Sunfire True Subwoofer Signature

You too, can have your very own LFE Rocket Launcher

Francis Vale

Some things don't make any sense, like Clinton dropping his draws in the oval office with Paula Jones' lawyers looking on. Or why adding a great subwoofer to a full range speaker system should make everything sound not just a little better, but a whole lot better. These are both deep mysteries, perhaps best left for generations to follow to answer. But what the hell, even if we can't decipher why Bill's brains so often live below his belt, I can at least tell you about something else that will shake your lower extremities -- and the furniture, the room, the building, and maybe even the concrete sidewalk outside the house. It's the Sunfire True Subwoofer, Signature edition. The "Signature" here belongs to none other than that wattmeister supremo, Bob Carver.

His Signature sub is a diminutive semi-flat black box, 13 inches to a side and 15 inches wide, but weighing in at an Oye-I-gotta-call-the-chiropracter 53 pounds. Mucho mass + small size = what the hell is going on here? The innards of this neutron star of subwoofers tell the tale. The driver's magnet measures 7.5 inches in diameter, and weighs over 14 pounds. That's about an order of magnitude heavier than magnets used in a three hundred pound Godzilla speaker system. The voice coil itself measures a whopping three and one-quarter inches in diameter. And get this: it has a maximum excursion of two and one third inches! If subs live in a secret world of size does count then most of them are in deep therapy over the True Subwoofer. Their comparison anxiety will only get worse when they find out the Sunfire Signature comes equipped with a Mama Mia! 2,700 watt amplifier. Anything less powerful would just go limp at the sight of such a massive driver assemblage.

However, the sub's huge back electromagnetic force takes a heavy toll on those 2,700 watts. The actual power delivered to the load is about one-tenth that amount. But hey, the thermonuclear back-kick produced by this huge driver and its magnet would dim even ConEd's power grid. At full output, about 75 pounds of force are trying to claw their way of out of this sub's restrictively small enclosure. Of course, because the Sunfire True Subwoofer is built like the proverbial brick outhouse, escape is not an option. However, when they are pounding away in a full shake-the-foundation tantrum, these enormous forces can get the True Subwoofer's half a hundred pounds doing a mad tarantella across your floor. This thing is the Arnold Schwarzanegger of subs.

So where do you put this fierce little mutha? Carver recommends a kitty corner placement, with the active and passive speakers each facing a wall at the same angle. What's that? There is actually something passive about this hoo-hah! kickin' thing? In truth, this passive, but oh so very aggressive, speaker is but one of the many engineering reasons why the Signature sub can go down to a true 16 Hz, and easily crank out SPL's of well over 110 dB in your listening room. Energy from the active driver actuates the passive unit, thereby augmenting overall bass response.

The active speaker says basta bass at about 33 Hz, and there's not much air it can still push into the room at 16 Hz. However, its passive counterpart has a resonant frequency of about 16 Hz. So even after the active unit says sayonara, the passive radiator just keep on producing significantly useful output way down low. Amazingly, the overall diameter of each speaker is only about ten inches, and its actual working surface is about two inches less than that. Each of the speakers also has an unusual, very stiff rubber surface.

This is all very clever stuff. And it's also very tough. Carver takes great delight in doing a Mohammed Ali punch out its lights number on the passive speaker to demonstrate its near indestructibility.

Once you have schlepped this black back breaker into a corner, you hook the Sunfire True Subwoofer up to your system via its RCA line level inputs or the banana jacks for speaker-level input. We used the line level inputs, and ran Nordost Red Dawn interconnects off the oh-so-very-fine Theta Casablanca surround processor's primary LFE (Low Frequency Effect) sub jack. The LFE subwoofer channel is a dedicated channel used for routing Dolby AC-3/DTS whackem-sockem sonics up to 120 Hz. The LFE channel carries high level bass and augments the normal bass of the other five surround channels. The LFE is used mostly for special effects, like explosions or a run amuck T-Rex. The Casablanca can support up to four (!) foundation-cracking subs and it also has an extensive bass management system. In our case, the LFE output to the Sunfire was configured using the Casablanca's "full range" sub setting, with no specified slope or crossover point.

After it was jacked into our system, we were faced with several decisions about how to fine-tune the Sunfire Signature sub for maximum performance. A metal plate on one of the True Subwoofer's sides features an array of switchgear and dials, all for your tweaking pleasure. The first items you notice are three small rubbery feeling dials. The middle knob sets the crossover frequency, and offers settings from 30 Hz to 100 Hz. We used the sub's apparently factory suggested setting of "Normal/65 Hz", which is the only one marked between the two frequency extremes. As the other intermediate crossover settings are unmarked, guesstimate trial and error is the order of the day, depending upon the type and capabilities of your speakers.

The True Subwoofer's crossover slope changes automatically based on your desired setting. The Sunfire slope descends from 36 dB per octave at 100 Hz, to progressively shallower slopes the lower you go -- about 22 dB at 40 Hz. This was another reason for our using the full range setting on the Casablanca. The bass management software inside our Casablanca review unit did not have Theta's planned revisions that will allow you to independently adjust both the high and low pass filter slopes. Moreover, the True Subwoofer does not allow you to switch out its crossover completely, as some other subs do. So, to avoid the effects of cascading filters, one of these two units' crossovers had to give. In this case, it was the Casablanca's.

Like most other subs, the Sunfire also offers a phase control. However, unlike the usual two position, zero phase shift/180-degree inversion switch sported by competing subs, the True Subwoofer's rotary dial lets you gradually tune for the optimal phase shift setting in your room. Finally, the Sunfire has a simple toggle switch marked "flat" and "video contour." The flat position kicks out the bass jams down to 16 Hz. But the video contour position starts the True Subwoofer's frequency response rolling off at 30 Hz. Because the corner position favored by most sub vendors tremendously augments bass output and will typically produce a significant low frequency response rise, we played with both settings. We found that the True Subwoofer played flatter overall with the switch set at video contour. However, bear in mind this setting only applies to our corner placement for movie material, as we shall see later on.

So now at last we get to this thing's really bad ass control. The top knob on the True Subwoofer panel is for setting output level, and offers range settings of "minimum" (at 4 o'clock) to +15 dB (all the way round clockwise to approximately 2 o'clock.). The volume settings are laughably vague, but a word of advice: If your wife values the china, do not, repeat do not, turn that sucker up beyond the 6 o'clock position when you first turn on the True Subwoofer Signature. -- Unless you really enjoy causing trouble in the `hood; or having the dear girl ruthlessly beating you over the head. If so, simply set the level at 12 o'clock, plug in the sub, get a pissed off T-Rex stomping across your video screen, and then merrily wait for the neighbors, police, and FEMA to start running around your neighborhood looking for the earthquake's epicenter. And be sure to duck the broken china as it hurtles by.

Your only homeowner's insurance hope is that everything in your listening room is solidly nailed down when things get scarily pyrotechnic. The Sunfire True Subwoofer Signature sub can crank huge SPLs. More important, it doesn't just make some big flaccid fart when it goes loud. That T-Rex's thud! Thud! Thud! as it sashays across your screen has accurate definition and 3-D solidity.

Your guts also shake loose even when there is no discernible LFE signal. Depending on the movie's sound effects, you often feel this vague, uneasy quivering in your body. This deliberate, deep sonic anxiety adds a huge dramatic impact to the movie watching experience. Those Hollywood people know their audio effects stuff, and the Sunfire True Subwoofer let's them strut it in low style.

Bottom line, this Sunfire sub should come with a warning label, "Hazardous to your lease." We have never experienced surround sound bass like that produced by the Sunfire True Subwoofer Signature. And it doesn't matter if the source is Dolby Pro, Dolby Digital, or DTS. If you want the very best in home theater, then this incredible product is a must have.

But the real shocker came when we tried using the Sunfire True Subwoofer as part of our stereo system for just listening to music. Anyone who has ever tried it knows it's incredibly difficult to get a subwoofer properly integrated into a high-end stereo rig. But once set-up right, the results can be terrific. For example, we had great success with the Hsu subwoofer and our previous Apogee Caliper Signature ribbon speakers. (One more "Signature" around here and we can personally initiate a California Referendum.) The Calipers were wonderful speakers, but below 80 cycles or so, their bass panels harmlessly broke wind. The Hsu changed all that, and in combination with the Apogees, this combination would rock downtown.

Then we got a pair of the remarkable, don't-you-wish-you-had-a-pair, full range Analysis Omega ribbon panels made in Greece. So far as they know, Gordana and Francis are the only people in the U.S. who have the pleasure of this incredible speaker's company. The Omegas are spec'd down to 20 Hz, but as a practical matter, they run out of gas at about 38 Hz. However, even at 20 Hz, their 6 foot high bass ribbon panels don't flap in the musical breeze, thanks in large part to the iron fisted grip of another stunning Bob Carver design, his Sunfire Signature amplifiers (when Bob signs off on something, he's true to his word).

We tried using the Hsu sub with the Omegas, but unlike the Caliper combo, the sonic results were decidedly mixed, even after much fiddling with cross over settings, sub placement, etc. And so, both the Hsu and the Calipers were ultimately put in our second, smaller listening room. As it also happens, the Casablanca is that rare breed of surround processor which actually rivals purist high-end preamps when playing in its "analog direct" stereo mode. Thus it was that Francis and Gordana lived for many happy stereo sub-less months using just the Casablanca and the Analysis Omegas. Until the Sunfire True Subwoofer arrived.

We interrupt this Sunfire True Subwoofer Signature review for some words about the Sunfire Signature amplifiers: These cool running, modestly sized, easily hefted amps put out 600 watts per channel into 8 ohms, and 1200 watts per channel into four ohms. You read those staggering numbers right. And also read this right: these incredible amplifiers only cost $3,000. Before you buy a multi-kilobuck, space heater Krell or Levinson, you must audition this astonishingly good amp first -- especially if you have a tough speaker load to drive. This was proven in spades when we hooked up the Sunfire Signature amps to the 81-dB sensitive MBL 101Ds a couple of reviews ago. What was a pretty good speaker became simply outstanding with Bob's black beauties in the amplifier chain.

In contrast, the Omegas are very amplifier friendly, which is most unusual for all-ribbon, full range panels. These world class speakers never drop below a 4 ohm load and have a rated sensitivity of 87 dB. Typically, big ribbon panels like these present sub 4-ohm loads and have only 81 or 82 dB sensitivity. Maybe their contradictory electrical behavior is one of the reasons why these Greek speakers sound so incredibly good. Regardless, because power corrupts, and absolute power corrupts absolutely, we used two of these great Sunfire Signature amps; one dedicated to each Omega panel.

Having so much power on tap makes for a maximo musically satisfying performance. You have no idea what you are missing, even if you're running a supposedly mighty 200-watt per channel transistor amp. Because transistor amplifier clipping is so insidious, most of us have become subconsciously used to a hard clipping reality -- Until you run 600 Niagara-style watts a side. It's like snapping up a musically veiling shade. A rich chromatic sunlight of deep musical expression suddenly shines through. (Tube amps, because they clip so gracefully, don't have this particular sonic downside.)

Once we had satisfied ourselves that home movies and the Sunfire True Subwoofer Signature could shatter the Waterford, terrorize the neighbors, and vibrate our booties like no other sub, it occurred to us to try it out in a pure music making role. This was a big gamble of our time and energy, given the only so-so results we had with the Analysis Omegas and the Hsu sub. But hey, that's what we don't get paid for. Well, step right up and lay down your bets, folks, because today is your lucky day! The all-American Sunfire True Subwoofer and the Greek born Omegas intoxicated us like a warm Metaxa brandy washed down with an ice cold Bud.

To get the best stereo results, we found that we had to move the Sunfire True Subwoofer out of its corner, and to a position midway along the front wall, about 16 inches behind the Omegas (which are positioned almost a third of the way into the room.) We also changed the Video Contour switch setting to Flat, which, instead of starting the sub to rolloff at 30 Hz, extended the Sunfire True Subwoofer's output down to 16 Hz. For stereo music in our setup, this configuration produced the flattest and best-integrated deep bass.

However, the sub's optimal crossover setting still remained at the factory marked "Normal/65 Hz" point. This is most probably because the True Subwoofer's RCA output into the two Sunfire Signature amps has a high pass filter cutoff of 70-Hz with a 6-dB octave slope. This stereo setup also put the Sunfire True Subwoofer's crossover smack in the middle of the musical chain. Poor crossover electronics can quickly foul up the sound in a very bad way. Wonderfully, the overall sonic result was as squeaky clean as a Southern Baptist minister at Sunday services even though the rowdy Sunfire sub was in the center of this jump-up musical sermon.

The Analysis speakers ran unfiltered off the Theta outputs, using only the True Subwoofer's high/low pass filters. Running the stereo speakers full range also allowed us to use the Casablanca's beautiful sounding Analog Direct mode (to use the Casablanca's bass management system, you have to exit its ultra pure analog direct scheme and enter the digital processing domain). We thus kept out all the bad binary musical troublemakers.

We only encountered one glitch when hooking up the Sunfire in this new stereo configuration. Strangely, it happened with the Nordost SPM interconnects used to connect the True Subwoofer to the Casablanca. On two separate occasions, the pin inside an SPM's RCA shell pulled right out when disconnecting the wire from a component. In one case, it necessitated our returning the first True Subwoofer review unit as the SPM pin got impossibly buried inside the sub's RCA jack. In another occurrence shortly after, an SPM RCA pin got lodged inside the Theta Casablanca. Fortunately, this SPM pin wasn't lodged so deep that we couldn't pull the offending thing out of the Casablanca's RCA jack. These two back to back SPM mechanical failures were very troubling. However, Nordost did replace the two broken interconnects free of charge. Still, these two separate SPM failings raise some troubling questions about the long-term reliability of these otherwise excellent interconnects.

But hey, let's move on to happier subjects, like the amazingly transforming effect the Sunfire True Subwoofer Signature had on our already excellent stereo rig. First, the musical presentation put on by this joined at the hip speaker combo was as smooth and seamless as a Farah Fawcett facelift. This was very different from our experience with the Hsu sub, which is a terrific product, but just didn't mate well with the Omegas, for whatever reason. With the True Subwoofer pumping away in its position midway along the front wall, it was impossible to ascertain the source of the low notes. One had a thoroughly convincing illusion that the deep bass, when called upon, issued forth from its proper place on the soundstage. There was absolutely no subwoofer localization problem. It was so invisible it was almost eerie.

And when the Sunfire True Subwoofer was supposed to be dead silent, it was as quiet as a silk nylon dropping on the floor. But Yikes! When Paul Reido pulled out all the stops of the fifty foot high Lay Family Concert Organ in the stupendous CD "Pomp and Pipes" [Dallas Symphony Orchestra, Reference Recordings RR-58CD], our apartment walls nearly did a Jericho, come blow your horn, tumbling down act. Meanwhile, the neighbors' pets plotzed, and our guts rumbled in deep organ syncopation. This was deep bass with a vendetta vengeance. The Sunfire True Subwoofer will gleefully wreak havoc on anything that isn't safely stowed.

Fortunately, this sub's pitch definition on music was superb. One CD we always use to check out how well the bass vowels are being formed is "Talking Timbuktu" featuring Ry Cooder and the great Ali Farka Toure [BMG D103178]. This rhythmically infectious world music CD prominently features soul-banging congas. On medium quality systems, the congas sound overly ripe. On bad systems, they become banana mush. But on the Sunfire True Subwoofer, the conga drums' pitch definition and instrument solidity were exemplary. Call this a sumptuous banana split. The tonal decay as the conga slaps died away was also exactly right.

But something really X-Files strange happened to all our music with the Sunfire True Subwoofer in the loop. The soundstage abruptly grew to gigantic proportions. The front speaker wall was blasted into the next door neighbor's apartment, scattering dishes, dogs and dust in its path, and straight on almost into the next unit. The incredibly increased sense of space was a Muldar-you're-not-going-to believe-this shocker. Dipole ribbon panels are famous for their great spatial quality, which is one of the reasons we like them so much. So for the Omega panels to become even better at this sonic magic act is to really say something.

Moreover, imaging and localization didn't get lost in this vastly increased acoustic space. In fact, both of these desirable qualities were now considerably better. The Robbins family could have used one of Carver's subs to find their way back home. The Apogee Caliper/Hsu combo, while very good, never produced this kind of system apotheosis. Even Fox Muldar couldn't find an answer to this bizarre but wonderful phenomenon, so we're not even going to try.

Finally, the amount of new musical detail was similarly astounding. At least we can probably explain this particular marvel. Our hunch is that the Analysis Omegas, full range though they are, were still doubling and distorting down in the nether regions. This had an injurious effect on the overall tonal character and quality of the system. However, with the deep bass removed from the Omegas, they worked much less hard and distorted way less. Freed of their bass-heavy load, the Omegas could blissfully concentrate on what they did best. The Omega's midrange and top end took on a magical sheen.

Needless to say, all the CDs we thought we knew so well took a deep breath of new musical life with the Sunfire sub in the system. For example, "Blue Skies" [John Mark Records, JMR 9) just blossomed. This is a marvelous, well-recorded jazz CD featuring Harry Allen on tenor sax playing with his eponymous quartet. The deep currents of highly detailed air flowing out and around Allen's group were strong enough to blow out an octogenarian's birthday candles [By the way, John Marks Records is a small Indy label that deserves your support. Marks has put together a fine catalog that also includes very good classical work. Check out his web site at]

One really good example of the vastly improved imaging, soundstaging, and musical detail was found in Carl Orff's Carmina Burana, stirringly rendered by the Leipzig Orchestra under Herbert Kegel. This CD also happens to be an equally fine recording [Philips 420 713-2]. Carmina Burana features a huge chorale and many lets-show-our-stuff opportunities for both male and female soloists. The opening bars, of course, are an orchestral exercise in lets get really busy and big. A system that doesn't measure up will just wimp out and die on the work's first few notes. Not so the Sunfire True Subwoofer/Omega duo. They toed the line, stuck out their musical jaws and dared Kegel to do them harm. But instead of a sloppy food fight, everything joined together in a stirringly reproduced piece that extended down the block, around the corner, and all the way to Fenway Park--and you always knew exactly where everyone and everything was in this huge medieval musical procession. Outstanding.

At $1,895, the Sunfire True Subwoofer Signature ranks as a bargain in the high-end scheme of things. Remarkably, it elicits a very refined, detailed, hugely spacious performance from a high-end stereo rig while conveying a seemingly bottomless musical presence. You could easily blow way more dough and get a lot less in return.

The Sunfire True Subwoofer Signature can also blow your action movie-addled brains out during the big boom-booms. This LFE rocket launcher is the ultimate don't-mess-with-me bad boy of subwoofers. Everything else might be Falling Down during the movie, but not this sub's explosive performance.

So what more do you want, besides two of them?

Copyright 1998, Francis Vale, All Rights Reserved

This article appeared in the Winter 1998 Issue of 21st

21st, The VXM Network,