Outside
The SuperNova Millennium 15 is remarkably compact for a subwoofer with
two 15-inch drive elements. It’s a 17.5-inch cube, but the driver and passive
radiator protrude about 1.25 inches out from each side, for an overall width of 20 inches,
and the connectors add about half an inch to the front-to-back dimension. The enclosure is
made from 15 layers of laminated Scandinavian birch which is coated inside and out with a
thick, half poly-mix material that looks like a very course, black wrinkle finish. This
coating adds structural rigidity and damps cabinet panel resonance. The subwoofer looks
rugged and professional but it is not unattractive.
The black anodized connector panel on the rear of the enclosure doubles
as the chassis for the amplifier. There are four pairs of five-way binding post inputs and
outputs for speaker- level signals, RCA jacks for line-level inputs and outputs,
continuously variable controls for gain and low-pass frequency (50 Hz- 150 Hz), switches
for the phase (0°- 180°) and power off/auto-on, plus a remote control input. An IEC
power connector completes the rear panel. There is no heat sink other than the connector
panel itself.
The driver and passive radiator are identical in appearance. The frames
are about 16 inches in diameter, and the filled diaphragms are about 10.5 inches in
diameter, appearing flat from the outside. The active element faces left and the passive
faces right, with the connector panel at the back. No grilles are included, so the drive
elements are exposed.
A tiny infrared receptor for the remote control comes with a
substantial length of cable to allow it to be placed at the subwoofer or several feet
away. The hand-held remote control adjusts volume only.
Inside
The internal amplifier is a 580-watt class D pulse width modulation
(PWM) design. It features a toroidal transformer which is attached to the cabinet floor
and a patented optical distortion limiting (ODL) circuit to prevent the amplifier from
clipping regardless of input signal level or gain |
 setting. The gain control has a motor-driven pot for remote
adjustment of volume-level.
The low-pass filter is a fourth-order (24dB/octave) Linkwitz-Riley
configuration that is continuously variable from 50 Hz- 150 Hz. There is a first-order
(6dB/octave) high-pass filter on the line-level outputs fixed at 100 Hz. No speaker-level
high-pass filter is included.
The MAGMA 15 active drive unit has a 3-inch voice coil with a winding
height of 1.85 inches. The 7-inch diameter epoxy coated spider is spaced an inch away from
the top plate. The huge magnet assembly is an inch-and-a-half thick. The back plate is
bumped .375 inches, and the pole piece has a 1-inch vent hole through the center. This
cast-basket driver exhibits high construction quality and looks very rugged.
The patented SLAPS passive radiator has a flat diaphragm that is about
an inch thick, with a metal weight in the center. The push-pull surrounds are spaced about
an inch apart and are about 1.75 inches wide. The surround material is tapered in
thickness to allow 4-inch peak-to-peak travel with linear motion and no rocking. The SLAPS
has no basket or spider to inhibit travel.
Sound
The SuperNova Millennium 15 plays at incredibly high levels all the way
down to 18Hz and below. It delivered 118dB at 45Hz at the listening position which is
about 3 meters away from the subwoofer.. This level was maintained within 3dB all the way
down to 25Hz. I measured 117dB at 40Hz, 117dB at 35Hz, 116dB at 30Hz, 115dB at 25Hz, and
102dB at 20Hz with clear and solid sound. It produced a clean 98dB at 18Hz! Above 25Hz
these levels exceed those delivered by the huge Servo Drive subwoofer and they far surpass
any other reasonably-sized home theater subwoofer in the review. The Earthquake SuperNova
Millennium 15 produced the highest output of any practical
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home theater
subwoofer I’ve reviewed and it also performed well on musical selections.
The Earthquake subwoofer did an excellent job of reproducing the rhythm
and pace of music. Pitch definition was good. I managed to get a pretty good blend with
the main speakers. The Earthquake produced more powerful bass at lower frequencies than
other vented subwoofers and blended better with the main speakers. Sound effects are
another story.
Deep, high-impact bass for sound effects was simply outstanding. The
big Earthquake delivers the low frequency “air” of a large venue with
startlingly realistic punch when loud effects occur. You won’t find a subwoofer with
more slam than this one. It is the most powerful LFE subwoofer I’ve heard, period.
The ultra-high output level capability means that there will always be plenty of headroom
to reproduce the loudest effects with clarity and full dynamic range.
The patented optical distortion- limiting (ODL) circuit worked
flawlessly to prevent overloading the amplifier or driver. There was never a whimper of
distress regardless of signal frequency or level. At normal listening levels the SuperNova
just loafs along effortlessly, and when a really loud effect comes along this subwoofer
handles it without compression or distortion.
Conclusion
The Earthquake SuperNova Millennium 15 is the most powerful home
theatre subwoofer that I’ve heard and performs very well for music reproduction, too.
It beats the other vented designs for fidelity and delivers higher output than any other
compact home theatre subwoofer I’ve reviewed. It costs less than $2,000, looks good,
and is completely self-contained. Want to move your world? Get an Earthquake SuperNova
Millennium 15. Want to move your neighbor’s worlds as well? Get two.
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