
sor Chip, and a digital
Class D amplifi er. The
beam-processor chip
decodes surround-sound
algorithms, such as
Dolby Digital and DTS.
It’s capable of process-
ing up to eight channels
of audio and converting
them into “beam-forming”instructions for as many as 256 transducer-
type speakers. The amplifi er takes these
instructions and plays them through the ap-
propriate speakers to create the illusion of
surround sound.
It’s vital that the digital audio projector
be calibrated for the shape and size of your
listening environment. Once that’s done and
an audio source, such as a DVD player, is
connected to the system, the DAP is ready
to create its audio illusions.
In a surround-sound confi guration, the
DSP chip forms unique audio beams by split-
ting and routing the audio signals to select
groups of speakers within the projector. By
taking the shape of the room into account,
the DSP inserts a delay for each speaker and
makes micro adjustments to the output of
each amp to create fi ve distinct audio beams:
left front, right front, center, left surround, and
right surround. By directing these beams along
tightly focused paths and using the wallsr & d BREAKING DOWN TECH —PRESENT AND FUTURE
58 MA XIMUMPC OCTOBER 2005
White Paper: Digital Audio Projectors
Using acoustic tricks that
would be familiar to a skilled
ventriloquist, a digital audio
projector can beam audio
around a room to duplicate
the impact of a 5.1-channel
surround-sound system
BY JOEL DURHAM JR.Yamaha’s YSP-1 digital audio projector ($1,500) uses DSP
technology and 42 individual speakers (visible here with the
grill removed) and amplifiers to replace a 5.1-channel A/V
receiver and surround-sound speaker setup.HOW IT WORKSHOW IT WORKS
ÑA digital audio projector (DAP) uses an array of small speakers and amplifi ers, coupled
with a powerful digital signal processor, to “beam” audio signals around a room (as
illustrated by the blue shaded areas above). By bouncing the audio off a room’s walls and
ceiling, the DAP fools the listeners’ ears into believing that sounds are emanating from
specifi c locations.The setup in a typical room
Location
of DAP
unit