- Frequency Response: 20 Hz – 27 kHz
- Impedance: 8 ohms nominal
- Sensitivity: 94 db @ 1m – 1 watt
- Power Requirements: 3 watts – 500 watts
- Dimensions: 55” H x 9” W x 24” D Weight: 190 lbs ea.
- Driver Compliment: Per Speaker 1 - Accuton 1.2” Ceramic Tweeter
1 - Accuton 6.5” Ceramic Midrange 2 - 12" Nomex Fiber Cone Heavy Duty Woofers
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The desire to create a breakthrough in any field of human endeavor must be
fueled by a burning passion to be the best. Coupled with this must include the
requisite expertise and the experience necessary to actually accomplish this
daunting task. Further add the endless hours of time and labor with the need for
boundless energy and the prospect of succeeding may nevertheless still prove
illusive. However, when all of the above ingredients coalesce and the goal is
attained, the result is the Coincident Speaker Technology Pure Reference
Loudspeaker.
The Pure Reference is the culmination of a lifetime’s devotion and fanaticism
with recreating the live musical experience in the home. This speaker exists for
only one purpose: to enhance the conveyance of the musical message to a degree
not experienced outside of a live concert. No expense and no effort were spared
and no detail was deemed too trivial in creating the Pure Reference. The mission
in bringing the Pure Reference to fruition was to afford the music lover the
opportunity to experience in his own environment the most accurate musical
reproduction possible with virtually any amplifier in existence, from flea
powered SETs to large solid state and everything in between.
The Pure References can be easily driven to concert hall levels by low powered
tube amplifiers (3 watts or more) because they possess the 5 requirements which
make this possible:
1. High sensitivity (94 db @1m-1 w)
2. Uniform high impedance modulus (flat 8 ohms)
3. Total absence of any hard phase angles (meaning they are absolutely phase
coherent electrically)
4. Very tight bass tuning (which makes it easier for low damping factor- high
output impedance amplifiers like SETs to control the woofers).
5. Simple first order crossovers which do not rob amplifier power or reduce
speaker sensitivity.
Many audiophiles believe the most accurate amplifiers are single ended triode
tube designs, yet few speakers are capable of being properly driven by these
amps. This creates a paradox of sorts. Speakers need amplifiers to create sound,
yet the finest amplifiers cannot be used by virtually all the state of the art
speaker contenders. These speakers must then be mated to inferior sounding
amplifiers with resultant compromised sound. The Coincident solution is to
create the finest loudspeaker that can be optimally driven by the finest
amplifiers. The end result is the most accurate musical reproduction possible.
To create a state of the art loudspeaker requires that every component used in
the design is the finest and that the sum of its parts are synergistically
matched so that the final product is a unified whole. Therefore, not only must
the design and concept of the speaker be state of the art, so too must the
execution. This means that all the ingredients which comprise a speaker must be
given equal attention with none being deemed less significant. Everything
ultimately affects the sound, no matter how seemingly trivial it may appear to
be. Everything used in the Pure Reference was thought out in excruciating
detail, tested and verified. From the less observable parts such as mounting
bolts, wiring length, and solder to the more obvious such as crossover
components, drivers and enclosure materials, nothing was left to chance. The
Pure Reference is state of the art in every conceivable manner.
Drivers – 1. Not only because they represent the finest currently available, but
because they conform optimally to the intended design. 2. Are very robust and
reliable. They can handle tremendous amounts of power with no sense of strain or
fear of break down. Yet at the same they are highly sensitive and require very
little power to achieve high sound pressure levels. 3. Have very wide bandwith
and smooth roll off characteristics outside of their respective optimum
frequency range. 4. Possess very uniform impedance modulus. All of the above
listed factors mean that the crossovers used in the Pure Reference can be
exceptionally simple with only one component in the signal path for each
frequency section. Impedance correction components are not even required, so
smooth is the impedance curves. All this translates to unrivalled purity and
transparency. The uniquely special qualities of the tweeter and particularly the
midrange driver, allowed for the first time, a state of the art, full range
speaker using only 2 drivers to cover the frequency range from 100hz – 27khz
with the midrange unit alone reproducing all the midrange frequencies. This
meant no crossovers or differing drive units with their own individual sonic
signatures involved in reproducing the highly crucial midrange. All the mid
frequencies now speak with one voice. This sense of cohesion is immediately
apparent in contrast to other competing speakers. Not only do all instruments
not change character as the frequency range is traversed, the precise
localization of instruments in space takes on a palpable realism that is spooky.
Tweeter – In order to reproduce all the upper frequencies with complete
transparency, transient speed and precision and simultaneously be capable of
capturing all the attendant harmonics necessitated the employment of a tweeter
with ultra low mass, extremely high cone rigidity and hardness. The driver that
perfectly fits this bill is the Accuton ceramic tweeter. The stiffness/weight
ratio of this tweeter is unsurpassed with the only exception being that
company’s diamond diaphragm unit. There is no sound that can elude its very
nimble grasp yet its inherent strength permits its response to well beyond the
limits of human hearing. Furthermore, this special tweeter presents a purely
resistive, totally flat 8 ohm load with no dips, no peaks or spikes. Very high
sensitivity is partly due to the use of a powerful neodymium magnet structure. A
very solid, and acoustically inert faceplate ensures resonant free reproduction
and the elimination of diffraction affects. This tweeter has proven to be nearly
indestructible. It can be driven to high SPLs with distortion artifacts that are
vanishingly low. Furthermore, at low or high levels, there is no change in sonic
characteristics. The tweeter always sounds detailed, smooth and refined.
Midrange – The all important midrange is where the majority of the music
emanates. No speaker that aspires to state of the art status can be compromised
in this vital area of performance. To that end, what many would consider the
purest driver available for this task was chosen for the Pure Reference. The
Accuton 6.5” ceramic midrange proved to be the perfect choice on many levels.
Firstly, it happens to be the highest resolution, lowest coloration driver
capable of flat response from 100hz – 4khz. Secondly, since it is constructed
using the same cone material as the tweeter, no other driver could be as
cohesive and seamless. The combination of the tweeter and its companion midrange
sound like one driver operating from 100 hz – 25khz. The midrange unit features
an oversize neodymium magnet for very high sensitivity, a titanium voice coil
former and a double roll surround for complete linear motion. Terminals are
thick gauge, gold plated copper which ensures large contact area and a very
solid connection. While this driver has very flat, even response from 70 Hz –
6000 Hz, it is operated in the Pure Reference only from 110hz to 4 KHz.
Therefore, the midrange driver reproduces all the midrange frequencies (where
the ear is most sensitive to crossover and phase anomalies). Couple this to a
tweeter that has virtually the identical sonic characteristics and the end
result is the coherency of a single driver, crossoverless speaker. The midrange
driver is rolled off at the low end acoustically by the use of bass tuning, (
the purest way to accomplish this) not electrically which would require the
addition of another component(a large value capacitor) in the signal path This
limited operating range ensures completely optimized response, highest
sensitivity and power handling capability and lowest distortion. Preventing the
driver from reproducing the bottom octaves relieves the midrange units from
unnecessary long cone excursions which increases upper frequency distortion. The
remarkable ceramic midrange’s wide frequency response, high power handling
capability, high sensitivity and state of the art sonics all combine to allow
for the first time, the use of a single driver to reproduce all the midrange
frequencies in a reference loudspeaker. In the past, due to the inherent
limitations of conventional midrange transducers, multiple drivers were required
and they still had to be limited in response since they could not adequately
cover the range of frequencies from 100hz- 4khz. Coincident is a firm believer
that simple is always better when it is possible. The Accuton high sensitivity
version ceramic midrange, not only made it possible but does it better as well.
Woofer - For state of the art reproduction, subwoofer bass that is seamless with
the mids and the highs is mandatory. Not only must the bass extend flat to 20
Hz, with weight, authority and impact, the low frequencies must be articulate,
tightly tuned and never sound boomy, or out of balance with the rest of the
frequency spectrum. It is in the midbass and low bass where most speakers suffer
badly with comparison to live music. When attending a concert the visceral
impact of bass and midbass instruments (such as drums, double bass etc.) is awe
inspiring. The sense of weight and intensity can be heard as well as felt. This
rarely if ever happens when listening to music at home on an audio system. It is
in this area of performance, possibly more than any other, that home speakers
fail to measure up. The speakers that are relatively adept in this area are
mostly hopelessly inadequate everywhere else. Conversely, the speakers that are
transparent and truthful in the midrange and the highs most often do not at all
recreate the sense of drama and intensity in the low frequencies. Are these two
areas of performance mutually exclusive? For the overwhelming majority of
speakers, the answer is yes. There exist very few speakers that are smaller than
a mini van and cost less than a bungalow that can do it all. Until now, that is.
The Pure Reference is unique among speakers of reasonable size and cost, that
can with equal aplomb capture the sound of a pin dropping and realistically
recreate the furor of a cannon being shot. How is this accomplished? It starts
with an enclosure of the proper volume (the laws of physics must be adhered to)
and total rigidity and ends with the selection of the finest woofers that money
can buy that are specifically designed for this purpose. The new 12” extra long
stroke unit employed in the Pure Reference has pushed the performance limits for
subwoofers. The construction standards are truly remarkable: Thick cast iron
frame ensures complete rigidity, heavy duty, stiff, Nomex fiber cone that is
almost impervious to flexing, a magnet structure that weighs in excess of 15
lbs., thick gauge gold plated copper terminals to maintain high current
capability. This driver fulfills every demand for deep bass (f3 is 17 Hz). With
its unlimited power handling capacity, 110 db levels at 20 Hz with virtually
immeasurable distortion and complete long term reliability, this new design
accomplishes state of the art bass reproduction that was previously not
possible. While a single driver will excite and please the most demanding bass
aficionado, imagine what two of these per speaker will accomplish. The Pure
Reference uses a pair of these remarkable subwoofers in each speaker. For the
first time, live music impact, punch, and genuine subwoofer bass with all the
visceral excitement experienced when attending a concert is a reality. Because
the tuning of the woofers is extremely tight, there is no concern about
overloading a moderate size room with excessive bass. The bottom octaves, for
all their explosive dynamic capability, are perfectly in balance with the
midrange and the highs. There is no accentuation of any frequency range. The
Pure Reference is beautifully balanced from top to bottom. Indeed, the speaker
not only measures virtually flat from 20Hz – 20 khz, it sounds that way as well.
Enclosure – The Pure Reference, out of necessity, is a large, albeit elegant
speaker. It is the size it is, not because it looks impressive (although it
does) or as a justification for its selling price, (which is a genuine bargain
although it is hardly inexpensive), but because to fulfill its mandate as a
truly full range (20 Hz – 20Khz) state of the art transducer, it had to be. This
is a simple case of adhering to the laws of physics. In order to achieve true,
undistorted 20 Hz bass response, the cabinet volume must be a predetermined size
(and that means big). Constructing a speaker of proportion this generous and
have it be as non resonant and inert as a small speaker, proved to be a
monumental task. The challenge commences with the selection of the base
material- 1.15” MDF Hardwood which is veneered in furniture grade Ash inside and
out. The tweeter and the midranges are housed in their own ported sub enclosure
which contains computer designed window braces horizontally placed between each
driver. The woofers are mirror imaged side mounted on a double MDF wall (2.3”
thick) so that their massive cone excursion capability would have a totally
rigid foundation impervious to any flexing. Computer designed window braces are
horizontally located between and vertically placed beside each woofer to further
augment the integrity of the enclosure. In fact, computer designed window braces
are placed every 6” within the enclosure to ensure that the cabinet is
absolutely rigid. As with all Coincident speaker enclosures, the fundamental
resonance frequency is benignly high (350 Hz). All this effort, technology and
innovative design and meticulous execution results in an enclosure that does not
contribute its own sonic signature to the sound. To ensure a solid foundation
for the speaker, Coincident Extender Feet (which enlarges the footprint by 4”)
and oversize dual tapered solid brass spikes are included.
Crossover – As with all Coincident speakers, first order crossovers (which are
the purest and preserve phase coherency) are used with only the finest
components, matched to within 1%, all hardwired with lead to lead construction
(eschewing the use of unnecessary wires or connectors). The signal path contains
only one capacitor (Mundorf – The most transparent cap for the purpose) and two
inductors (proprietary 10 AWG OFC Litz - one for the midrange and one for the
bass). That is it. Elegant simplicity but as Einstein remarked- not too simple.
This crossover is the most transparent, unobtrusive in existence. In bypass
tests, its presence is virtually undetectable.
The Pure Reference offers:
Full range, breakthrough state of the art sound; Stunning aesthetics; The
ability to be driven by any amplification including SET tube amps; Easy
placement in rooms ranging from moderate to large with placement to within 20”
from the back wall if so desired; State of the art design and construction with
lifetime reliability. |
