|
FPS
Model F1
Flat-Panel
Hybrid
Speaker
System |
| Sneak
Preview |
|
Clement
Perry
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15
May 2002 |
Last
month I had the
pleasure of being
given a sneak
preview of a
new-found speaker
system called the F1
from Flat Panel
Speaker Inc.
I received a call
from the one and
only Albert Von
Schweikert, Doctor
Emeritus of
Loudspeaker
Engineering, after
hearing rumors
swirling about of a
new
"killer"
system being
developed in
California based on
an innovative
Japanese flat panel
module. His
description of this
revolutionary
transducer made my
mouth water, forcing
me to jump on a
plane (which wasn't
easy for me after
9/11) to hear
first-hand. No one
has to ask me twice
to be the first
reviewer to get a
"sneak
preview" of
something new, so
off to San Diego I
flew. Of course, the
beautiful weather
and tropical
ambiance had nothing
to do with my
interest, of course.
I was also overdue
for a factory tour
of Von Schweikert
Audio, home of VSA
Consulting Engineers,
Robert Lee's
Acoustic Zen
Technologies, and
Silver Smith Audio
(Due to an
incredibly hectic
schedule I
unfortunately never
did visit Silver
Smith).
As
you may know, Von
Schweikert has been
a transducer
designer and system
engineer at many
speaker companies
over the years and
is currently the
Chief Engineer at
EgglestonWorks
Audio, among others,
as well as his own
company, Von
Schweikert Audio.
Mr. Von Schweikert
has won many
engineering awards,
including Product
of the Year (5
times) and Entrepreneur
of the Year,
awarded by the SBA
in 1996.
FPS
Flat Panel
Transducer
Japanese
reissues by
companies like
Impulse records,
Columbia and Blue
Note, to name but a
few, are regarded by
most audiophiles as
being the best in
their class. My own
personal visit to
Osaka in December of
2000 only confirmed
further why this is
so. Jazz, American
Jazz at that,
maintains a near
fever pitch level in
appreciation for
reasons that I am
unaware. The
Japanese show an
appreciation there
like we once did
here throughout the
1950's and early
60's. Ever dawn on
you why there
are such countless
valuable pressings
in both CD and vinyl
available in Japan?
Simple, supply and
demand. The
relentless quest for
quality and the
appreciation of
music and its
playback is
legendary in Japan.
So much in fact, I
find it not
surprising that a
new state-of-the-art
transducer would
come from Japan as
well.

FPS
of Japan has spent
years developing a
new type of flat
transducer that
greatly reduces the
disadvantages of
ordinary flat panel
drivers. Most
audiophiles have
heard the various
incarnations of
electrostatic and
planar magnetic
designs on the
market, and many
have had their love
affair with this
unique type of
device. However,
many grow tired of
the limited dynamic
range, lack of truly
deep and powerful
bass, and
locked-into-a-vice
type of imaging. The
lack of dynamic
range is due to the
limited excursion
potential of a
stretched piece of
plastic film in a
clamped frame; the
lack of deep bass
stems from
front-to-rear
cancellation caused
by the open baffle.
Many large panel
designs also beam
their high
frequencies like a
flashlight, so one
cannot move one's
head more than what
seems to be a few
micro-inches. In
addition, some
listeners complain
of electrostatic
"brightness"
or thin sound,
lacking in body. The
Acoustat panels were
also said to have
been highly colored,
hinting that
electrostatics and
planar-magnetic
speakers are not
"automatically"
superior just
because they have no
enclosure or
crossover. Indeed,
it seems that these
may be limitations
instead of benefits.
The brains at FPS
have actually found
a way to eliminate
their lack of
dynamics that have
haunted planar
drivers for ages.
Engineering
Aspects of the FPS
Transducer
To
eliminate the
dynamic range
constriction, FPS
utilized a rubber
half-roll surround,
just like cone type
drivers use. Indeed,
I have been told by
the engineers that
the excursion
potential of the FPS
units is
approximately 10
times greater than
most electrostatic
units, enabling
extremely high
dynamic range
potential. In
addition, to prevent
front-to-rear
cancellation of the
low range that
causes frequency and
phase response
aberrations, the FPS
drivers are loaded
into a narrow baffle
with a closed back
(the rear wave is
absorbed by a thick
pad of felt). Since
the size of the
individual FPS
transducers is quite
small, they do not
beam the high
frequencies. Indeed,
I found the
soundstage to be
extremely
"open"
when I walked around
the room. I was
literally amazed
when I heard a
direct comparison
against the new
Martin-Logan Aeon
electrostatic
speaker system,
which appeared to
image from inside a
closet due to its
very limited
dispersion pattern.
In great contrast, a
single F1 speaker
almost sounds like a
stereo pair, with no
muffling off-axis! I
remember having to
sit in a very small
sweet spot with my
Maggies, spending
many hundreds of
hours trying to find
a good place for
them in my room, to
no avail.
The
Sum of 72
The
most amazing thing
about the FPS
transducer is the
drive system. Each
3" × 4"
module that
Professor Von
Schweikert utilized
in the F1 system
employs twelve teeny
motors! These flat
diaphragms have 12
miniature copper
voice coils
imprinted upon the
surface, three
across and four
down. The voice
coils are spiral
shaped and are
connected to each
other by thin trace
of copper. A small
Neodymium magnet,
mounted on a
perforated metal
plate, drives each
voice coil. I was
amazed at how strong
the diaphragm was. I
could literally push
it a quarter of an
inch without
bottoming the unit
or stressing the
diaphragm! If you
have ever seen a
Magnaplanar or Quad
diaphragm, you know
that you can't push
on it, as it may
become damaged. The
clamped edge of a
common planar device
does not permit high
excursion, and
worse, the clamped
edge causes
reflections of
energy to
"stand"
upon the surface
when a signal is
being reproduced.
All said, each F1
speaker system has
72 motors! How's
that for
instantaneous
dynamic response, I
thought. No wonder
FPS calls their
flagship the F1:
does that stand for
Formula One racing?
Von
Schweikert Audio
Laboratory
Von
Schweikert Audio is
located just outside
of San Diego, in a
large industrial
park in El Cajon,
California. Von
Schweikert's sound
room proved to be
formidable: 25 ft.
wide by 75 ft. long,
allowing him to make
measurements almost
in free space. As
Von Schweikert
studied to be a
scientist, he has
all sorts of exotic
test equipment and
makes measurements
that I haven't even
heard of. In
addition, large
tuning panels that
are adjustable cover
his listening walls;
when the tuning
panels were in
place, the room was
somewhat dead and
probably very good
for making
measurements.
However, the
reverberation was
deep and immense
when the tuning
panels were moved
sideways, sounding
something like a
small concert hall
(great for
listening). The F1
was in the middle of
the room, next to a
Martin-Logan Aeon
system (one of M-L's
latest designs). Von
Schweikert's
impressive
collection of
electronics consists
of a Linn CD12
compact disc player,
a Hovland HP100 tube
preamp, and a
variety of
amplifiers,
including my beloved
Bel Canto EVo, an
8-watt Single Ended
Tube amp from
AudioNote and a very
impressive sounding
400-watt Spectron
digital amplifier.
Cables were by
Acoustic Zen, one of
my few personal
favorites, along
with some
experimental cables
by Paul Garner
called Verbatim.
(Stay tuned for a
review on these
interesting
spiral-wound copper
and silver hybrid
interconnects and
copper foil speaker
cables). When I
arrived at VSA, Von
Schweikert showed me
some of the FPS
diaphragms and
wanted to talk tech,
but when he saw my
eyes glaze over, he
led me to his
laboratory and sound
room upstairs. In
the middle of the
room stood the F1
prototype, a slender
speaker about 5 feet
tall but only
9" wide. The
graceful speaker has
a swept-back look
and is quite
interesting (see the
photos of the
engineering
"mule" in
their ad on our
front page). Von
Schweikert's
assistant engineer,
Kevin Malmgren, did
cosmetic design.
Transfixed
by F1 Transducers
There
are a total of
six-FPS (3 ×
4") transducers
in a vertical line
source, along with a
dome super tweeter.
In addition, there
are two 4"
midbass
"couplers"
that Von Schweikert
said were necessary
to blend the flat
panels with the dual
7" cone
subwoofers. Sitting
outboard and
attached by a long
umbilical cord was
one of the most
complicated
crossovers I have
ever seen. My fellow
reviewers know that
I am not
particularly fond of
excess, so the
amount of parts
boggled my
imagination.
However, Von
Schweikert pointed
out that there were
four circuits
covering four
different frequency
ranges; much of the
crossover is formed
by parallel shunts
to ground. In fact,
very few of the
parts were in series
with the drivers and
the parts quality
was excellent. After
hearing a
description of how
the circuits blend
the amplitude,
phase, and impedance
of the various
drivers (which is
done by sampling the
back EMF), I asked
about the bass
loading.
Acoustic-Turbo™
Bass System
It
seems that Doctor
Von Schweikert has
come up with another
variation of his
favorite bass
loading principle,
the transmission
line. As FPS calls
it the
"Acoustic-Turbo,"
I was dying to know
why. Well, it seems
that there are three
chambers of
different volumes,
with each chamber
expanding into
another, something
akin to horn loading
but not using
compression loading,
hence the name. The
first chamber is
small and expands
into the second
chamber where the
lower of the two
woofers is loaded.
Since the rear wave
output of the upper
woofer is fired into
the second chamber
(which loads another
woofer), there is a
velocity gain
created by the
expansion. When the
upper pair of
chambers are vented
into the third
chamber, there is
yet another acoustic
gain, further
amplified by the
Venturi port. Von
Schweikert says the
measurements
indicate that there
is approximately a
16 dB gain at 20 Hz
compared to a sealed
box. This design is
patent pending by
VSA and will be
licensed to FPS
exclusively.

How
Low Can You Go?
During
the demo, Kevin, the
mechanical engineer
at Von Schweikert
Audio, compared the
F1 to the
Martin-Logan Aeon
(which uses a metal
8" woofer in a
sealed air
suspension cabinet),
playing several
"mondo-bass"
cuts I have heard in
the past. In fact, I
highly value deep
bass thanks in part
to the pretty
incredible ROC 2002
subwoofer from Talon
audio. Well, simply
stated, the F1
simply destroyed the
Aeon (and most other
speakers I've heard
lately) in the deep
bass department. The
F1 bass was not only
deep and very
powerful, but was so
fast and clean that
it defies the
imagination.
Although the F1
sounds as tight as a
sealed box design,
the speed and
transient response
were far more
dynamic and also had
amazing clarity. I
could hear the
fingerprints on a
bass player's hand
as he plucked an
acoustic string bass
on the song
"Hush Now"
on Three Blind
Mice. Also,
there was a
tremendous
difference in the
dynamic range of the
F1 compared to the
Aeon, from bass to
treble. The
Martin-Logan sounded
very constricted,
shallow and
compressed, while
the F1 sounded like
it was connected to
some sort of gimmick
device like a
dynamic range
expander! Von
Schweikert feels
that dynamic range
is one of the most
overlooked
specifications to be
addressed in modern
speaker design. Von
Schweikert uses
blind ABX testing,
so that when he and
his listening panel
audition a new
design, no one knows
which speaker is
playing. In this
case, there was no
question of which
speaker was the most
realistic, since the
efficiency and
dynamic range of the
F1 was absolutely
incredible.
Comparably priced,
this, in my opinion,
did not spell good
news for
Martin-Logan.
Midbass
Couplers
When
first approached by
FPS engineers to
design their
loudspeaker, Von
Schweikert told me
he was not certain
that he would be
able to blend the
incredibly fast and
transparent planar
drivers to a cone
subwoofer system
with 100% success.
However, using the
twin 4"
couplers did the
trick. He explained,
"The
deep bass
integrates
completely with
the
hyper-transparent
flat panel
midrange units.
The transient
response of the
two 7"
woofers is not as
fast as a
half-dozen FPS
transducers, as
the directional
patterns of the
two driver types
are not similar.
The large woofers
behave as a point
source, with bass
pressure wrapping
around the speaker
while the line
source of flat
panel transducers
radiate a
vertically
oriented beam
wave. The
differing
radiation patterns
result in dips in
the 90 degree
off-axis
horizontal
frequency and
phase responses,
so the 4"
midbass couplers
allow a transfer
of the radiation
pattern and the
frequency response
laying between the
deep bass and the
midrange."
Rarely
have I heard vocals
as natural and clean
as the many driver
F1, with nary a hint
of coloration.
Although
the FPS panels go to
20 kHz, Von
Schweikert says
"they are
somewhat inefficient
at that range."
Therefore, Professor
Von Schweikert
utilized a 1"
silk fabric dome
super-tweeter to
enable the F1 to
reproduce 25 kHz
"air" and
sheen from violins
(his favorite
instrument) as well
as cymbals, bells,
and chimes. When
comparing the high
frequencies of the
F1 to the
Martin-Logan, I was
amazed how much
"there"
and "air"
the F1 possessed,
allowing cymbal
harmonics to rise
vertically! On
violin solos, the F1
had more bloom and
fullness compared to
the electrostatic.
In fact, on some
recordings, the M-L
sounded somewhat
thin and bright,
while the F1 sounded
full, rich, and
highly musical.
Comparing
the midrange,
especially with the
human voice,
completely sold me
on the F1's flat
panel transducers.
Although the
Martin-Logan is no
slouch on voices,
the electrostatic
tends to favor high
frequencies,
especially their
harmonics. The M-L
was often
overbearing in the
upper midrange, even
with Von
Schweikert's highly
musical playback
gear, while the F1
sounded much more
full-bodied and
rich; so much so,
that I was musically
seduced. However,
the F1 was not
overly warm or
thick, which is a
big faux pas found
in many speakers.
Art?
Science? Or Sci-fi!
All
in all, the F1
appeared to have
many strengths and a
high degree of what
I can only call
"magic"
due to its seamless
driver integration,
wide and open
dispersion, and
incredible bass
punch. No matter
where I stood in the
room, the F1 sounded
fantastically
"real" as
well as highly
enjoyable. Was the
F1 a scientific
breakthrough, as I
would believe from
seeing the FPS
transducers, or was
it art and/or magic?
Since
this is a sneak
preview and not a
full review, I won't
go any further
except to say that
the F1 is far
superior to the
Maggies I owned a
few years ago. As
well, the F1
"blew
away" the
Martin-Logan Aeon so
badly that I suspect
the F1 will be soon
rated in the
"Super
Speaker"
territory. Of
course, only time
will tell…..
Lastly,
I am quite skeptical
of the many driver
and complicated
crossover
loudspeaker since
being swooned by the
Talon Khorus
no-nonsense minimal
approach. That duly
noted, there is
something very
special in this F1
design that is purer
in heart regardless
of complexity. Most
rewarding is its
target price. I'm
told the F1
loudspeaker is going
to be priced for the
real "Joe"
Audiophile at around
$7,000. Can you
imagine, a
loudspeaker that
rivals the huge
$70,000 Pipe Dreams
in
multiple-driver-count-per-enclosure,
uses a new driver
technology that is
simply breakthrough,
only stands 47"
tall, yet costs less
than seven grand?
See FPS in Room 625
at Stereophiles'
Home Entertainment
Show at the NYC
Hilton Hotel May 30
through June 2. I
will be there.
Hey,
Christmas may be
coming very early
this year.

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