The Sunfire XTEQ12 brings back a fond memory for me: seeing the press release for the first Sunfire subwoofer, back in 1995. It pictured Sunfire founder Bob Carver, holding his new miniature subwoofer and standing outside his nondescript company headquarters, with power lines and pine trees in the background. That original Sunfire True Subwoofer--a combination of a beefed-up driver and passive radiator, Carver's cool-running Tracking Downconverter amplifier, and a bass-boost circuit to compensate for the sub's tiny enclosure--changed the audio industry. It was widely copied, and its influence can be seen in practically every subwoofer sold today.
The new XTEQ Series subwoofers barely look any different from the original, even though Carver is long gone from the company. The top-of-the-line, $2,000 XTEQ12 features a 12-inch driver, a 12-inch passive radiator, and a Tracking Downconverter amp rated at 3,000 watts. The line also includes 8- and 10-inch models.
The big difference between the XTEQ Series and the original Sunfire subs is an auto EQ function. Plug the included test microphone into a jack on the back of the sub, put the microphone where your head will be when you're in your favorite listening chair, and hit the start button on the back of the sub. The sub then automatically steps through four tones (35, 49, 64, and 84 Hz) and uses the signal from the test microphone to EQ itself automatically, thus optimizing its response for your room acoustics. You can also EQ the sub manually, although this function is limited; all you can do is bump any of the frequencies up by +6 dB. Either way, a tiny switch on the back panel lets you turn the EQ on and off after it's set.
Of course, auto EQ is built into most AV receivers. However, if you don't like the results of your receiver's auto EQ, or if you're using the XTEQ12 in a stereo system with no auto EQ, this feature could come in handy.
The XTEQ12 is a nicely finished cube that's fairly heavy for its size. On the bottom, it has four Anti-Walking Tread Design Feet, which are intended to keep the sub from scooting around on tile or wood floors as it vibrates.
The XTEQ12 offers some unusual and welcome hookup options. You can do the usual line-level run (via RCA or XLR cable) from your receiver or preamp/processor. Or you can feed line-level signals via RCA cables from a stereo preamp to the sub, then run those signals straight out to your amp--and, if you like, employ the XTEQ12's switchable 85-Hz high-pass filter to cut the bass out of the signal that feeds your main speakers. This feature makes it easy to use the XTEQ12 in a stereo system with a pair of mini-speakers. With most subs and stereo systems, you'd have to run the mini-speakers full-range, in which case you're almost certain to get bass distortion and likely to get less life out of your speakers.
I used the XTEQ12 with a Klipsch Reference system based around the RP-280FA towers. I used two sets of electronics: a Denon AVR-2809Ci receiver connected to an AudioControl Savoy multichannel amp and a Pioneer Elite SC-89 equipped with Dolby Atmos. I used a subwoofer crossover point of 80 Hz, so the sub would have to handle most of the bass on its own, without help from the tower speakers' woofers.
I was surprised to notice a heat sink on the bottom of the sub. Past Sunfire subs I've reviewed didn't have this, and I was under the impression that the Tracking Downconverter amp (which is essentially a Class G/H design) runs cool enough that it doesn't need an external heat sink. This heat sink has tiny fins that are about a quarter-inch high, and it's recessed into the bottom of the chassis, so it gets little airflow. The sink gets quite hot and sits close enough to the ground that the fins left an impression in my low shag carpet. The heat didn't damage my carpet; but, if I had an expensive carpet, I'd be worried.
By the way, it's a good thing those Anti-Walking Tread Design Feet are there, because this subwoofer does a lot of shaking back and forth when it's playing deep bass notes.
The first thing I had to do was test the auto EQ and see if I should use it during my review. These systems don't always work as advertised; one manufacturer actually recommended that I not use his sub's auto EQ, which was developed not by his company but by whichever company manufactured the sub's amplifier. So I played a couple of tunes with melodic bass lines--Steely Dan's "Aja" and the live version of James Taylor's "Shower the People"--to see how the sub performed in my listening room's "subwoofer sweet spot" without the EQ. Then I ran the EQ, which takes just a couple of minutes, rechecked the subwoofer's level in the receiver, and listened again.
The difference was pretty obvious. The auto EQ didn't radically change the sound, but without it, some notes in those tunes' bass lines were a lot quieter than others. Given the excellence of the bass players on these tunes, and the amount of processing and compression used in the mixes, I think it's safe to say these lines are supposed to sound almost perfectly even. With the auto EQ in, every note in the bass lines came in at about the same level, and the lines sounded smoother and more melodic as a result. I left the auto EQ turned on for most of the rest of my evaluation, switching it off only briefly on a couple of movie scenes where I wondered if the EQ was reducing the output a bit.
In fact, tunes such as these (and Toto's timeworn classic "Rosanna") are where the XTEQ12 shines. Once you hear a well-produced, slick musical performance like these through a sub that's been EQed for your room, it's hard to go back to a sub that's running without EQ. The groove of the tune is better because the bass doesn't drop out on certain notes, and you can get a better sense of the tune's harmony, too.
I could hear this advantage even more on Holly Cole's "Train Song" from the Temptation CD. The tune starts with deep notes from an upright bass. Through the XTEQ12 without auto EQ, it sounded fine, about like what I'm used to hearing. With the auto EQ, the notes were more even, and I also seemed to get a better sense of the "growl" in the upper harmonics of the notes.
You won't notice this improvement in every tune; when I played the intro to "Detour Ahead" from disc three of the Bill Evans Trio's The Complete Village Vanguard Recordings 1961, bassist Scott LaFaro's opening notes sounded hardly any different with auto EQ. Why? Because a subwoofer crossed over at 80 Hz is handling only the fundamental tones of the bottom 13 or so notes of a standard bass. Your main speakers handle all the harmonics, plus the fundamentals of all the middle and upper notes.
This even response in the second octave of bass (40 to 80 Hz) did nice things for movie soundtracks, too. When I played the scene from the Interstellar Blu-ray disc where the ship first enters the wormhole, the intense midbass vibrations came through beautifully, giving me a convincing sense that I was inside a metal vehicle on the verge of being shaken apart. Later scenes, such as the one where one of the spaceships is struck by colossal waves, also gave me a powerful sense of the bass vibrations in the soundtrack.
Click over to Page Two for The Downside, Measurements, Comparison & Competition, and Conclusion...