A
bout a year and a
half ago, I got my
first taste of Phase
Technology’s remarkably ad-
vanced and utterly unforget-
table DARTS speaker system,
whose name is an acronym
that stands for Digital Audio
Reference Theater System.
The self-powered, DSP-con-
trolled system was something
of a technical marvel, and it
even offered a fuzzy logic-
driven room EQ system de-
signed to optimize response
across multiple listening lo-
cations at once. Since I come
from the “simpler is better”
school of thought, I am some-
times skeptical of technically
complicated solutions, but I
had to admit that the DARTS
system sounded extremely
transparent and that its
high-tech EQ system really
worked. “A future TPV review
subject,” I thought to myself.
Now let’s fast-forward
to the 2006 CEDIA show,
where Phase Technology
announced the new DARTS
525 system, which in 5.1-
channel configuration sells
for between $11,000 and
$12,800 (depending upon
whether you want one sub
or two). The system price
buys you 5.1-channel’s worth
of speakers plus a powerful
DSP-controlled, 16-channel
Class D amplifier. Sixteen
channels are needed be-
cause the DARTS 525 system
powers each individual
speaker drive unit (or set
of drive units) with its own
amplifier channel. Don’t be
fooled by the tiny 525 main
speakers, though, because
there is nothing miniature
about this system’s sound.
The DARTS 525 system con-
sists of two 2-way biamplified
DFS-525LR main speakers, a
3-way triamplified DFS-525C
center channel, two bipolar/
dipolar biamplified DCB-
SURR surround speakers, a
pair of 500-watt DCB-112S
powered subwoofers, and
a DP-2000 DSP-controlled
16-channel Class D power
amplifier that cranks out
250Wpc. We describe the dis-
tinctive technologies and set-
up procedures used for the
Self-Powered, DSP-Controlled, 5.1-Channel Speaker System
Phase Technology DARTS 525:
Better Music Through Science
by Chris Martens
ECHNOLOGY FOCUS
DFS-525C center channel
Electronically reprinted from March 2007
"The self-powered,
DSP-controlled system
was something of a
technical marvel"
"It's an
addicting
experience"
Phase Technology
dARTS 525
Speaker System
DARTS system in two side-
bars, but for now let’s focus
on how the system performs.
Clarity Comes First
Right off the bat the DARTS
525 system bowls listen-
ers over with its stunning
openness and transparency.
With many AVRs and some
A/V controllers, I’m used to
hearing a certain amount
of low-level hash with DSP
circuits, but in the DSP-con-
trolled DARTS 525 system
I really couldn’t hear any
hash or graininess at all.
What I heard, instead, was
a veritable smorgasbord of
sonic details and textures
spread out as if on a ban-
quet table. With the DARTS
525 rig you’ll want to put on
favorite music recordings and
movies one after another,
just to see if the system will
reveal any cool new pieces
of low-level information you
might have missed before.
It’s an addicting experience.
On movie soundtracks in
particular, I heard low-level
details that often get lost or
buried in other systems. One
good example would be the
shootout scene from Open
Range, which enthusiasts
know for its violent action—
and many sonic subtleties. As
Charlie and Boss face down
their opponents, for example,
you can hear insects chirping
and the prairie wind whis-
tling faintly and mournfully
in the background. Through
the DARTS 525 system these
subtle details become crys-
tal clear and serve—on an
Dish Network | (800) 969-4388 | www.dishnetwork.com/dishhd
In a very real sense the DARTS 525 system
is the brainchild of three companies: Phase
Technology, which contributed speaker/
drive unit design know-how, D2Audio,
which contributed Class D switching
amplifier technology, and Audyssey
Laboratories, which provided a custom-
ized version of its sophisticated MultEQ XT
automated speaker setup/room EQ system.
From the start DARTS 525 was
conceived as a self-powered or “active”
speaker system where individual drive
units would be powered by dedicated
Class D amplifiers, with all traditional
crossover functions handled by digital
signal processing (DSP) engines built
into the amplifier module. One reason the
speaker system performs so well is that
its drive units and amplifiers were literally
designed for each other. D2Audio’s Class
D amplifiers are capable of very wide
bandwidth, nearly grain-free resolution
of textural details, lightning-fast transient
response, and high damping factors
(which describe the amplifier’s ability to
control driver motion without overshoot).
Phase Technology designed the DARTS
525 drive units to take advantage of these
characteristics to the fullest extent possible.
Another advantage is that DARTS 525
is a DSP-controlled speaker system where
output level matching and crossover
frequencies and slopes are controlled in the
digital domain. But the DARTS 525 system
takes DSP further still, applying DSP-driven
frequency and time response EQ curves at
the driver level to yield ruler-flat frequency
response, ideal phase response, and
perfect time alignment between drivers. In
short, DARTS 525 would be a tremendous-
ly accurate speaker system even if it did not
provide automated setup/room EQ features.
But DARTS 525
does
provide those
features, and they add an extra dimension
to the system’s performance. Unlike other
EQ technologies, Audyssey Laboratories’
DSP-powered MultEQ system optimizes
the speaker system’s in-room frequency
and time response characteristics for
multiple listener locations—not just for
one central “sweet spot.” Through a
comprehensive set-up and calibration
process, it gathers room/speaker response
data from multiple seating locations,
collecting as many as 32 complete sets
of measurements. Then, the MultEQ
system applies fuzzy logic techniques to
analyze the data and calculate optimal
frequency and time response correction
filters for each speaker in the system.
The term “fuzzy logic” means that
the Audyssey system does not simply
average response data as some compet-
ing systems do but rather takes the more
sophisticated approach of analyzing data
to identify specific “clusters” or patterns of
response problems within the room. Then,
taking a “whole system” approach, the
system plots channel-specific correction
filters that together work to compen-
sate for room/speaker problems across
multiple listening locations at once. The
DARTS 525 system correction filters are
extremely precise, providing an astound-
ing 512 individual correction points
per speaker, which result in remarkably
smooth in-room response curves.
The real genius of the system is that it
is an exceptionally accurate speaker that
does not try to achieve “perfect” response in
any one room location. Instead, it aims to
achieve very good response at multiple lo-
cations within real-world listening rooms—
a job at which it succeeds brilliantly.
The Technologies Behind the DARTS 525
DFS-525LR main speaker
(in cherry finish)
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almost subliminal
level—to remind
us how terribly
alone and exposed
the cowboys are.
But beyond
finesse, the system
also serves up ex-
plosive dynamics
that seem impos-
sibly powerful
given how small
the DARTS speaker
modules are. The
“Omaha Beach”
scene from Saving
Private Ryan convinced me
the system could at once
play loudly and cleanly,
as it reproduced thunder-
ous explosions with suffi-
cient force to send pressure
waves rippling across the
slab floor of the TPV Audio
Lab. Similarly, the system
made the eerie ping and
whirr of bullet ricochets
sound so immediate and
intense that I felt an invol-
untary urge to take cover.
This system offers more than
enough dynamic head-
room to deliver the goods in
moderately large rooms.
On music, the DARTS 525
system sounded clean, trans-
parent and authoritative,
teasing out the subtle timbres
of individual instruments and
voices, and handling large
and small-scale dynamic
shifts with grace. These
qualities combined syner-
March 2007 The Perfect Vision
tech focus: Phase Technology DARTS 525
Specifications
P
hase Technology DFS-525LR 2-Way,
Biamplified Main Speaker
• Driver complement: One 1" fabric-dome
tweeter, one 5.25" glass/honeycomb
composite mid-bass driver
•
Frequency response: See system re-
sponse specification, below.
•
Sensitivity: 91dB (1W/1m)
• Impedance: Not specified
•
Amplifier power: See amplifier
specifications, below
•
Dimensions: 6.875" x 11.5" x 9.75"
•
Weight: 10 lbs.
Phase Technology DFS-525C 3-Way,
Triamplified Center Channel
As for DFS 525LR above, except for the
following:
• Driver complement: One 1" fabric-dome
tweeter, two 5.25" glass/honeycomb
composite mid-bass drivers
• Dimensions: 18" x 6.875" x 9.75"
•
Weight: 12 lbs.
Phase Technology DCB-SURR Bipolar/
Dipolar, Biamplified Surround Speaker
As for DFS 525LR above, except for the
following:
• Driver complement: Two 1" fabric-dome
tweeters, two 5.25" glass/honeycomb
composite mid-bass drivers
• Dimensions: 10.5" x 15.25" x 4.625"
•
Weight: 12lbs.
Phase Technology DCB-112S Powered
Subwoofer
•
Driver complement: One 12" woofer, two
10" passive radiators
• Integrated amplifier power: 500 Watts
•
Dimensions: 14.5" x 15.5" x 15.5"
•
Weight: 62 lbs.
Phase Technology DP-2000 16-Channel
DSP-Controlled Amplifier
•
Power output: 16 x 125Wpc @ 8 ohms or
250Wpc @ 4 ohms; EQ characteristics for
all channels under DSP-control
•
Number and type of audio inputs:
16 single-ended (via RCA jacks);
USB programming port for onboard DSP
engines
•
Dimensions: 17 " x 5.625" x 17"
•
Weight: 21 lbs.
Phase Technology DARTS 525 System
• Frequency response: 20Hz–20kHz
•
System price: $12,800 with dual
subwoofers (as tested); $11,000 with
single subwoofer
The Last Word
I really couldn’t hear any DSP-induced hash or
graininess at all. What I heard, instead, was a
veritable smorgasbord of sonic details and tex-
tures spread out as if on a banquet table.
[ ]
DP-2000 amplifier
DCB-112S subwoofer
• Striking transparency and focus
• Catches details most systems miss
• Mind-blowing dynamics
• Smooth, neutral tonal balance
• Giant “sweet spot” means all
seats are good seats
• Installation/set-up tools should be
available to end-users
• Should incorporate Audyssey’s
latest upper midrange “contour
controls”
gistically as I listened to the
Oue/Minnesota performance
of the finale of Respighi’s
Pines of Rome [30th Anni-
versary Sampler, Reference
Recordings]. This passage
is famous for the way its
orchestration and dynam-
ics build in intensity toward
a thunderous crescendo—a
crescendo the DARTS sys-
tem captured beautifully.
My only criticisms of the
system are minor. First, the
DARTS system is not the last
word in 3D imaging because
its main speakers occasion-
ally draw too much attention
to themselves on hard,
upper midrange/treble
transients. Second, the sys-
tem can on some material
sound a little too bright,
though I know it measures
very well. This issue could
easily be addressed, I
think, if Phase Technol-
ogy adopts the new upper
midrange “contour control”
that Audyssey Laborato-
ries recently developed
for use in its standalone
room EQ products.
Phase Technology’s
DARTS system is a superb
performer that offers good
value for the money and
provides an eye-opening
glimpse at what I think will
prove to be the future of
loudspeaker system de-
sign. The greatest beauty of
the system, though, is that
it works for multiple listen-
ers at once, creating—as
one Absolute Multimedia
staff member put, “a gi-
ant sweet-spot that seems
to be everywhere.” TPV
www.theperfectvision.com March 2007
Phase Technology | (888) 742-7385 | www.phasetech.com
When DARTS 525 systems
are sold, the dealer sends a
DARTS-qualified installer to the
user’s home to calibrate the
system (the dealer may or may
not charge for this service). The
installer brings a calibration
system consisting of a laptop
equipped with test/calibra-
tion software, a calibrated
microphone, and a special
“umbilical” cord that connects
the laptop to the DARTS 525
system amplifier. The installer
runs a series of laptop-driven
tests (pulsed sweep tones that
are played through each speaker
in succession), taking multiple
measurements from locations in
and near every seat in the room.
Once data gathering is
complete, the installer runs a
computation-intensive, Audyssey
Laboratories-developed com-
puter program that calculates
frequency and time response
correction filters for each speaker
in the system. Phase Technol-
ogy offers users four possible
EQ tuning curves to allow for
rooms that are large or small
and whose acoustics may be
reverberant or dead. For rever-
berant spaces, the system rolls
off upper midrange and treble
response a bit to compensate for
the fact that “live” rooms tend
to make speakers sound overly
bright. Once a preferred EQ tun-
ing curve is selected, the install-
er downloads filter settings to
the amplifier’s DSP engines via
a faceplate-mounted USB port.
As the last step in the set-up
process, the installer discon-
nects the calibration system
and configures the system’s
preamp/multichannel control-
ler to drive the DARTS 525
amplifier. During the data
analysis process, DARTS
calibration software calculates
recommended speaker distance
settings (accurate to with a
tenth of a foot) and channel
level settings (accurate to with a
tenth of a dB). The installer then
connects the controller to the
DARTS amplifier and loads the
recommended settings, at which
point the system is ready to play
music or movie soundtracks
in a way most people have
not experienced before.
DARTS 525 System Setup
Poor Good Excellent
10 2 3 4 5 6 7 8 9 10
Bass Dynamics
Bass Pitch Definition
Bass Extension
Self-Amplified Subwoofers
Poor Good Excellent
10 2 3 4 5 6 7 8 9 10
Dynamics
Tonal Balance
Phase Technology DARTS 525
Self-Amplified 5.1-Channel Speaker System
(compared with sub-$13k speaker/amplifier packages)
Imaging and Soundstaging
Transparency and Focus
Self-Amplified Main, Center, and Surround
Speakers
Poor Good Excellent
10 2 3 4 5 6 7 8 9 10
Value
216-1033
DCB-SURR surround speaker
System as a Whole
/