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as reviewed by John Beavers
The Teresonic Integrum loudspeaker is a single-driver design using the latest Lowther driver. There are no electronic crossovers or filters of any sort. The speaker employs something called an Enhanced Tapered Quarter Wave Tube (ETQWT) transmission line to help provide a clean, accurate midrange. This design gives extended low-frequency response up to one half-octave below the fundamental resonance of the Lowther driver. Also employed are two Helmoltz resonators, which are acoustical devices that promote a smooth frequency response and remove unwanted colorations and distortions. The resonators are also responsible for correcting the midrange peak characteristics of the Lowther driver.
Teresonic says that the shape of the Integrum speaker is another key factor in producing the sound they have achieved with the design. In their words, “Music instruments are not built as a square shaped box. For a Reason! Conventional box speakers sound like box speakers, ours don't. Form follows function and our enclosures are shaped just like fine musical instruments.” (www.teresonic.com) The sensitivity of the Integrum speaker is 101.5dB. The manufacturer recommends a wide range of amplifier types, from 3- to 4-watt tube amps to 100-watt-per-channel solid-state. The wire used in the Integrum is designed in-house and tuned for the speaker. The manufacturer suggests using both their interconnects and speaker cables, which are of the same design.
All of this sounded intriguing, and though I had had no experience with this type of speaker, I offered to review the Integrums. A good friend of mine, also a reviewer, questioned my wisdom. How can you review speakers of a design that you've never heard? How will you know if similarly-designed speakers are doing the job better or worse? How can you evaluate them using front-end equipment that the majority of those who would be interested in this type of speaker won't have? These were very good questions, and so began one of the most involved and complicated evaluation processes of my reviewing career.
My initial front-end setup consisted of a Reference Audio Mods Level 2-modified Marantz SA11S1 SACD player, which runs off of a battery power supply. The amplification consisted of a Bruce Moore Companion III preamp and Bruce Moore Custom 225-watt monoblock amps run in triode mode at 125 wpc. When I asked Teresonic's Product Manager, Mike Zivkovic, if he felt that my components would work with his speakers, he felt that they would work well enough, but that we would only find out for sure when we hooked up the system. When he brought the speakers over one evening, they looked impressive. They had a beautiful rosewood finish, which had the polished look you'd expect to find on furniture-grade cabinetry. We used only a slight amount of toe-in in the initial setup, which in the long run proved to be best for the speakers in my room. After hooking up the Clarison© interconnects and speaker cables and allowing for some warm-up time for my tube equipment, we sat down to listen. It turned out that my amplifiers were compatible, but my preamp, having 24 dB of gain, gave me only three notches to play with on the attenuator: soft, loud, and very loud. Still, I was able to get a hint of what the speakers could do.
The next phase of the evaluation came courtesy of George Kielczynski, Director of Sales and Marketing of the deHavilland Electric Amplifier Company, who provided the 25-wpc Ios Stereo 845 amplifier that proved to be one of the better matches for the Teresonic speakers, plus deHavilland's UltraVerve preamp. It was this SET amp and octal tube preamp that opened my eyes to the differences between the Integrum loudspeakers and the ones I'd been using most of my life.
One of the most clichéd phrases you can use in describing what an audio product does is to speak of veils being lifted, but in this case it is appropriate. In fact, I heard the absence of a veil. Most speakers have colorations related to cabinet resonances, the crossover design, and the choice of hookup wiring. I could not detect any cabinet resonance in the Integrums, and the rest of what I heard seemed to be in line with the absence of a crossover and the use of very neutral, transparent wire.
My initial impressions were that the Intergrum loudspeakers possessed exquisite tone, transient speed that simply had to be heard to be believed, and stunning levels of ambience retrieval. I had all of this with my reference rig, but it was now more refined. I was enjoying music as I never had before, but a few weeks into the evaluation, I received some feedback from fellow reviewer Larry Borden that brought me back down to earth. While I was indeed smitten by these speakers, my judgment was largely based on hearing high-efficiency, single-driver speakers for the first time. How was I going to effectively describe how the Integrum loudspeakers stood in comparison to other designs of this type?
It is without doubt a unique way to experience music, but I mostly listen to acoustic jazz and blues, and both of these musical genres are well suited to the strengths of these speakers. What about balls-to-the-wall rock‘n'roll or movies? Like most audiophiles, I do not have the luxury of dividing my listening pleasures into two dedicated rooms, nor the funds to do justice to two high-end systems. I have the challenge of trying to deal with all of my sonic pleasures with one system in one space, and need speakers that can do more than one job. Up next—Stevie Ray Vaughn and Lord of the Rings. Would I fall out of love with the Teresonics? Somewhat, but not for long.
You might ask how much bass you get with the Integrum speakers, which are rated at 30Hz-22kHz ± 3dB. I have found that the bass frequencies support the rest of the frequency spectrum in a manner similar to the way in which the roots of a tree feed its branches and leaves. If the roots are too shallow, the leaves and branches suffer. Too deep, and the tree becomes overbearing. Bass is the most difficult thing to get right in most rooms. I had recently completed an attempt to integrate a powered subwoofer into my monitor-based speaker system, and though I had never been completely happy with this kind of arrangement, my attempt was more successful this time. Of the eight subs I tried, the one that integrated the best with the Integrum speakers was the ACI Titan, though the VMPS Dedicated Sub also proved a good match. I would turn on the subwoofer with music that had low bass content, and for movies it was a spectacular matchup. I was enraptured all over again with these speakers. This review was proving to be harder than I expected—I was trying to remain objective, but kept getting pulled into an emotional response. Of course, that says more to me about the quality of the gear I'm reviewing than keeping my feet on the ground. Larry would probably disagree, and speaking of Larry, I still had not answered his question about how I was going to compare these speakers to other, similar ones.
My solution was twofold. I would describe my experiences with as many different amplifier types as I could find, and I would contact another reviewer who is known for his experience with this type of speaker. In getting to work on the first phase of my solution, I went a little overboard, as I'm known to do, and I brought in a plethora of new gear to put the Integrums through their paces. For a contrast to the deHavilland gear, I decided to try some more traditional tube electronics—the Manley Snapper 100-watt monoblock amps and Shrimp preamp. My reference Bruce Moore Companion III preamp, with its 24dB gain, was clearly not compatible with high-efficiency speakers, but the Shrimp, with half that gain, proved to be just right with both the Snappers and the Bruce Moore M225 monoblocks connected to the Integrum speakers. The Manley electronics, though not as dynamic as either the deHavilland or the Bruce Moore gear, was seductive in other areas. It sounded slightly warmer, more relaxed, and (some might say) more musical. I spent the rest of the week with the Manley electronics, and would recommend them for the Integrum speakers if that kind of sound matches your tastes.
The challenge of speakers as revealing as the Integrums is that they will reveal any upstream issues in your system. Tubes that I thought were noise-free proved not to be so. Inteconnects and speaker cables that I found superb with my reference speakers proved to be less so with the Integrums. This could simply be due to the fact that the speakers were voiced with the Teresonic wire, and using any other cable will take away the magic that these speakers can create. I retubed my system to quieter levels, and continued to marvel at how realistic the music could get. I turn to solo acoustic guitar when I want to get into a meditative space that heals me after a hectic day at work. With the Integrum speakers, it sounded so “live” that it brought visceral excitement into my meditative state.
I wanted to keep these speakers, but my preamp simply had too much gain. Could another preamp take the place of the Companion III? It would be difficult to give up, as it provides musicality and dynamics that are unique in my experience. I should have stopped here, but I took one more step, one that proved to be a big one. To do full justice to these speakers, I felt it was time to do something I'd been putting off for some time—playing vinyl. As Larry would no doubt say, most people who would be interested in this type of speaker would not only have a low-power tube amp but would have a turntable as their primary source. Who was I to disagree? I ordered a VPI Scout turntable, and for the phono stage (and in part to find a suitable replacement for the Companion III preamp), I ordered the latest preamp from Bel Canto, the Pre2P. The journey I was taking with the Teresonic speakers was taking on the proportions of an epic tale, but the move into vinyl sparked by these speakers made the whole saga eminently worthwhile.
To make a very long story short, vinyl proved to be the cornerstone of audio quality, and the best measure of of what I now consider to be one of the finest loudspeakers made. The Bel Canto Pre2P came as close as any solid state preamp has in wooing me away from my tube preamp. In the end, I had to regretfully let both the Pre2P and the Integrums recede into fond memory, though I have a feeling that a pair of Integrums will be in my future at some point. I hope that my tale has inspired you to give these speakers a listen. The manufacturer offers a 30-day trial period with the Integrums, which will allow you to take a journey that will excite your senses, and perhaps give you a glimpse into another way of enjoying music. John Beavers
We were very impressed with the range of equipment John has tested with the Teresonic speakers, and the refined sound he obtained in several different equipment combinations. The CD, Abby Lincoln's That's Him, was stunning in more than one of the setups, showing that many excellent matches can be accomplished. John has certainly pushed the envelope with mid- and high-powered amplifiers, with some great results, and we are wondering if high-gain preamps would be beneficial for low-powered amplifiers such as 4-watt 2A3 tubes. To keep the sonic character unchanged, it is recommended to use Teresonic speaker cables—the same cables used inside the cabinets, although other good matches are certainly possible.