Associated Equipment:
Front End
Digital Front End
A Blessing in Disguise


March 2007


In the Beginning
Let me begin with what is now an oft-told tale. In the early days of audio, amplifiers were tube-based and of low power. The speakers they powered were, by necessity, of high efficiency/sensitivity, often incorporating horns. The introduction of the transistor dramatically changed the landscape as it became possible to obtain higher power, and to do so relatively inexpensively. With the availability of higher powered amps, speaker designers no longer had to be concerned with efficiency. Horns were slowly replaced by conventional dynamic driver designs, which used multiple drivers and more complex crossovers. The popularity of this approach is apparent from a quick visit to most any high-end audio store, and by the success of brands such as B&W, Thiel and Wilson.

However, as time passed an increasing number of audiophiles became disappointed with this supposed advance. While the new breed of speakers and amps had greater frequency range and lower distortion than earlier designs, many listeners found that the former lacked the ability to communicate the emotional content of the music. Thus began - - first in Japan and later in the United States and Europe -- a resurgence of simplicity, as manifested by single-ended triode (“SET”) amps and high efficiency speakers. The subject of this review, the Teresonic Ingenium loudspeaker, is a high efficiency speaker utilizing a single driver (and thus no cross-over).

The Speakers
Teresonic is a relatively new company which presently sells only direct to the consumer. Their product line comprises two models, the smaller Integrum and the larger Ingenium, each of which utilizes a single Lowther driver. The Ingeniums come standard with a Lowther DX3 driver, though the DX4 is available for additional cost. The model I reviewed had the DX3. While Lowthers are typically described as being full-range drivers, they are not actually so in the sense that they do not cover the entire range from 20 to 20,000 Hz. Accordingly, one must utilize an appropriate cabinet to increase their output, especially at the lower frequencies. Teresonic uses a modified transmission line design which they refer to as ETQWT™ (Enhanced ed Tapered Quarter Wave Transmission line) with Helmholtz resonators. Unlike many modern speakers which aim for an absence of cabinet resonance, the cabinet of the Ingenium is “tuned” like a musical instrument to introduce its own resonances and overtones, and to cancel out some unwanted peaks associated with the Lowther driver. As expected, rapping on the side reveals a resonant cabinet.

The Shortest Distance Between Two Points...
The original plan was for me to review the smaller Integrum. Once en route, Teresonic provided me with the tracking number so I would know when to expect delivery. When the speakers didn’t arrive as scheduled I contacted the courier and was assured that they would arrive the next day. To make a long story short this episode repeated itself daily for almost two weeks, at which point the carrier acknowledged that one of the two packages was missing. After still more calls I learned that they had found the missing package but that it had been damaged. Back to the manufacturer they went. Mike Zivkovic at Teresonic quickly dispatched a brand new set of speakers to me, this time a pair of Ingeniums to make up for the aggravation (which of course, was not his fault). The Ingeniums arrived promptly. I was delighted to see learn that Teresonic packs their speakers in specially constructed crates (one speaker per crate). How the carrier managed to damage one of them (in the first shipment) will remain one of life’s mysteries. Within the crates the speakers are further protected against scratches by a material sack, and the speaker wires come in beautiful wood boxes. All-in-all packaging is handled extremely professionally.

Unfortunately, upon unpacking the speakers and setting them up, it was immediately apparent that one of the drivers was damaged as it emitted a terrible buzzing sound. Because of their very high tolerances, it is not uncommon for the Lowther’s voice coil to become misaligned. I tried to realign it (with the help of friend and audio dealer who is quite familiar with Lowthers) but the driver continued to misbehave, so Teresonic sent me a brand new matched pair of drivers. Kudos to Mike for keeping such a cool head during these mishaps. The drivers were easy to install, and have thankfully performed without incident. If this proves to be a recurring problem, the folks at Teresonic might want to consider shipping the Lowthers separately from the speakers and letting the customers install them.

Looks Do Count
I pride myself on choosing audio components for the way they sound, not the way they look. In fact, some of the best components I have owned have been rather mundane looking. That said, the Ingeniums are downright gorgeous, and it is difficult to not be smitten by them. The fit n’ finish is world class, and their shape is everything I am not - - tall and slim, with beautiful flowing lines. I imagine they will win admiring glances in any setting. The front face is magnificent rosewood, while the sides are black. The Ingeniums are 73” tall, 10” wide and 20” deep. They form a gentle “S” with the driver mounted approximately in the middle of the vertical axis, on the front convexity. The transmission line opens at the bottom front. The binding posts are on the back opposite the drivers; and are thus some distance from the floor; this geometry must be taken into account when calculating the required length of speaker wire. Speaking of speaker wire, I used both my reference Stealth Audio MLT hybrid wire, as well as Teresonic’s own Clarison speaker cables for this review. With a sensitivity of greater than 100 dB, the Ingeniums will of course be quite sensitive to extraneous noise. With both brands of speaker wire I had only the slightest hiss through the speakers, which was inaudible from the seating position.

Positioning the speakers was a trade-off between bass response and soundstage depth. In their final position, the front face of the Lowther was 51” from the front wall, and 38” from the side wall. The centers of the speakers were approximately 8 feet apart, and I sat 8-10 feet away from the speakers (measured on the diagonal). I preferred them with no toe-in.

The Sound
As noted above, the review speakers had brand new Lowthers. If ever there was an audio component that required extensive break-in, it is the Lowther driver. Right out of the box, the sound was awful. As in dreadful. As in “what-the-heck-is wrong with these things?” Think thin and screechy. But with time things changed dramatically, all for the better. As of this writing I have played them for a few hundred hours, and it is unlikely that the Lowthers are yet completely broken in. Anyone who buys these speakers should keep in mind the long break-in, lest you jump to an incorrect conclusion. Considering that the Ingeniums use but a single driver and lack a cross-over, it is hardly surprising that their sonics reflect the characteristics of that driver, for better and for worse. The Ingenium’s strong points are considerable and can be summed up in a just a few words: Speed. Palpability. Coherence. Lowther drivers are praised the world over for their startling midrange, and the Ingeniums exhibit this property to its fullest. To listen to the Ingeniums is to be reminded of just how compromised many (most?) speakers are in the all-important midrange. Let’s start with speed.

Audiophiles often speak of dynamics, which refers to the range between the softest passage and the loudest. While frequency range of the speaker obviously has an impact, so does the ability of the speaker to respond quickly to dynamic changes. In fact, I feel that speed is arguably more important; given the choice, I would choose a fast speaker with limited frequency range over a fuller-range but slower one. In considering dynamics it is useful to distinguish between macrodynamics and microdynamics. The former refers to the change in volume from a soft passage to a loud one, whereas the latter refers to the structure of an individual note: its rise, sustain and decay. Whereas macrodynamics are more ear-catching, microdynamic structure is equally important to realistic musical reproduction. Far too many systems are simply too sluggish to properly reproduce a note. The Ingeniums on the other hand are lightning-fast. Be it the pluck of a string, the thwack of a stick, or the breath into a horn, the Ingeniums reproduce the sound with startling realism, imbuing the music with life and energy. By comparison, many other speakers seem dull and lifeless.

Which brings us to palpability and coherence. A problem facing any designer of multi-driver speakers is that of driver integration. Some designers succeed admirably; others fail miserably, while most fall between these two extremes. In the worst cases, the discontinuity between drivers is readily apparent due to different tonalities and/or dispersion. In the best of cases, it is barely noticeable - - until one listens to a single driver speaker such as the Ingenium. Through the Ingeniums, music is reproduced as a coherent whole, rather than as a bunch of pieces being fit together. We have all experienced live music in which the band is “tight.” We have similarly heard performances in which the various performers just didn’t seem to be on the same wavelength (pun intended). It is my belief that what accounts for this disparity relates to timing. When a band is tight, the musicians are playing in perfect unison, and often seem as though they can read each other’s minds. While I am loathe to make too strong a comparison between live music and that which is recorded and reproduced, I feel that the analogy is reasonable. Music played back through the Ingeniums is akin to hearing a tight band - - all the parts seem properly connected. In conjunction with their speed, this property made the music sound more life-like than with virtually any other speaker I have heard. High praise indeed! One could almost see the musicians smiling as they played off one another; some times harmonizing perfectly, other times intentionally slightly off beat, and still other times with perhaps a bit of one-upmanship. I cannot over-emphasize that this is not just about correct tonality, or harmonic lushness, but something far more intrinsic to the music. As with pornography, when you hear it, you know it. And once heard, one immediately understands why designers of crossover-less, single driver speakers are so adamant about the importance of this approach.

Of course, the Ingeniums allowed me to hear very deeply into the music. This was not the kind of treble highlighting that certain speakers display but rather, an incredible portrayal of the instrument’s harmonics. When listening in particular to string instruments, I had a greater sense of the body of the instrument than with most other speakers. As mentioned above, Lowthers greatest strength is in the midrange. The human voice falls predominantly in this frequency range, and through the Ingeniums it is magnificent. Listening to well recorded vocal recordings through the Ingeniums was always a treat. They were at once dynamic, full-bodied, and vivid; truly a sublime experience. The soundstage produced by the Ingeniums was of reasonable width and depth. Where the Ingeniums excelled was in the layering of the instruments. This was not the kind of phony imaging in which one can draw imaginary lines around the instruments. Rather, it was more a sense of each instrument occupying its own sonic space. This too added to the realism. Are the Ingeniums perfect? Of course not, no speaker is. Their weaknesses are in two main areas. First, although Teresonic lists the specifications of the Integrum as 30Hz-22kHz ± 3dB, my ears tell me that the frequency response was considerably narrower in my room. (The transmission line is, I believe, tuned to 35 Hz.) The high frequencies did not have the air and sparkle I am used to from, for example, my reference Horning Agathon Ultimates (which have a tweeter), nor did the bass go particularly low. The lack of high frequencies, while noticeable, did not bother me a great deal. (I believe that the output of the DX3 drops off dramatically above about 13,500 Hz). Moreover, substitution of the DX3 by the DX4 will somewhat lessen this problem. The lack of lower frequency energy was more of a problem, as some recordings sounded a bit thin. While this is obviously highly room-dependent, purchasers of the Ingeniums should consider augmenting the bass with a subwoofer. I should point out that this is the case with other well-regarded single driver speakers, for example those from Beauhorn, Cain & Cain, or Rethm.

The second problem is that despite the designer’s best efforts, the Ingeniums retained some of the “Lowther shout.” This manifests as an unpleasant peakiness, the degree of which varies with recording and type of music. This was somewhat ameliorated by use of the optional phase equalizer, which I used for most of my listening. Not surprisingly, the shout is more apparent with digital recordings than with those on vinyl, and with electronically amplified music - say, rock and roll- than with acoustic music such as blues and other small ensembles. In fairness, there are a number of caveats that must be mentioned. First and perhaps most important, as mentioned above I doubt that the Lowthers are yet fully broken in. It is well known that as the drivers break in, the shout diminishes. Second, individuals differ considerably in their sensitivity to high frequency distortion; I happen to be exquisitely sensitive. Third, my amplifiers, the Tube Distinctions Soul monoblocks which use parallel single-ended KT88s for the output, are quite revealing. Pairing the Ingeniums with a warmer sounding SET amp will undoubtedly diminish the shout, albeit at the expense of some clarity and frequency extension. Fourth, for pyschoacoustic reasons, increasing the bass with a subwoofer will tend to make the shout less apparent. As such, the shout I experienced should not be deemed a deal-breaker and in fact, may prove to be at most a minor weakness.

Concluding Remarks
Unlike woolen winter hats, when it comes to speakers one size does not fit all. Much as we would like to pretend otherwise, no speaker does it all. Not only must one take into account the relative physical sizes of the speaker and room, other factors such as musical taste and sonic priorities must be considered. For example, while very large speakers such as the Nola Grand Exotica or the Dali Megalines excel at reproducing orchestral music in all its splendor, they are less adept at conveying the subtleties of softer musical pieces. In contrast, a speaker such as the venerable Quad 57 is amongst the best ever made in reproducing smaller ensembles, but is simply incapable of the larger SPLs and frequency range of more majestic pieces. The Ingeniums are closer to the Quad in this regard. They provide exquisite reproduction of vocals and acoustic music, be it folk, jazz or chamber. With such music the realism they provide is uncanny, and superior to that of many speakers on the market. The Ingeniums provide an emotional connection to the music that truly must be heard to be believed. On the other hand, because of their somewhat limited frequency range, and a bit of edginess (but see caveats, above), they are less suited to electronic music such as hard rock. Fortunately, it is unlikely that those who prefer such music would opt for a single-driver speaker.

Their retail price of approximately $9,975 (not counting a subwoofer) is hardly insignificant, and many excellent speakers are available at this price point (or lower). That said, the Ingeniums bring to bear the great strengths of the Lowther driver in a stunning package, and will provide hours of listening pleasure for those whose tastes are aligned with their design goals. Now that they are on the way back to the manufacturer, I will most assuredly miss them.

Laurence Borden

One-way floor standing dynamic loudspeaker
Enclosure type: ETQWT™ transmission line with Helmholtz resonators
Drive unit: One 8” Lowther DX3 driver
Crossover/Filter: None
Bandwidth: 30Hz-22kHz ± 3dB
Sensitivity: 101.5 dB (1W/1kHz/1m)
Impedance: 8 Ohms
Crossover: None
Power handling: 4 - 100 Watts into 8 Ohms
Connections: WBT gold plated terminals
Internal wiring: Zero-interference Clarison cables
Dimensions: H x W x D : 47 x 10.5 x 20in (122 x 26 x 51cm)
Net weight: 70 lb (32kg)
Shipping weight: 74 lb (34kg)
Accessories supplied Spikes & floor discs – gold finish, adjustable
Speakers grill – black cloth, removable
Cabinet Real wood finishes: Rosewood/Black (other colors available as special order)

Price: $9,975.00

Teresonic™ LLC
1215 Fiddlers Green,
San Jose, CA 95125