Subwoofers are hard. They’re not only hard to design but also hard to integrate with your audio system. Despite what they call their products, most manufacturers don’t really sell subwoofers. Instead, most so-called subwoofers are actually woofers. Woofers handle frequencies from about 200 Hz. to about 30. There are multiple advantages to making single-woofer systems: It’s cheap, the satellite speakers can be smaller, and it makes for a good spouse-acceptance factor.
True sub-woofers are harder. Intended to augment speakers that are already full-range, sub-woofers then add the bottom octave or more of bass. Technically, this frequency range is from about 40 to 20 Hz. or lower. To produce these subsonic frequencies with authority, the sub must have large radiating area, high amplifier power, and a large enclosure. Most manufacturers “cheat physics” by using an extremely powerful amplifier in a small enclosure with a small driver that has extreme excursion capability.
There are many reasons why this is not a good idea. First, if a subwoofer is to be good, it must go really low. Most small subwoofers can't. Second, for a subwoofer to work with music and not just movies, it must have a flat frequency response across its range. Most small subwoofers don't. They're tuned as "one note boom boxes" for impact on movies and really don't sound good on music because they lack pitch definition. Third, most of the small-enclosure, high-excursion subwoofers distort like crazy. The long excursion creates tremendous amounts of intermodulation distortion, and the highly resonant box/driver system keeps ringing long after the signal has stopped.
Most subwoofers that are truly capable of performance below 20 Hz don’t function well as woofers. The subs’ large-diameter drivers are just too heavy to reach frequencies much above 40 Hz. without sounding slow and mushy. This prevents a seamless blend with the main speakers.
One of my favorite “bass-test” cuts is from the movie soundtrack “The Commitments.” Their version of Wilson Pickett’s “In the Midnight Hour” begins with a trumpet fanfare followed by a well-recorded kick drum, bass guitar, and tenor sax. Speaker/sub combinations that aren’t crossed-over properly fail to make these sound realistic. With a proper crossover and a good subwoofer, the bass guitar sounds visceral, the drums have both weight and pitch, and the tenor sax sounds fat and sassy. The bass also should sound like an integral part of the recorded ambience.
Another fave cut is Lou Bega’s “Ice Cream.” The bass chorus line here should be startling, full, and spread out in the room. If it sounds boomy or lacks pitch defnintion, then there are problems.
Just about any properly made recording of the plucked acoustic string bass will test subwoofer pitch definition. If all the notes sound the same, then the sub is unable to render pitch well, usually because of “theater tuning.”
A well-recorded drum solo can be used to test subwoofer overhang. If the sub has problems with overhang (the inability to go immediately silent after the signal stops), the drums will sound muddy with insufficient differentiation between the strokes. Most subwoofers that are designed primarily for home theater use also flunk this test badly.
Electronic synthesizers can also be used to test overhang. Because the synth can cut off abruptly (unlike a drum waveform that decays more slowly), the sub overhang problems can be detected more easily. Good synth test cuts include material by Kraftwerk, Wendy Carlos, and/or Don Dorsey.
Unlike many, I don’t listen at outrageous volumes (well, maybe on special occasions…). The majority of listening was conducted at or below 90 dB. Because of my room size (20 x 15 feet with 9 foot ceiling) and shape (multiple doors, one stairwell, one foyer opening, and two hallway/kitchen openings), standing waves were not as big an issue as they might have been in a more conventional room. The subwoofer phase was adjusted using both Emotiva’s proprietary room tuning system (Emo-Q) and by ear using the music listed above. Ultimately, I preferred the sound without the Emo-Q.
DEFINITIVE TECHNOLOGY TRINITY SIGNATURE SUBWOOFER:
This subwoofer uses two electrically driven 14” radiators along with four passive 14” radiators. Normally, 14” speaker cones are so heavy and slow that there would be little chance of mating them with any high-quality speaker (at any crossover frequency higher than 40 Hz.) without muddy bass. The Trinity avoids this problem by having a HUGE amount of radiating area.
A typical subwoofer with a 12” effective driver size offers 123 square inches of radiating area. The Trinity, by contrast, has 924 square inches – seven and a half times as much! With the increased radiating area, the cone excursion required to produce the same acoustic wattage is dramatically reduced.
The Trinity’s small cone excursion reduces intermodulation distortion and makes the sub sound significantly “faster” than other subwoofers. This apparent speed allows a seamless mating with delicate sounding speakers such as planar magnetics, electrostatics, and top-quality dynamics. Therefore, unlike most true sub-woofers, the Trinity can also be used as a very good woofer. Cross the Trinity over at higher frequencies, and it will still sound quick and blend well.
As to the Trinity’s frequency response, DefTech claims that the subwoofer “responds to” signals as low as 10 Hz. This is like saying that because I’m a male, women respond to me like Brad Pitt. The Trinity may, indeed have drivers that will respond to a 10 Hz. signal, but that response would certainly be at least 12 dB down from the Trinity’s mean (average) sound pressure level. Keeping in mind that the decibel scale is a logarithmic scale, and that each six decibels represents a drop of 50% in sound pressure level, a -12 dB level reduction means that the signal at 10 Hz is only about 25% as loud as the rest of the sub’s output. You’ll never hear (or feel) 10 Hz. from this (or any other) subwoofer.
The “DefTech Haters,” and for some reason there is a plenitude of them in online forums, claim that because this single specification is fudged, that the entire Definitive Technology company and all of its products are suspect. I’m not entering that fray, but I will point out that, unlike loudspeakers, there is no standardized way of measuring subwoofer response. Should the response be measured with the sub:
There is no standard. Regardless of the ethics, printed specifications sell products and DefTech takes liberal advantage of that fact.
I could not test the low bass of my Trinity below 16 Hz. I have no signal generator, and the lowest tones on any of my recordings are the organ works by Bach (Toccata and Fugue in D-minor) and by Charles Marie Widor (Organ Symphony). I also have DJ Magic Mike’s “You Want Bass?” With any of these, the sub not only rattled my china, but also rattled the china of my neighbor whose house is separate from mine and on its own lot ( ! ). The lowest pressure waves could be felt, but not heard.
In my room, I have full-range main speakers (Thiel 3.6) with honest -3dB points of 36 Hz. I tried running my Thiels full range and cutting in the Trinity at 40 Hz. This worked fairly well, and the sub was inaudible unless subsonic frequencies were actually present. The transition was close to seamless, and there was a good, but not perfect blend between the Thiels and the sub without gross crossover artifacts. There was, however, a sense that something didn’t sound quite right.
There may be a slight discontinuity at the crossover frequency (or may not) caused by slope asymmetry. Such asymmetry is usually caused by the combination of the electronic crossover’s roll off combined with the acoustic roll off of the main speakers. Some electronic crossovers allow tailoring of their slopes. Unfortunately, most consumers lack the knowledge to use the feature.
For the fun of it, I also tried crossing over the Trinity into my system at an octave above the Thiel’s -3dB point. This put the crossover frequency at 80 Hz. WHOA – what a difference!
The Thiels, now relieved of the necessity to play (and sometimes play loudly) at lower frequencies, came alive with a previously unheard “jump factor.” The Trinity, with its massive radiating area and low intermodulation distortion, sounded very fast, full, and lively even at the higher crossover frequency.
With the 80 Hz. crossover point and “normal” music, the subwoofer mated seamlessly with my Thiels and provided not only a more full and natural presentation than the naked Thiels but also truly excellent pitch definition. The Trinity, as stated earlier, is an outstanding woofer. Both initial attack and signal cut-off are crisp and clean without overhang. I left the crossover point at 80 Hz. for the remainder of my listening.
As a sub-woofer, the Trinity works as well as many far more expensive subwoofers. I make this statement based on my recollections of multiple auditions over the years in dealers’ showrooms. As a woofer, however, the Trinity bests all other subs that I’ve ever heard or previously owned. This “previously owned” category includes some very good subs including the M&K MX-350 THX, the big Velodynes, and the Definitive Technology Supercube I. I’ve also owned many “consumer grade” subwoofers including models by Polk, Klipsch, and JBL.
See the Trinity specifications here: http://reviews.cnet.com/subwoofers/defin....7-33578412.html
So is the Definitive Technology Trinity “the best subwoofer in the world?” I would have to say no. In spite of the technical advantages of the design, it lacks the ability to tame the one thing that can make or break a subwoofer – the sound of the room where the sub is being used.
Listening rooms exhibit extreme standing wave problems that produce peaks and dips in the bass frequencies. Subwoofers strongly excite these standing waves leading to severe boominess and ragged frequency response. Even the flattest, cleanest subwoofer in the world can’t sound its best in a typical listening room.
Receiver-style room equalization systems such as the ubiquitous Audissey, the proprietary Yamaha YPAO system, and the proprietary Emo-Q help but they can’t really do a good a job of equalizing a subwoofer to the room. Why? Because they lack the narrow equalization banding that is needed to tame low-frequency room resonances.
Many subwoofers now come with their own, bass-only equalization microphones and calibration software. DefTech’s newer line of subs has this technology. Every other “super-subwoofer” has this feature as well. I’d be amazed if DefTech’s engineers aren’t burning the midnight oil to add room-correction to their Trinity subwoofer. I hope that DefTech will also make their equalizer a stand-alone unit that can be retrofitted to existing Trinitys!
One suitable bass equalizer that I’ve read about is the DSPeaker Anti-Mode Subwoofer Equalizer, model 8033. This unit was reviewed in “The Absolute Sound” magazine issue #204. I haven’t heard this equalizer, but I have good confidence in the opinion of Mr. Robert E. Greene, the reviewer. The online review is available here: http://www.theabsolutesound.com/articles....alizer-tas-204/
If you’re already spending the $$$ for the DefTech Trinity, there’s no good reason not to pony up the additional money for a bass equalizer. With such an equalizer, then yes, the DefTech Trinity probably IS “the best subwoofer in the world.” It is certainly the least expensive “super-sub” that one can buy (even including the additional cost of the equalizer).
Watch for closeout sales on the un-equalized Trinity. Definitive Technology Corporation will almost certainly discontinue it soon when their equalized version is available.
The Definitive Technology Trinity Signature subwoofer is not only one of the best sub-woofers in the world but also an exceptionally fine woofer. The Trinity misses “best in the world” status only by its lack of dedicated room equalization. I know of no other subwoofer that provides the speed, pitch-definition, and musical finesse that the Trinity does. Highly recommended!
Reviewed September 2012 – by Boomzilla (Moniker not indicative of listening preferences!)
Equipment used in this review: