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Teresonic Integrum JL Floorstanding Speaker

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 Teresonic Integrum JL single-driver speaker

A Little Background on Me and Lowther Drivers

My favorite audio writer by far is Art Dudley. I often still think about, and miss Listener magazine. It was he who whet my appetite to hear some Lowther-based speakers. That sounds easier than it is.

At the time I started to read Listener, I lived in Columbus, Georgia and couldn’t find anyone who owned a pair. I knew of no dealers, and there are still very few dealers who stock Lowther-based speaker systems. I have never been into DIY stuff much, because I could really botch kits rated “very easy” to assemble. This seemed to be a downside if you wanted to learn about Lowthers. So finally, I broke down and went to a Stereophile show and set out to find the rooms with speakers that used Lowther drivers. I loved the sound, but the cabinets were huge and I could just hear what my wife would say about them.

I share all this because when I started reviewing, the first thing I asked for was Lowther-based speakers. I thought I would never get them, but this is my third pair to review in the last six months, and I have enjoyed them all. The other point of interest to me is that it seems Art Dudley was very much influenced early on as an audiophile by Lowthers and didn’t come to personally own Quad 57 ESLs until 2006. My audiophile path is almost just the opposite. I cut my teeth on the Quad 57s, and still in my mind’s eye I judge all other speakers by how they compare to them. It would be 2007 before I would have a pair of Lowther drivers pumping music into my listening room.

Well enough of that, it’s time to talk about Lowther loudspeakers. You know, someone needs to answer the question: What has made them continue to be so truly beguiling to audiophiles for nearly 70 years? Lowther was able to combine a low-mass paper cone that uses a incredibly powerful magnet to produce a driver that has a voltage sensitivity around 97dB in free air. Add to that the fact that they have a sensible impedance curve, and all you have to do is provide the appropriate cabinet or horn and you have a speaker that can play very loud and full ranged with an amp as small as two watts.

Lowther started producing hi-fi amplifiers and tuners in England in the early 1930s. They came in a large wooden radio cabinet. What the company quickly became known for though was the partner speaker. A Paul Voigt corner speaker. It was an amazing feat then to get a single, six-inch full-range cone with the addition of a ‘whizzer’ to play out past 13kHz.

Lowther did a lot of work on magnets, and after WWII released the new PM1 driver. It retained the same performance as the original Voigt but was easier to manufacture and use. This was an era of real success for Lowther. By the late 1950s, people began to want stereo and the search was on in most of the world to build smaller loudspeakers. Thank goodness, Lowther has continued to refine and produce their wonderful drivers to this day.

Now, their frequency response is not exactly ruler flat. Surely not what one wanted to see in those graphs they used to run in Stereo Review and Audio. There is good news though: the older the driver the smoother it gets. A new driver will continue to improve, and a freshly repaired one will continue to improve for at least three years, or so says longtime Lowther owners. The longer you listen to a good pair of Lowthers, the more you will be drawn into the music itself.

Lowthers are far from perfect though. Over the years, almost all the successful attempts at Lowther enclosures have been horns or pipes of some design. Most all of these have been rather large, and often not high on the list of wife-pleasing speakers. It is very easy to damage them and very expensive to have them repaired. For another thing, the drivers themselves have certain shortcomings, the likes of which make them unsuitable for less committed hobbyists. This is where the engineers and music lovers at Teresonic come into the picture.

Description & Design Goals

First of all, no one could miss the fact that these speakers have exceptional and beautiful cabinet work. Rosewood veneers cover the front, top, and back while the sides are finished in a high gloss black, and my pair had a beautiful work of art on the side panels: An original work of art portraying Charlie Parker playing his sax. Then, there is layer upon layer of a lacquer made from a very old European recipe that is applied to the cabinet, and then it’s polished beautifully. Everyone that came by thought they were just beautiful, and if you are lucky enough to get one of the Jazz Legend series, you become the proud owner of a one-of-the-kind work of art. You even get the original art work itself and certification if you buy a pair of these.

Teresonic speakers, right down to the varnish, look more like musical instruments than high-end audio speakers. Mike Zivkovic, CEO and co-founder of Teresonic, says that the shape, woods, and even the varnishes are part of the Integrum design. Mentioning Mike, I would be remiss if I did not share with you that Teresonic speakers are designed by good engineers who also have a lifelong love for music and audio. You only have to be with Mike for a little while to know this. He told me that through research and trial and error, they have come to believe that speaker cabinets should be built like musical instruments. They do not believe that speaker cabinets should be built as dead and damped as possible. They feel that a dead cabinet does not produce a natural and alive sound. That is why their enclosures are built by fine musical instrument craftsmen and shaped somewhat like fine musical instruments.

The Integrums are so much more than cabinets, they are a beautiful work of art. They are also a not-so-simple single-driver, crossover-less speaker. They can use either the Lowther DX3 that they come with or be updated to the DX4. The Lowther driver is mounted in what Teresonic calls an Enhanced Tapered Quarter Wave Tube (ETQWT). This special transmission line is a key design priority for Teresonic speakers. They say this is what enables the extremely clean and accurate midrange, the widest range of sound audible to our ears, along with extended low frequency response.

Most of us would probably look at them and think they seem to simply be a Voigt pipe, but there is more in this design than meets the eye. The sides of the cabinets are constructed from ¾ inch MDF. The front, rear, and top of the cabinets are curved and thus are built out of laminated layers of wood that are built up to also be ¾ of an inch thick. There are internal braces placed to achieve the desired cabinet resonances. The Integrum’s quarter-wave pipe is a little over 70″ long, it folds over at the top of the cabinet instead of curving upward like the top-of-the-line Teresonic Ingenium. The Integrum’s pipe opens to the front through an 8.5″ by 2″ rectangular opening near the bottom of the front cabinet.

Mike described it to me as both a quarter wave horn and a transmission line. It definitely has the bass quality I hear from well-designed transmission lines. This design gives extended low-frequency response up to one half-octave below the fundamental resonance of the Lowther driver. The cabinets also employ two filled Helmoltz resonators, which are responsible for correcting the two midrange peaks that are characteristic of all Lowther driver.

The sensitivity of the Integrum speaker is stated to be 101.5dB and this seems very reasonable to me. Even though the manufacturer recommends amplifiers from 3 watts to 100-watt-per-channel, I found they would play at very loud rock and roll levels with only 2.5 watts. Speakers with this kind of sensitivity open up a world of dynamics just not available with low-sensitivity speakers coupled to high-powered amps.

Designing Around The Nature Of The Beast

As most of you know, Lowther drivers can be forward-sounding, or as most often stated, they can have that “Lowther Shout”.

Teresonic attempts to deal with this with the use of Helmholtz resonators which are designed for “picking out” particular frequencies from a complex sound. The resonators are purely acoustical, and responsible for the smooth response of Teresonic speakers without the veiling that notch filters can cause. These filters are based on the work of Herman L. F. von Helmholtz from His book, On the Sensations of Tone, published in 1862. A Helmholtz resonator is a container of air with an open neck, or port. A volume of air in and near the open hole vibrates because of the ‘springiness’ of the air inside. A common example is an empty bottle: the air inside vibrates when you blow across the top. Teresonic loudspeakers use the Helmholtz resonators to both smoothen out the ‘Lowther Shout’ and to boost the low frequency response. My understanding from talking with Mike is that there are two resonators in each Integrum, with a third inside one of them. My ear tells me this works incredibly well after the speakers are broken in.

My pair of drivers came with both the ‘doorknob’ phase plug (what most people call them this because they look like a doorknob), and the bullet phase plug. Each of these phase plugs produce their own unique sound. To me, the doorknob phase plug helps the speakers to disappear, but sounds less coherent. The bullet phase plug is smoother sounding and possibly a little more detailed. One last way of dealing with the Lowther shout is in how you position them. I found they were smoothest when firing almost straight ahead and towed in very, very slightly.

Speaker Setup & Break In

The Teresonic Integrums went right into my system. They were partially broken in, but it still took many, many hours before they passed the mark of daily improvement and reached the optimum. Just don’t forget: Lowther drivers take a long, long time to break in. For most of the time, they were driven by the Wavac EC300B integrated 300B SET amplifier with all Western Electric tubes. Later, I will talk about how they sounded with Teresonic’s own custom built and also special-order 2A3 SET amp. I used both the Shindo Masseto preamp with its built-in Shindo step up transformer and the Vacuum State SVP 1 preamp with its active high-gain phono preamp. The source for vinyl was the Clearaudio Ambient, and later, their Reference Anniversary turntable both with their Satisfy tonearm and the wonderful Micro-Benz TX very-low-output moving-coil cartridge.

I used the Integrums with Audience, Auditorium 23, and Teresonic’s own speaker cables, the Clarison. Teresonic’s Clarison speaker cables are copper-stranded wire that is sheathed in an armor-plated shell to filter out RF and EMI. Reportedly, this is the same wire and shielding that is used in fighter jets. It is also the wire that is used inside the speakers. If I was purchasing speaker cable, I would get the Teresonic wire, it seemed to match the best, but I found all three speaker wires sounded very good with the Integrums.

Like I mentioned above, at first they sounded best aimed straight ahead, but over time I towed them in ever so slightly. They need the supplied spikes to sound their best, but I recommend you wait and put them on after you have found their best positioning. I spent weeks playing with where they sounded best. Some people have found them best nearer the back wall. I tried them there; heck I even tried them in the corners, but in the end they sounded best with the front of the driver three feet from the back wall and two feet from the side walls. I found no need for any special room treatment other then what I use for all speakers in my room.


I want to say right off the bat that the Teresonic Integrum speakers are all about extraordinary transparency with incredible speed at the leading edge. They have dynamics like you can never get from anything but a horn-loaded speaker, and voices that are so clear and palpable that you may think you are there. I’m getting ahead of myself though, so let me backup and get started on how they sound, but you did hear me say they will play seriously loud and really rock, didn’t you?

As I said, I did most of my listening with the Wavac EC300B amp, the Shindo Masseto preamp and vinyl. Always one of the first albums I listen to is Joan Baez’s live recording From Every Stage. The recording quality is excellent, with a nice mixture of instruments to listen to for timbre, there is also the sound of a live recording to listen to, then there is that great voice, but most of all it is just incredible music. The Integrums play this album as good as I have ever heard. Joan’s voice and the band sounded alive, natural, and just plain beautiful.


The midrange is where you have to start with these speakers. As I mentioned above, the Integrums are extremely transparent, immediate, dynamic, and alive sounding. Much of this is from how they get the crucial midrange right. You can compare them to the Quad ESL 57s, the Ikonoklast Model 3s, or the Auditorium 23 Solo Vox speakers; and I think you will come away still thinking the Integrums are just incredibly realistic and beautiful in the midrange. I continue to find speakers with no crossovers to sound so much more like music. A big reason for this is how they sound in the midrange.

There are significant differences in midrange though between these speakers. The Quad ESL 57 and the Ikonoklast are both slightly more laid back and maybe a little more refined-sounding than either of the single-driver speakers. In contrast, the two single-driver speakers I mentioned have a raw aliveness to them that the other two do not have, and I find it absolutely intoxicating. The Integrums are beautifully detailed speakers. In this area they stand up to comparison with great speakers like the Quad 57s and the unbelievably transparent and detailed Audio Note Es. The Integrums are very articulate speakers in the midrange. Voices sound very alive, very articulate, yet very natural at the same time. When listening to Alison Krauss, the Integrum’s ability to recreate the harmony and the interplay of the voices was just beautiful. Pianos, like most instruments, benefit from the coherency of this speaker. They sound powerful and engaging. You can also very clearly hear both the brushes and the sticks as they come in contact with cymbals and drums; they sound so correct and beautiful.

I could go on and on about the midrange, but let me just say when I got the Clearaudio Reference Anniversary turntable and the Benz Ebony TR dialed in with the Integrums, they sounded more alive than I had ever heard a stereo sound, and I wasn’t the only one to think this. Mike came over to hear them and he agreed. What else needs to be said, I just want to listen, pat my feet, and sometimes just get up and get into the music. Isn’t that all you can hope for from the midrange of a great speaker?

The Bass

In my review of the Teresonic Magus I said, “but let’s be honest, Lowther’s don’t have a lot of deep bass. I’ve never heard a Lowther application that went really deep.”

Well, let me tell you I have now. The Integrums really do go down to nearly 30Hz in my room. I can both hear it and measure it. Let me put it this way, when Warren Gregoire, the designer of my WGA Ikonoklast speakers, visited me during the time I was listening to the Integrums, the first thing he said as he just walked in the room while the Integrums were playing was, “they really play deep don’t they.” Incredible midrange is what you expect from Lowther-based speakers, but not deep, powerful, well defined bass like this.

The bass doesn’t just go low; it is quick, tight, and really carries the bass line in the music. Just listen to David Holland’s bass on “Sauerkraut ‘n Solar Energy’, it’s so lifelike on this setup that I get a lot of quick glances in my direction when I play it for people. It has speed, power, and attack that will blow your mind, but that’s not the point. You can follow the musical line so much better than with most speakers, and if you have been listening to digital and boxed speakers, you won’t even believe this kind of bass is possible outside of the live event. As I listened to recording after recording on the Integrums, I realized I had never heard a speaker that produces a more realistic-sounding standup bass. As I tried to figure out why this was, I came up with three conclusions; first, the speed of the Integrums combined with how deep they go; their incredible way of placing the standup bass in its own space; and last, their transparency allows it to sound so lifelike.

Drums sounded equally good. It didn’t matter whether we were listening to jazz, rock, or classical, the tympani and drums sounded lifelike. They also had lifelike dynamics, something you seldom get. They do roll off fast below 30Hz, but I did not find this to detract from their musical sound. I would never think of putting a sub with them, but I know those who would. I just got out Elvis is Back on vinyl and played it. No, they don’t go as deep as the big Wilson’s do when they demo with this music and hugely powerful amps; and no they don’t rattle the room like the Wilson’s. What they do is play just as low using a 2.5 watt amp and have a much more naturalness to the bass. The attack on the drums is quicker and more startling. The difference between the power with which the drums is struck, the early part of the song and the ending climax is much more apparent with the Integrums. I know this is the section on the bass, but I must mention that the real difference is in the voice. If you have not heard this Elvis recording on the Integrums, the Solovoxes, or the Shindo Latours you can’t imagine how they captured the essence of Elvis’ voice on this recording. I have heard no conventional or panel speaker that can do justice to his voice on this record.

If you come to my house to hear speakers, I’ll start you out with Joan Baez, and move on to Miles, Ray Brown, and most definitely Ella and Louie. If my oldest son is home, you’ll get Jimi Hendrix, the Doors, and the Beatles. Then, if you were over at Mikes house, you would hear mostly Classical and some choral. It doesn’t matter a bit with the Teresonic Integrums: You will get bass that sounds like the real thing and goes plenty deep enough to support and emotionally involve you in whichever musical performance you are listening to.

Treble Extension

Just like the Magus, I never thought about the treble of the Integrum one way or the other when I was listening to music, which is the highest compliment I know how to give a speaker. I say that referring to the speaker after they broke in. They were bright for the first few hundred hours, but not in the end; and I don’t think the brightness came from the top-end anyway. I should not say by comparison that the treble might not be as airy or as silky as my Ikonoklast, but I repeat – I only noticed this when I ask myself to listen for it, not ever when I was enjoying the music. The speaker has real presence and has great sparkle. If it misses a little air in the top, I found it hard to hear. Heck, the midrange has so much great air and space if they do lack any in the very top I can’t imagine this ever keeping the speakers from sounding like music.

The real amazing thing is that you can get this kind of treble from an 8-inch driver. As I said, I never thought about the top-end. I sure can’t say that about most speakers I listen to. I’m usually thinking about how the tweeter integrates with the rest of the system, or wishing I could tone it down a little, or I’m blown away by its air and extension. I think part of the wonder of a single-driver speaker that is well executed is exactly that. The bass, midrange, treble, and anything in between all are cut from the same cloth, so you don’t notice the separate parts of the frequency spectrum, and you are free to just listen to the music.

Let me make the point about the top-end one last time. When listening to Opus 3’s Test Record 1, Depth of Image, I thought the sound was beautiful. For example, on cut one, “Tiden Bara Gar”, there was plenty of sparkle and air. The female vocalist sounded as if nothing at all was separating her and her acoustical environment from me. Cut six is an incredible recording of panpipes, and again I could hear all the air around them. Cut seven on side B is a recorder and I have never heard it sound more natural. I know there is no tweeter, but I find the top-end just beautiful to listen to.

Soundstage and Imaging

The Teresonic Integrums and the Lowther America Alerions are quite a contrast in what different people want in a reproduced soundstage. The Alerions have the most spectacular audiophile soundstage I have ever heard. People, instruments, and even the audience sometimes have their own acoustical space. This is true both in side-to-side relationships and front-to-back ones. It is most beguiling and helps make up for what the eyes do when we watch and hear live music. On the other hand, the Teresonic Integrums “soundstage” much more like a real musical performance than a high-end audio system. By this I mean they have a whole, complete soundstage. Just the opposite from what I just described. You get what I refer to as a coherent soundstage. The parts are not separated out, but allowed to be individuals in part of a whole, musical event. Don’t get me wrong, I know how popular the first type of soundstaging is, but most of my favorite speakers (Audio Note, Auditorium 23’s Solovoxes, Shindo’s Latours, and the WGA Ikonoklast) do not do this, but they all give you a wide and deep soundstage that is rock solid; so do the Integrums.

The speakers are so alive and immediate sounding that the questions of imaging and soundstaging just don’t seem to come up when people were listening to them. The reason I say this is not because they lack in these areas, but that they do not depend on soundstage and imaging to sound real. I think often times soundstaging and imaging compensate for an unrealistic sound. So the soundstage makes us feel like at least the images in space are amazing. Let me ask you, have you ever thought about this at a live concert? I know some of you have closed your eyes to see how live music images. I have too, then it dawned on me the insanity of it. I mean when you’re at a live event it is more than an auditory experience, don’t rob yourself. The Integrum give us a very realistic soundstage, but they depend on their musical sound to trick you into thinking you are there. Truth is just like I have often said about my Ikonoklast, they sound as real on a great mono recording as they do with stereo recordings.


As I have said many times before, scale is far more important to me than soundstage and imaging. The Integrums excel in this area. They have the ability to have huge scale when called for and to sound small and precise when they should. They have a wonderful way of allowing you to experience a completely natural sense of scale. No better example could be had of this than the beautifully recorded audiophile old faithful, Cantate Domino. The way the organ surrounds and towers over the choir is so realistic.

The micro-dynamics are what I would expect from a good execution of a Lowther driver; in a word, they are world class. Yes, the Integrums have startling dynamics when the big passages come along, but it may be the micro-dynamics that make it really sound so alive. I always listen to Muddy Waters sing the blues when I am evaluating micro-dynamics. The Teresonic Integrums will stand up to any speaker in this regard, be it an electrostat, a ribbon, or most any other speaker. The way they are with micro-dynamics allows voices to sound very articulate and natural at the same time. It allows plucked strings to sound alive. The micro-dynamics allow you to hear the fingering of guitars, and just listen to Ray Brown play the bass. In my way of thinking, well done micro-dynamics like what the Integrums have is what allows us to really obtain PraT.

The Sound of Strings

To me, strings are a big test for any speaker. The Integrums play strings with speed, life, and air. Like the Shindo Cortese amp, they are just incredible on plucked strings. It didn’t matter whether it was a blues guitar, a standup bass in a jazz group, or a harp, they all sound so natural and so wonderful. You hear the leading edge, fast, quick and dynamic.

For example, one of my favorite recordings is King of the Cellist, Starker plays Kodaly. This is one of the most beautiful recordings of a cello I have ever heard. It can also be insightful to listen to the cuts that are of the cello and the violin. The Integrums let all of the emotion of this performances come through. I find Starker to come across as quite intense, but full of feelings. When listening to this recording over the Integrums I found it very hard to take notes, so involving was the experience. The cello was warm, beautiful, and quick. The Integrums, when paired with the Shindo Masseto and the Wavac EC300B, have that special ability to exhibited a great sense of breath and space not only around the instrument, but within the instrument as well. A lot of the speakers that come in for review can’t pul this off.

They convey this warmth and life without any bass hangover or boomieness. The violin sounded just as good as the cello, very sweet, and never bright or strident. The violin did seem very intense and even aggressive, as it should on this piece. The emotions the Integrums relay, as the bow is slowly pulled across the strings, are very moving. They allow you to hear different layers and textures of the tones of the strings as you hear bow passes over each of them.

Amp #2 Comes To Play & A New Turntable Shows Up

When I went by to pick up the Teresonic Integrums for review from Mike Zivkovic, he asked me to sit down and hear them first. He wanted me to hear what they sounded like when correctly set up.

I was shocked by the sheer volume and scale they were capable of, driven by just 2.5 watts with his custom made 2a3 amp. Then, as I was finishing this review, I had an idea. I called Mike and ask if he could bring the amp over and leave it for a while, so I could comment on how the Integrums sounded with 2.5 watts, as well as the 10 watts I had. So I begin my education about the sound of 2a3 amps. Not only did I get the new amp to hear them with, I also got in Clearaudio’s Anniversary Reference Turntable. The addition of these two into my system made for astounding sound in the bass.

With either amp, the Clearaudio Anniversary brought a degree of focus to the Integrum that was just dead on. With the Teresonic amp and the Anniversary table, the bass had incredible power and slam. The difference between the two amps was interesting enough that I plan to devote an entire review to the Teresonic 2a3 Reference Amplifier.

The new amp did nothing, but confirm my opinion about these wonderful speakers. They are capable of revealing whatever is fed to them. It did show me they could sound a little bigger and more powerful in the bass than I had heard them. Again though, that is the difference in the amps. What I learned from what the Teresonic Reference 2a3s in my room did accomplish (besides all the fun of listening to these great amps) was to confirm what I heard at Mike’s place. The Integrums can really rock and play very loud with just 2.5 watts. So for all you flea amp lovers out there; here is a great speaker for you.


These speakers both met my expectations and surprised me. I expected transparency, tunefulness, speed, and clarity. I didn’t expect such great bass, and I surely didn’t expect them to go down to near 30Hz. It’s not weak bass either. It’s powerful and tight.

Don’t misunderstand me, these speakers are not mostly about the bass. No, they do so much more. They will absolutely make music. The Teresonic Integrums deliver all the single-driver magic I had hoped for without any of the limitations of the other single-driver speakers I have heard.

I didn’t want to go overboard here about how great these speaker are, but it seems I couldn’t help myself. They aren’t perfect, but I do really, really like them. They are natural sounding speakers that really bring music to life. If you find musical truth in single-ended triode amps like I do; speakers like the Teresonics fulfill a real need. Well I’ve said enough. Let me leave you with one thought; the Teresonic Integrums make beautiful music!

Comment From Teresonic:

Teresonic thanks Jack Roberts for his thoroughly enjoyable review of Ingenium Jazz Legends – a limited edition loudspeakers. This article comes after the Innovations award at the CES 2007 and an excellent Art Dudley review of Ingenium in Stereophile. Such great recognition serves as reinforcement to us, the designer and the manufacturer, that goals of many years of development have been met. When Teresonic’s line of loudspeakers was conceived, the main goal was to bring musical reproduction as close to the natural sound as possible. Knowing that goal is achieved is utterly satisfying.

Developing Ingenium Jazz Legends series as Teresonic’s anniversary edition was a unique effort involving acoustical engineers, designers, artists (painters), and cabinet makers handcrafting each and every pair as one-of-a-kind work of art. Thanks again to Jack Roberts and for recognizing that effort in such an excellent review.

Miles Dabic, CTO

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