Articles in Category: Home Audio News & Reviews

REVIEW: Earthquake Sound SuperNova MKIV-12P Subwoofer (OnHomeTheater.com)

I have a love/hate relationship with subwoofers. For years my preferred hi-fi setups were systems that absolutely did not reproduce deep bass -- such as my beloved Quad ESL-63s -- and I would dream of the day when I could add an accurate subwoofer and experience all of the music on my favorite records.

Nice thought.

Too bad there weren't any subwoofers at the time that were fast, transparent, and uncolored enough to match the Quads. That didn't stop bass junkies and subwoofer manufacturers from making some wild claims, however. After a while, I just gave up, convinced that getting the midrange right was a morally superior option to living with slow, colored, out-of-sync bass (yes, I was insufferable).

The thing is, subs got a lot better -- just like most loudspeakers. I began hearing subwoofers that were really musical and had phenomenally deep bass, such as Ken Kreisel's M&K MX-150 THX, and it was obvious that listeners no longer had to settle for boom boxes in the corners of their living rooms.

But old habits die hard, and I continued to begrudge subwoofers their floor space in my listening rooms. Of course, home theater changed all that. With really good HT systems, you've got to have a good subwoofer. Most of them, however, while better than the typical sub of yore, still leave a lot to be desired. In any case, most of the time, if you've got it set up correctly at least, you don't even notice a good subwoofer -- and when you do notice one of the truly great ones, you're likely to be struck speechless, which can be a problem for a reviewer.

Shortly after installing the Earthquake SuperNova MKIV subwoofer in my system, I decided to revisit the extended version of The Lord of the Rings: The Fellowship of the Ring. The minute the soundtrack announced the existence of Sauron, I was rendered completely inarticulate.

"****"

"????"

"!!!!"

And I meant it in the best way.

Loud organs, his glory forth tell in deep tone

There are beautifully finished subwoofers out there with rare wood veneers and discretely hidden connections and controls, but the Earthquake SN MKIV ain't one of them. It's a 15" cube clad in black polyurethane, sporting two 12" speaker cones (one is passive) with honking huge surround rolls, and a massive control plate (the amplifier's backside, really) sporting speaker connections, crossover controls, and line-level inputs and outputs. It's not ugly, just a tad brutal looking -- which I found refreshingly honest. It has the "I'll get the job done" integrity of an old Ford pickup truck.

Let's start with that amp panel. It has a full complement of controls and inputs. It has a pair of speaker-level inputs and satellite speaker outputs, line-level inputs (use these if at all possible), a line-level 100Hz high-pass output, volume control, 24dB/octave continuously variable low-pass filter (50Hz to 150Hz), two-position phase switch, signal-sensing on/off switch, a power-indicating LED, and an IEC power-cable socket. There's also an input for an infrared remote sensor that allows you to control the sub's volume via remote -- a nice feature, if a somewhat thumpy one.

The amp itself is a class D unit rated at 580W, and it incorporates a nifty Optical Distortion Limiting circuit, which controls and limits the input, preventing it from distorting or overloading the amplifier. Details are sketchy, but whatever it does, it does not prevent the SuperNova MKIV-12P from putting out prodigiously powerful bass. The digital amp runs cool, too.

The SuperNova MKIV-12P features two drivers, the primary one being an active 12" MAGMA driver, which sports a cast basket; double-stacked, high-gauss magnets; three-inch high-temperature-capable copper-wound voice coils; and that massive one-inch polyether-foam surround. The end result of all that technology is that the driver is capable of extreme excursions without distortion.

Mounted behind the active driver is a passive unit, a seemingly identical 12" driver lacking a drive unit. This driver has a steel weight attached that gives it a resonant frequency of 17Hz -- which makes it possible for the SuperNova MKIV-12P to reproduce bass about an octave deeper than any 15" cube with a 12" driver ought to be able to create. (Earthquake claims this design -- which it calls Symmetrically Loaded Audio Passive System, or SLAPS -- offers the slam and speed of a sealed-box enclosure combined with the efficiency of a reflex-cabinet design.)

Blake knew how deep is Hell, and Heaven how high

Actually, the real reason I seldom give subwoofers the credit they deserve is that, however good they are, you're going to spend a lot of time setting them up to sound right -- and even if I am an audiophile, listening to music and films is a lot more fun than futzing around with gear.

In this regard, the SuperNova MKIV-12P was no more difficult to set up than any other sub, but positioning it is definitely an exercise in trading off bass extension for speed. In my 13' by 25' by 10' room, I had no problems with extension, so I opted for speed and pulled the unit away from the room boundaries, but somewhat close to the wall behind my Stewart Filmscreen GrayHawk screen.

This position was not one that made manual adjustment simple, so I utilized the infrared sensor, which is convenient but not entirely free of problems. First, the sub produces an audible thump with each click of adjustment; there's also no easy way to determine the amount of adjustment you have dialed in (so maybe those thumps aren't a complete nuisance). As attractive as the remote option seemed in theory, I wound up setting the sub for "good enough" on both music and film and then leaving it be -- just like every other sub I've owned.

And darkness was upon the face of the deep

Except, the Earthquake isn't really like all the other subs I've owned -- it's better.

It goes deeper. Hard as it is to believe, I clocked it at over 100dB at 20Hz, which is freaking loud. Also deep. It is clear and, to my ears anyway, phenomenally accurate in its portrayal of special effects and music.

The underwater explosions in Crimson Tide weren't just loud, they were percussive. The sound smacked me in the chest, just as percussive blasts do in the open air. And those synthesized notes of doom and despair in LOTR: FOTR weren't just menacing, they played heck with my inner ear.

Lest you think I simply played the Earthquake too loud, I was careful to balance it to the sound of the Magnepan 3.6s that served as my RF and LF speakers. Most of the time, the sub wasn't audible at all, which is as it should be. But when there was deep bass, the MKIV-12P didn't mouth the words, it sang out with gusto.

When deep bass is properly reproduced, as it is with the MKIV-12P, it completely changes the way music's architecture is conveyed. Rautavaara's Eighth Symphony [Ondine 978] is a startlingly intense and massive work -- or perhaps I should say that it is a work of incandescent beauty, which achieves a sense of massive rightness in its sweep and in the massed brass choruses. It is emphatically not a heavy work, but it is a powerful one -- and the Maggies, coupled with the Earthquake, delivered it with weight and authority. No blurred lines, no weakened basses or lower brass; it was balanced and musical.

One deep calleth another

For the last year or so, Polk's $780 PSW-650 has been the subwoofer champion in my home theater. Its clean output, modest price, and ease of use have made it my current subwoofer favorite.

Good as it is, however, its two 10" speakers and 250W amp simply don't put it in the same league as the Earthquake SuperNova MKIV-12P. The 'Quake went deeper, dug in harder, and reproduced subterranean tones with far greater authority -- on the Rautivarra, on my beloved Little Feat's Waiting For Columbus [Rhino 78274], and on films like Apollo 13. Of course, you can buy two PSW-650s for the Earthquake's $1869 price tag, and two subs do load a room far better than one. On the other hand, the PSW-650 just won't put out 20Hz at all, no matter how many you pack in the room.

Not deep the Poet sees, but wide

No question about it, the Earthquake SuperNova MKIV-12P is the finest performing subwoofer I have yet auditioned. It plays louder and deeper -- and cleaner -- than anything else I have encountered. It certainly isn't the prettiest sub I've ever seen and it isn't inexpensive, but what is does is beautiful, and if you can afford it, I certainly recommend it.

I personally wasn't completely impressed by its remote-control capabilities, but your reaction to them might be different -- and a somewhat effective remote-control option is certainly superior to a non-existent one. This is a quibble, however, and the unit is far too good to be pecked to death by petty complaints such as this one.

The (ahem!) bottom line is that the Earthquake SuperNova MKIV-12P was so good it rendered me speechless -- and that's my final word on the subject.

...Wes Phillips
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Earthquake Sound SuperNova MKIV-12P Subwoofer
Price: $1869 USD.
Warranty: Two years parts and labor.

Earthquake Sound Co.
1215 O'Brien Drive
Menlo Park, CA 94025
Phone: (650) 327-3003
Fax: (650) 327-0179

E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Website: www.earthquakesound.com

REVIEW: Supernova MKIV w/Comparison Chart

Earthquake Sound makes a wide range of electronic components for the car audio, architectural audio and professional audio industries. They manufacture products on an OEM basis which are sold under other brand names and they make some of the world’s most powerful subwoofers.
    The Earthquake Sound SuperNova 12 inch MKII reached 113 dB at 35 Hz. This was the highest output level delivered by any subwoofer we had tested up until that time. When Earthquake set out to make an even more powerful unit, they wanted to produce a subwoofer with fewer sonic compromises – one that actually sounded better, not simply one that played louder. The SuperNova Millennium 15 accomplishes this goal by employing some interesting engineering innovations.
    Vented subwoofers, which include those using passive radiators, can usually play louder than sealed enclosure designs because of reduced cone excursion at or near the system tuning frequency. The downside is that vented designs can’t equal the transient response of sealed-enclosure subwoofers and typically have twice the phase shift and twice as much group delay. ( See the Sunfire Architectural True Subwoofer review for further details) Joseph Sahyoun, of Earthquake Sound, envisioned a vented subwoofer tuned to a subsonic frequency so that these phase and group delay problems could be shifted down in frequency into a range where they would be inaudible. He suspected that a vented subwoofer designed in this way could offer the high output capability of a typical vented system, along with the speed and linear-phase characteristics of a sealed system, within the audible range. Carrying out this concept proved to be harder than expected. A port would be too long to fit in a compact enclosure, and conventional passive radiators were not up to the task.
    Reaching a tuning frequency of 15 Hz or so, which is about an octave below the sealed system resonance, required the development of a new type of passive radiator. This patented design is called SLAPS, for Symmetrically Loaded Audio Passive System. The SLAPS passive radiator allows diaphragm excursion of up to 4-inches with symmetrical loading of the active driver on both inward and outward strokes. Now I will explain why it was necessary to invent SLAPS.

How low can you go?
    A subwoofer vent tuned to a very low frequency will be very large, just like an organ pipe designed to play a very low tone. The vent contains a volume of air that resonates at the chosen tuning frequency. The lower this frequency, the greater the volume of air required. As the  system is tuned to lower and lower frequencies, eventually a point will be reached where the vent will be too large to fit within the subwoofer enclosure.
    A passive radiator works just like a vent or port. The mass of the moving element ( passive diaphragm) replaces the mass of air in the vent. You can’t make the air in a vent heavier, but the diaphragm of a passive radiator can be weighted to tune it to a lower frequency . The vent (port) has to get longer and longer to lower the tuning frequency, but a passive radiator can stay the same size and just be made heavier. That’s not all there is to it, though.
    As the tuning frequency of a passive radiator gets lower, the required excursion ( or travel) of the diaphragm gets larger. Conventional passive radiators have frames or baskets, much like active drivers and the diaphragms are suspended at the outer circumference by the surround, with a pleated spider connected to the basket acting as a spring to center and return the diaphragm to its resting position. The spider limits the diaphragm excursion and can exhibit non-linear characteristics, providing unequal resistance to inward movement and to outward movement as excursion increases.

Slaps
    The SLAPS passive radiator has no spider or basket to limit diaphragm travel, and it uses a special double surround to provide perfectly symmetrical resistance to inward and outward movement. The surround has a half-roll shape facing outward like a conventional passive radiator, plus a half-roll facing inward towards the interior of the enclosure. These two push-pull surround sections are spaced about an inch apart and are made of material with a tapered cross section to provide perfectly symmetrical spring action to restore the diaphragm to its resting position with equal resistance to inward or outward movement over a very long range of travel. This surround design prevents any rocking motion, even when the diaphragm is weighted in the center, and eliminates the need for a spider and basket.
    The SLAPS passive radiator loads the MAGMA15 active driver symmetrically to help keep its long voice coil centered in the gap. This has the effect of extending the linear travel capability of the active driver, while permitting extremely long travel and high output from the passive diaphragm. The combination of the specially-designed Magma active driver and SLAPS passive radiator allows the system to be tuned to an infrasonic frequency, producing a phase response curve that looks like a sealed enclosure design, above 20Hz.
    The SuperNova Millennium should have the phase characteristics (above 20Hz) and ultra-deep bass extension of a sealed box subwoofer, along with the power and high output capability of a vented subwoofer. Let’s see how it actually performs.   

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 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.
 

Enclosure Type: Vented (passive radiator)
Driver (s): 1x15" active, 1x15" passive
Amplifier Power: 580 watts, Class D
High-pass Filter:
    Line-level 70Hz at 6dB/octave
    Speaker level: none
Low-Pass Filter: 24dB/octave variable
    from 40 Hz-120Hz
Dimensions (wxhxd in inches): 20x17.5x18
Weight (lbs.): 110

 dB measurements as tested by WideScreen Review, Buyer's Guide issue # 36 

 MANUFACTURER 

MODEL

MSRP$

DRIVER

dB@40Hz

dB@35Hz

dB@30Hz

db@25Hz

db@20Hz

dB@18Hz

EARTHQUAKE

SUPERNOVA

 3,000

15"

117 

117 

116 

115 

102 

98 

B & W

4000-ASW

3,000

15"

115

115

115

114

102

N/A 

BAG END

S-18E

2,680

18"

110

110

110

108

100

N/A 

TRIAD

PLATINUM

2,200

18"

N/A

N/A

N/A

106

92

90

VELODYNE

F-1800R

1,999

18"

112

112

113

110

98

N/A

ENERGY

ES-18XL

1,700

18"

114

114

112

106

98

90

PARADIGM

SERVO-15

1,500

15"

112

112

110

106

98

90

BAG END

INFRA-18

1,495

18"

108

108

106

102

90

N/A 

 

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