* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download The MIT Cables, Terminators, and Hoses
Power over Ethernet wikipedia , lookup
Sound recording and reproduction wikipedia , lookup
Fade (audio engineering) wikipedia , lookup
Dynamic range compression wikipedia , lookup
Three-phase electric power wikipedia , lookup
Switched-mode power supply wikipedia , lookup
Buck converter wikipedia , lookup
Loudspeaker enclosure wikipedia , lookup
Sound level meter wikipedia , lookup
Fault tolerance wikipedia , lookup
Alternating current wikipedia , lookup
Loudspeaker wikipedia , lookup
Opto-isolator wikipedia , lookup
Resistive opto-isolator wikipedia , lookup
Ground loop (electricity) wikipedia , lookup
Studio monitor wikipedia , lookup
Sound reinforcement system wikipedia , lookup
Telecommunications engineering wikipedia , lookup
Transmission line loudspeaker wikipedia , lookup
Electrostatic loudspeaker wikipedia , lookup
volume 20 The High End Journal™ issue 103 reprinted with permission The MIT Cables, Terminators, and Hoses AND FRANK DORIS, OH MY! W HEN AUDIOPHILES think of state-ofthe-art, expensive, technologically trickedout cable, the first name that comes to mind is MIT. That’s because of their pioneering efforts in the field of High End cable design, beginning in the late Seventies when Bruce Brisson designed the sonically distinguished Interlink Reference for Monster Cable. Not long after that initial effort, Brisson began the MIT (Music Interface Technologies) company to develop more advanced designs, the first of which, the MH-750 Music Hose speaker cable, rocked the audiophile world, not only because of its appearance (no one had ever seen High End speaker cable the diameter of a garden hose before) and price (the then-astonishing $32 per foot), but also its performance—the MH-750 was sonic leagues beyond all previous speaker cables, especially in its doubled-up (and correspondingly increased price) “Shotgun” configuration. The counterpart MI-330 interconnect soon followed in 1987, and this had, if anything, even more of a dramatic impact on the audiophile community as it simply annihilated all other interconnects, allowing High End systems to attain a then-undreamed-of level of performance. Brisson continued to advance his designs over the years, and was the first to introduce termination boxes into his cables—having invested substantial sums into research and development—but much of MIT’s initial cachet had worn off, since an entire High End cable industry had developed in the wake of their initial Shotgun blast.1 Dozens of manufacturers and designs sprang up to siphon the profits of a now-lucrative market. As in any technological field, the designs ranged from solidly engineered to overpriced mediocrity. This, combined with the audiophile’s tendency to embrace the novel, the cable-of-themonth with the hot buzz (and to confuse a sonic difference with a sonic improvement), resulted in MIT’s audiophile status going from the vanguard to just-another-good-cable, maybe the best, maybe not—although you’d see certain audiophiles and manufacturers (Spectral and Wilson Audio foremost among them) who would insist on using nothing but MIT cable in their systems, year in and year out. As far as my personal reviewing perspective was concerned—I’m known as a person who is open-minded, willing to try anything when it comes to auditioning cable. As a result, I’ve heard designs from (deep breath) A.R.T., Acarian Systems, AudioQuest, Cardas, Cello, CoganHall, Ensemble, Expressive Technologies, FM Acoustics, Finestra Design Group, FMS, Forsell Mediphon, Goldmund, Grado, Kimber Kable, Monster Cable, Music Metre, Nirvana, Music and Sound Imports, OCOS, Siltech, Straight Wire, Magnan, Millennium, Tara Labs, Tice Audio, Transparent Audio, WireWorld, and XLO Electric in (mostly) my system as well as Harry’s, along with various MIT designs. Nevertheless, I hadn’t heard Brisson and company’s latest version of the MH-750 with Terminator, and MI-330 with Terminator, until one day the impulse hit me. The impulse was partially prompted by my having listened to what is perceived as MIT’s direct competition—the Transparent Audio Laboratory cables, a favorite—quite extensively, and didn’t think it was fair to commit a word to print without hearing the latest MIT cables. This proved to be a far more complex task than simply swapping out the cables in my system, breaking them in, and listening. It is a truism, of which experienced reviewers are well aware, that complex system interactions exist between cables, electronics, and speakers—impedance matches/mismatches; considerations of complex impedances and capacitances versus frequency; propagation effects; grounding, shielding, and induced noise and hum; cables acting as antennas or RF coils; connector and interface matches/mismatches—to say nothing of the effects of different geometries, conductors, dielectrics, connectors, and the like. (And you thought us audio reviewers just plopped down in front of a bunch of cool, freely-loaned gear and partied, occasionally getting motivated enough to write a review.) It is also a truism that experienced reviewers think they can get a quick fix on a cable by putting it in and listening, without substituting any of the system’s components to factor out the sound of the cable from the interaction effects. This cuts both ways. On the one hand, one usually can get an idea of a cable’s sound by doing this. On the other hand, the sound of a cable does not exist in and of itself—it de facto must work as part of a system, much as a tube has no sound apart from the circuit in which it is installed. In any case, the MIT cable would not allow such quick and-dirty evaluation, as the following tale will attest. I first installed the full complement of cable— phono and line-level interconnect (the phono interconnect features terminator boxes so heavy I had to weigh down the preamp with a VPI brick), digital interface cable, and a bi-wired set of speaker cable. The first thing that struck me— 1 To this day, I’ve never been told exactly what’s in those termination boxes. But what could it be, besides an impedance-matching/optimizing network? Eye of newt and toe of frog? And while I’m at it, let me complain about those gritty-feeling, metal-on-metal collet connectors on the ends of the interconnects—a curious flaw in such a premium product. Reviews and I use the word “struck” deliberately—was the incredible (and I use that word deliberately, too) transient attack. Fast transient sounds such as the celeste on Lieutenant Kije [LSC-2150], Willie Nelson’s nylon string guitar on Stardust [Columbia JC35305], Milt Jackson’s vibraphone on Bags Meets Wes[Original Jazz Classics OJC234], and certain percussion instruments, had such a realistic initial attack that they did not sound like they were reproduced in the usual sense. Rather, they actually sounded closer to the real thing in their initial sonic signature than a reproduced facsimile! The effect was, literally, startling—to hear a plucked string or struck percussion instrument’s attack sound so lifelike as to make me gasp in amazement. The second sonic amazement was the resolution of detail. Talk about the old cliché of hearing things on the recording you didn’t know were there—on Kraftwerk’s The Mix [EMI Elektrola 1C 568-7 96650-2], a (digital) recording I’ve listened to hundreds of times, what I thought was a synthesizer playing on “The Robots” was revealed to actually be four synths playing in unison, tuned in three different octaves, in four different locations in space! A similar increase in resolution was heard on a few of my reference orchestral recordings—I could hear individual players within string sections to an unprecedented degree. Concurrent with the improved transient and detail resolution was a reduction in the noise floor. The sonic background was cleaner and quieter; noise that I thought was the result of the electronics or record noise turned out not to be. Nevertheless, I had qualms regarding the bass. Although superbly defined harmonically (the sound of bow-on-string on cellos and basses was, again, amazingly close to real life), it sounded rolled off and lean. I wasn’t sure whether this bass was in fact accurate, and that the Transparent MusicWave Ultra I’d been using previously was bloated; or if I was experiencing a negative interaction; or if in fact the MIT cable rolled off in the bass. I didn’t want to believe this last fact, not after hearing the cable in other systems where it sounded right. Time for more experimentation. (Unfortunately, the use of tube amplification was precluded from these experiments, as the cable cannot be used with tube amps. In fact, a former TAS reviewer once fried a pair of Conrad-Johnson Premier Eights….) The next step in the testing was instructive, if unsuccessful. I had taken delivery of the Concentric Speaker Technology Reference Monitor speaker system, and the manufacturer had specifically told me that MIT cable was not a good match for their speakers, so I had to take down the MIT cable. As they came down for the initial setup, I had to switch back to a cable to their liking—in this case, back to Transparent all around. We got the speakers roughed-in, nothing more, as they were equipped with a new pair of too-bright tweeters that required considerable break-in. I also had to use a tube amplifier (a McIntosh MC275 re-issue) on the top end of the system, doubly precluding the use of the MIT. In the course of experimenting with optimizing the system, I naturally installed the MIT cable at one point. You see, it’s one of my few perversities— when a manufacturer recommends that I not try something, my impulse is to try it immediately. The S ound Since I needed another solid-state amp for the test, I brought home the Chord 1200 so highly recommended by REG in Issue 99. I hooked the Levinson 23 on top and used the Chord to power the subwoofers. Well, this sounded horrible. I couldn’t listen for more than one session—the sound was grainy, steely, irritating, lifeless, flat, and completely non-dimensional. I wasted little time reversing the amplifiers, Chord on top, Levinson on the bottom—and this was much better. The sound got its spooky detail and transient capability back, with a huge soundfield extending far beyond the outside edges of the speakers. Still, it wasn’t right—there was a dramatic midbass suckout present that could not be alleviated by any degree of speaker/subwoofer placement, and the lower bass was feeble at best. The midrange also sounded a bit too hard. I put the Transparent cable back in, which brought the bass back, but lost some of that magical resolution and transient response. At this point, I was lost at sea. I didn’t know whether the speakers, the cable, or both were at fault and I spent the rest of the day drinking beer and watching TV in a state of depression. (Note that I was using the Transparent Ultra series, second-from-the-top of their Reference series, and hence didn’t know whether I should send back all the cable in my house and start from scratch with the Reference in the hopes of finally getting everything to click). Sonic salvation came as a result of an accident. A resistor in one of the Concentric speaker crossovers blew (on a weekend in the middle of testing, naturally). This weekend I really wanted to listen to music rather than watch TV in an ethylized funk, so I hauled back in the Alon IIs and bi-wired them with the Chord 1200. Nothing could have prepared me for the result of this combination—the finest sound I have ever experienced in my listening room, by a titanic margin. If I’d thought the Alons were overachievers before, I now realized that, if anything, I’d underestimated them. And that REG was right about the Chord—under the right circumstances, it is a superlative performer. The sound was even more detailed than previously, with no grain or sense of distortion whatsoever. That spectacular transient response was even more so. I could not believe the realism of the triangles and other percussion on Gershwin’s An Ameri can in Paris [RCA LSC-2367], and the vibraphone on Bags and Wes was even more present. (I could almost tell what grade of hardness of rubber mallet Hampton was using.) The soundstage extended a couple of feet more beyond the speakers, and behind, with excellent delineation of recording spaces. (I could now begin to differentiate between the sizes and shapes of halls on various RCA Living Stereos, something I could only get a sense, rather than an accurate picture of, in dozens of other system configurations.) Dynamic contrasts were dramatically improved, as the music breathed more effortlessly. Quiet passages were rendered more cleanly, with less smearing and obscuration, and loud passages hung together more coherently, with less strain. Image dimensionality and specificity were also improved to a degree of excellence of which this writer thought the system incapable, with vocalists and instruments, on a recording which allowed it, achieving that rare, reach-outand-touch-them quality that almost fools the listener into believing actual physical entities are present within the listening environment. The upper midrange and highs were extended without being bright or glary, and remarkably open and uncongested. The midrange was wonderfully lucid, harmonically defined, and tonally neutral—not plump, lean, romantically softened, or harmonically threadbare—simply as right as I have ever heard it in my home. But wait, there’s more, as the Ginsu knife commercials say. In fact, I saved the best for last, and that was the mind-boggling improvement in the bass. Obviously, the previous complaint of lean bass was a system interaction after all, as the Chord/MIT/Alon bass now extended a good halfoctave below any of the many other amp/cable combinations tried in the past. It was also far tighter and better damped with, along with that fantastic transient response (try the electronic kick drum on New Order’s “Blue Monday” [Factory Factus 10]), almost no overhang, excellent image placement (the bass instruments on An American in Paris were never more well-defined, spatially), and, again—I know I keep dwelling on this, but you really do almost have to hear it to believe it—almost unbelievable harmonic definition and accuracy. You will not believe what this cable does to well-recorded jazz trio LPs such as Bill Evans at Town Hall Volume One [Verve V68683] or, for that matter, large-ensemble recordings such as the sensational new Duke Ellington tribute CD, Mr. Gentle, Mr. Cool, by David “Fathead” Newman [Kokopelli KOKO 1300]. Even synthesizer recordings take on new-found musical credibility. After all, when one hears more of what was on the master tape, one gets a stronger emotional connection to the artist’s original intent, simply because one can hear more of it! All these sonic improvements, regardless of how impressive, would mean nothing if the overall sonic gestalt were not convincing. We’ve all heard systems that did most things right but still left us cold, as the various parts of the musical fabric were audibly disconnected. Not so with the MIT CVT with Terminator series, which, when working in the right system (as it was in my final testing incarnation), affords a remarkably convincing illusion of musical reality. So many things are done right—tonal balance, staging, imaging, dynamics, resolution—with such a lack of perceived distortion, that it enables one to be effortlessly drawn into the music, rather than focus on obvious flaws. (Ever notice that, paradoxically, when a system does many things right, one focuses all the more on what’s left that’s wrong— more so than if one were listening to a sonically less-distinguished but better balanced system? These days, I look forward to hearing my stereo with delightful anticipation, something I haven’t been able to say since, well, 1992. You may have to struggle to get your system to optimally synergize with the MIT cable—in fact, it’s a strong possibility—but if you can get your system to sing as I did mine, you will be rewarded by a level of performance and a level of emotional involvement with the music you probably thought impossible. I know I did. —FD Reviews Manufacturer: MIT (Music Interface Technologies) 3037 Grass Valley Highway Auburn, California 90232 916.888.0394 Bruce Brisson Manufacturer loan n/a MI-330 CVT Plus Terminator interconnect: $1,800 per meter pair; MI-330 Plus Terminator phono interconnect: $2,200; MH-750 Plus Terminator speaker cable: $4,500 per 8-foot pair; Terminator 3 Digital Interface cable: $99.95 Warranty: One year Designer: Source: Serial Number: Price: FD’S ASSOCIATED EQUIPMENT Front End (digital): Philips CD-80 CD player (used as transport), Theta Data Basic transport; Theta Cobalt 307, Theta DSPro Basic, Audio Alchemy DACIn-The-Box D/A converters Front End (analogue): Sumiko Blue Point Special cartridge; Well Tempered arm with Sumiko Analogue Survival Kit arm wrap; Goldmund Studio turntable Electronics: Audible Illusions Modulus 3 preamplifier (tested with Amperex 6922, Amperex 6DJ8 “Bugle Boys,” and Sovtek 6922 tubes); Mark Levinson No. 23, Chord 1200 amplifiers Speakers: Acarian Systems Alon II, Concentric Speaker Technology Reference Monitor System with subwoofers Manufacturer’s Response: I want to thank Frank for the thorough manner in which he reviewed the MH-750 CVT Plus Terminator and MI-330 CVT Plus Terminator interfaces. When changing cables, certain things didn’t add up in Frank’s mind—things that seemed confusing and unpredictable. Concerned for the manufacturer and for the accuracy of the information he would ultimately deliver to TAS readers, Frank took the time to get to the bottom of the issue and didn’t give up until his system sounded correct and he was sure he had the right answers. HP says TAS is on the way back; could this type of reviewing be just the beginning of something new? Over the years many reviewers have asked how a cable interfacing two pieces of equipment The So und in a system could possibly change that system’s tonality and imaging characteristics to the large degree they hear. How can this happen; does it make sense? Picking up where Frank left off, I would like to try to shed additional light on this complex subject. Reviewing in a linear system: The words “linear” and “predictable” can be interchanged, as can “non-linear” and “unpredictable.” A linear system, then, is one that we can predict will behave in a certain way under controlled circumstances. A linear audio system makes minimal changes to the characteristics of the source from the output of that source to the end—the sound coming out of the speakers. With such a system, we can judge the behavior of a new component on an even playing field. We can say, when we hear the changes it makes in our linear system, that we are confident that the new component made the change, rather than some synergistic interaction that we don’t know about. In order for a system to be linear, however, every component in it must be linear. You can’t correct the non-linearities in one component by adding the non-linearities of another. Two wrongs don’t make a right! In my experience, systems that take you by surprise and overwhelm you with unpredictable results possess one or more non-linear components. That is, something in the system is making unacceptable changes to the music signal. Remove the non-linearity completely, and you will have a better system. Touch or tickle the non-linearity, and you will modify or change it, maybe move it around. Feed or enhance the non-linearity, and you will just make the situation worse. Reviewing can be seen as a form of test, with the measurement provided through the reviewer’s ears. Engineers use test equipment, not their ears, to provide measured data for interpretation. In the first instance, the interpretation of the system must satisfy the criteria of the reviewer’s ears. In the second, interpretation of the measured data must satisfy the engineer’s model. Today, our industry really requires both tests, because neither alone tells the whole story. Today, test-bench measurements characterizing the non-linear activity of a device, using a linear test architecture, are common. However, even the best test and measurement engineers have difficulty measuring non-linear distortions in a non-linear system. Often, this form of measurement is impossible. So, if engineers cannot measure non-linear distortions within a non-linear system, pity the poor reviewer who must review a single piece of equipment in a non-linear system! How can he or she know what is affecting what in this type of system? Frank has done a superb job of sorting through his system’s non-linearities and changing the test system’s architecture to get his answers. As anyone in this business knows, this can be a dizzying and draining experience. Let’s look for a moment at how the audio system works. First, what constitutes a system? In general, a system is a combination of interconnected components performing a specific function. A system usually has two or more inputs and outputs interconnected so that the output of one component serves as the input to another. Home audio sys- tems consist of a number of components connected in series: CD player to preamplifier to amplifier to loudspeakers. A system is characterized by its inputs, its outputs (or responses), and the laws of operation adequate to describe that system. In electrical systems, the laws of operation are the familiar voltage-current relationships for the resistors, capacitors, inductors, transformers, transistors, etc. Using these laws, we can derive mathematical equations relating the outputs to the inputs. Second, let’s define a musical signal in elec trical terms: In its acoustic state, we perceive music as a difference in acoustic pressure. For example, the human vocal mechanism produces speech by creating fluctuations in acoustic pressure. By using a microphone to sense variations in acoustic pressure, we convert these varying acoustic pressures into an electrical signal—voltages and currents. A speaker senses varying electrical voltages and currents, and converts the signals back to their acoustical state. In its electrical state, a music signal is comprised of voltages and currents. These have electric and magnetic fields and fluxes associated with them. These fields and fluxes store energy (or charge) and discharge energy. This energy can provide work or power. These fields and fluxes also constitute the state of the component part. If we evaluate the energy storage and discharge of capacitors and inductors in time, we will know the input-output state of that capacitor or inductor at any given instant. Understanding passive components: Capacitors, inductors, and resistors are called passive components because they provide no volume gain, as a transistor or tube does. But they do something else. Simply put, a capacitor stores voltage in its electrostatic field, and an inductor stores current in its magnetic field. Because pure capacitance and inductance store voltages and currents for 90 degrees and then return them back to the circuit or network, these components can be said to have a “memory.” A pure resistance has no memory, for it does not store voltage or current. Instead, it consumes them as power and turns them into heat. This is the way it happens in the ideal or linear world. However, these pure—and linear—components exist only in the ideal world of mathematics. In the real world, such as our audio systems, the behavior is more complicated. Capacitors and linearity: Like a system, a component part can be linear or non-linear. A passive component’s ability to charge and discharge is directly related to its linearity. A capacitor has a value expressed in Farads, and a phase angle or time relationship expressed as –90 degrees. Remember that a capacitor has a memory related to voltage. Because of this, its voltage lags its current by a phase angle of 90 degrees. The linear capacitor will retain its value and phase angle to a varying voltage level. (A capacitor’s value and voltage are usually given in its specifications, so that the designer knows the behavior to expect from this component part.) In addition, the linear capacitor will not be time varying. That is, it will retain its value and phase angle over a specified range of frequencies. (Richard Marsh, one of MIT’s engineers, exposed the problem of capacitor performance to the Reviews audio community in 1980 in a two-part cover article in Audio magazine. He showed how different dielectrics respond to this type of criteria over different audio frequencies.) Inductance and linearity: An inductor has a value expressed in Henries and a phase angle of +90 degrees. An inductor has a memory related to current, because it stores current in its field for 90 degrees. This means the inductor’s voltage leads the current by 90 degrees. A linear inductor will retain its value and phase angle to a varying current level. (An inductor’s value and amperage are usually given in its specs.) The linear inductor, like the linear capacitor, will not be time varying; it will retain its value and phase angle over a specified range of frequencies. Non-linearity in circuits with both capacitance and inductance: In audio systems, capacitors and inductors do not behave ideally. In the real world, they are always to some degree non-linear at some frequency, at some level of voltage or current. And this affects the sound of our systems. Remember that the stored energy in the memory of inductors and capacitors is music information, translated, as we have said, into voltages and currents. When these two elements are returned to the circuit in phase—in the proper time relationship—they add together optimally, and aid each other linearly and predictably. The music is therefore reproduced properly. If the voltage and current are not in phase, however, the current and voltage fields won’t add together to aid each other. Instead they add together un predictably, and some degree of non-linear activity takes place. How can we know what this will sound like? We can’t. This behavior is unpredictable. Understanding cable functioning: A cable has capacitance, inductance, and resistance. Its inductance comes from the coiled wires in its construction. The positive and negative sides of the cable form the parallel plates of a capacitor. Resistance is part of the total opposition to the alternating current in a circuit. If we recall once more that music signals traveling through an audio system are nothing more than voltages and currents, we can understand that a cable interfacing components in a stereo system will charge—that is, store—the music signal in its capacitive and inductive fields. The resistive elements in the cable, if linear, will “consume” part of the music and turn it into heat (power). If nonlinear, however, the resistive elements will generate noise to some degree. Most of today’s High End cables generate more noise from these elements than they consume as power. The fields of inductors and capacitors, once charged, contain energy. We at MIT refer to these fields as “the Energy Components.” Because the music signal is stored and transported within the fields of a cable’s capacitive and inductive elements, and the resistive elements can create noise, the linearity of these three elements directly affects the sound of the system the cables are interfacing. A pure capacitance or inductance has a memory lasting 90 degrees, as I stated earlier. A speaker cable, as an example, charges and discharges its capacitive and inductive field twice each, for a total of four times, per Hertz. The en- The So und ergy, when returned in phase (that is, in the proper time relationships) back to the circuit, is then converted to power at the speaker. The energy that is not returned in phase is either consumed by the resistance of the cable, or exchanged for power at the load (speaker) at the wrong time. In a stereo system, this out of phase energy can change the tonality of that system and affect its imaging ability. Sonic behavior of cables: With this general knowledge of passive electronic component behavior, you can begin to listen to cables with a better understanding of why they do what they do. To give you a general idea of how these distortion mechanisms manifest themselves sonically, let me list a few of the more common ones I continually encounter. Most cables fail at the frequency extremes of audio. They tend to have difficulties transporting low signal levels or high signal levels at one or both frequency extremes. Most cables function properly only when transporting moderate signal levels, and only in the middle octaves. Low signal levels are accompanied by a form of uncertainty, which manifests itself as a form of analogue jitter, forming a noise component in the lower octaves. If we stretch things, we can say this distortion is similar to the more familiar digital jitter. Because of this uncorrelated jitter or noise, most cables won’t image in the lower frequencies, particularly when played at low-tomoderate listening levels. This is because the uncorrelated jitter or noise causes the left and right speaker to move out of synchrony—not together, but to a different beat, so to speak. Most cables fail to transport in-phase energy in the lower audio octaves, particularly at low signal levels. Some are level sensitive and will pass in-phase power only at high signal levels. Because of this level sensitivity, some of these cables must be played at very loud levels to extract any realistic bass weight. Turn the volume down—and the bass goes away! At the other extreme, some cables inject noise or instabilities into the high frequencies, usually in the last octave or two, particularly highlevel signals. Cables exhibiting a mild form of this distortion will sound all right at moderate listening levels in the high frequencies, but in loud passages, the image stretches vertically in the last octave or two. These cables may also bloat the image in the affected octaves, pushing it well out into the room, while seeming to push the low frequencies to the rear of the speakers. In the worst cases, these cables can take on a hard and harsh sound, particularly on the leading edge of the transient. Distortion and the reviewer: These distortion mechanisms and resulting sonic manifestations are an obvious problem for all reviewers. How can they start to sort things out? How can they determine what is causing the tweeters to roll off, for example, when they change the cable? Was it because the speaker was designed with a cable that added a noise component or instability at those frequencies? Is the new cable faulty? Or is it instead properly engineered, while the discernible roll-off is the result of a resistor the designer put into the crossover network to attenuate the tweeter to match the non-linear cable he/she designed with? (My favorite gripe: Nonlinear inductors used in the woofer section of many speakers. If you cannot predict the phase angle of the inductor to a given current, you cannot predict the bass output of the woofer.) In Sum: I stated earlier that measuring nonlinear activity in a linear test architecture is possible—and common—while measuring non-linear distortions in a non-linear system can be impossible. A High End reviewer today, “measuring” with his ears, is up against the same set of problems engineers are faced with. A reviewer, for example, can easily evaluate a cable installed in a linear system, one whose source and load are linear. But the same reviewer will be hard pressed to evaluate that cable in a non-linear system, one whose source or load is not linear. The best of today’s High End products are extremely revealing. They are capable of revealing the linear—the faithful rendition of the source and system—or the non-linearities of a mismatched system. In our industry, our common goal today is surely to assemble and listen to a linear system, because as Frank put it, “It affords an illusion of musical reality which is remarkably convincing. So many things are done right—tonal balance, staging, imaging, dynamics, resolution—with such a lack of perceived distortion, that it enables one to be effortlessly drawn into the music, rather than focus on obvious flaws.” Frank’s statements are the (predictable!) results you would expect with a linear cable interfacing a linear system. Congratulations, Frank, your hard work and ability to recognize non-linear system interactions have provided a major step forward in audio reviewing. —Bruce A. Brisson MIT, Music Interface Technologies This review has been reprinted in its entirety from The Absolute Sound, with not one word censored or deleted. The Absolute Sound is the journal of High End audio and reports its findings on audio equipment and recordings without fear of or favor from any commercial interests. Its literate evaluations and tests take place in real space, hence, music (the absolute sound) is the measure of reference. Subscriptions may be obtained from this business office at a very special yearly rate of $54.95 including shipping & handling. You may call us directly with your Amex, Visa, or MasterCard in hand at 516-676-2830 or mail your check to The Absolute Sound, P.O. Box 360, Sea Cliff, New York 11579. MIT® products are manufactured and sold by CVTL, Inc. 4130 Citrus Ave, #9 Rocklin, CA 95677 Phone: 916-625-0129 Fax: 916-625-0149