Downward
firing 10.5" long throw rigid aluminium driver.
120w
True RMS amp panel with digital display.
XLR &
RCA low level connectors.
High &
Low level simultaneous connection capable.
Infinitely
variable frequency contour.
Produces
a superb low 10Hz.
Box in
box rigid, ported cabinet.
Introducing
the breathtaking Reference I active subwoofer
from MJ Acoustics. Capable of producing a super
low 10Hz using our latest D.A.M.P
technology with a digital
display - taking the guess work out of setting
up your subwoofer.
Amplifier
Resulting from an extensive development program, the
120Wrms DC-coupled BI-Polar amplifier provides the
engine to power the perfectly matched 10.5" ultra
long throw aluminium woofer. The power supply has
been designed to awesome requirements. We fit a 150va
Double Insulated Toroidal transformer which has been
designed specifically for this audio application.
The rectifier used is a 10 Amp 60v bridge version;
it, of course, never sees 10 amps or 60 volts as this
would equate to 600W's but it is just an example of
how over engineered this amplifier is, and substantiates
why, when deep transients are required, the amplifier
has enormous reserves of power to accommodate with
utter ease even the deepest of explosions. To aid
this the capacitors used are the large bucket type
with a ripple current of 10 Amps each and selected
because of their high temperature and minimal loss
characteristics. The transistors used are the Metal
Oxide Semiconductor Bi-Polar type and specifically
designed for audio applications.
Crossover
The "Reference I" has the ultimate in
sophisticated crossover circuits. A Digitally Accurate
MicroProcessor controlled crossover circuit (DAMP),
incorporates a digital display so that the upper
response limit can be set in musically accurate
variable increments between 30hz and 120hz. A "straight-through"
LFE bypass facility is activated at one end of the
controls travel which allows the input signal to
bypass the filter circuit. The LFE bypass is used
where an already filtered signal is offered to the
low level input sockets. An example of this would
be a sub output from a dedicated control pre-amplifier
such as found in a Home Cinema system.
There are separate gain controls
for high and low level inputs, a "straight-through"
LFE bypass and an audibly transparent, "Automatic
Speaker Protection" (A.S.P.) circuit which
monitors the output stages for clipping and limits
the cone movement if the amplifier is being over-driven.
Professional Neutrik Speakon connectors are standard
for the "Reference I's" stereo high level
input. Gold-plated pins inside and an approved touch
proof design to cater for potentially high voltages
that can be connected to it complete the high level
input socketry. The "Reference I" also
offers a balanced low-level XLR input and output
for use with professional mixing desks and suitably
equipped domestic systems. Additionally, gold plated
RCA connectors are offered to cater for input and
output. There is a relay in the signal output of
the amplifier which waits for 2-3 seconds before
it connects the loudspeaker. This allows the power
supply to settle and prevents a loud thump that
would occur without it. When switched off, the relay
instantly disconnects the loudspeaker and allows
the power supply and output transistors to discharge
without noise. The amplifier panel is constructed
from high grade 4mm thick aluminium sheet and has
a 0.46ºC/W Heat-sink rating. Additionally the
Bi-Polar transistors are bolted to this plate to
further reduce the required heat build-up as output
rises. This combination enables the amplifier, even
under continuous high loads to run amazingly cool
during operation. As an added security measure a
90ºC thermal trip is added to the platform
to prevent heat stress to components when over driven.
Speaker
Using a die-cast solid aluminium chassis of monstrous
proportions creates the rigidity that is so important
in sub-bass speaker requirements. Any distortion
of the chassis under extreme load will detract from
the goal of pure sound wave formation. As we all
know the creation of sound waves comes directly
from the movement of the cone surface through the
air. The longer the movement of the cone, termed
as its excursion, the more air it moves and up goes
the sound pressure level. We like to think of our
10" driver as the best of all worlds. It has
agility, rigidity and declarative damping to enable
the cone to move with lightning speed back and forth
through the air. Incorporating an optimized linear
motor with progressive suspension to avoid bottoming
and allow maximum linear excursion. The result is
extremely low total harmonic distortion (THD). The
voice coil is aluminium and bonded to the aluminium
cone to form a one piece structure which is much
stiffer than could be achieved from a paper version.
The result is a piston like action adding to the
accuracy of the wave formation. Better heat dissipation
and further reduced THD is achieved as a result
of the rigid one piece aluminium cone structure.
The massive rubber cone surround together with the
semi-rigid lower damping apron serve to bring the
cone to an almost instantaneous return to its resting
place between transients. Truly, the muscle of the
system and the working end of this bass producer.
D.A.M.P.
D.A.M.P. (Digitally Accurate MicroProcessor)
This Digitally Accurate Microprocessor controlled
crossover circuit (DAMP)
The "Reference I" has the ultimate in
sophisticated crossover circuits. A Digitally Accurate
Microprocessor controlled crossover circuit (DAMP),
incorporates a digital display so that the upper
response limit can be set in musically accurate
variable increments between 30hz and 120hz. A "straight-through"
LFE bypass facility is activated at one end of the
controls travel which allows the input signal to
bypass the filter circuit.
A.S.P.
A.S.P. (Automatic Speaker Protection)
This circuit monitors the output and the input of
the amplifier. As the output reaches close to the
limit of the power supply rails the input is instantly
reduced to prevent the amplifier from clipping.
The dynamic range of the amplifier is not compromised
as the circuit has been set to activate at a point
beyond the full dynamic range before protection
is activated
