Acoustic Zen technical publications

Should the Acoustic Zen Crescendo MkII be your last speaker?

The world of high-end loudspeakers can be a maddening and sometimes rocky place to traverse. Many audiophiles continuously search for a speaker that will satisfy their needs only to continuously discover that over time, a speaker may become fatiguing, uninteresting, or simply intolerable to listen to. Unfortunately, this can also come with a heavy price tag, even up to the six figure range. So, what if you could find a loudspeaker that actually fulfilled the high-end promise of smooth, full range frequency response, time and phase alignment that creates superb images in space, with vanishingly low distortion and gorgeous finishes all at a price that is within the reach of most music lovers? That loudspeaker is here today!

The Acoustic Zen Crescendo has been received at shows around the country, on dealer floors, and in our customers' homes by audiophiles, reviewers and pundits with incredible acclaim. In its new MkII version, those accolades are even greater. But, how do we get such exceptional sound quality in the first place? The answer is in a design that utilizes solid technologies and techniques that serve the musical waveform first and foremost. Let's face it, there are lots of high quality loudspeaker designs in the high-end, so what exactly makes the Crescendo different from the rest of that packed landscape?

First and foremost, the Crescendo was designed for music and with real, live music as the reference. The reality is that most audiophiles and music lovers spend time with their systems listening to music, not thunderstorms or train whistles. Musical signals are highly complex and reproducing them effectively is not necessarily as easy as it may seem. But, with properly utilized technology, design principals and exhaustive testing it is possible to create a transducer that is faithful to the musical signal. The Crescendo accomplishes full range response along with low distortion, dynamic impact, coherence, efficiency, and realistic imaging.

The drivers utilized in a quality speaker design are its heart and most important component. To ensure a solid foundation we have consistently utilized "under-hung" driver technology in our designs. The principal of the under-hung driver is that the voice-coil is narrower than most conventional drivers' voice-coil and essentially never leaves the magnetic gap of the motor assembly. Basically, the voice-coil is shorter than the magnet's gap or "under-hung". The vast majority of speakers utilize the opposite or "over-hung" drivers where the voice coil easily travels beyond the magnetic gap of the magnet assembly because it is longer than the magnet's actual gap. Think about when you were back in junior-high science; remember playing with magnets? Specifically, the demonstration where you took a bar magnet and placed it under a sheet of white paper and sprinkled some iron filings on top of the paper. When the filings were in close proximity to the magnet, they were more orderly and you could make out the magnetic lines of flux and the further away from the magnet the iron filings were the more disorderly they became. The principal of an under-hung driver is much the same. Since the driver's coil is always inside of the magnetic gap of the speaker's motor assembly, it's under the influence of the magnet across its entire range and it's response has less distortion, kind of like the bar magnet experiment. With over-hung drivers, the coil travels beyond the magnetic gap and causes distortion in its movements, much like the iron filings that are too far away from the influence of a magnet. The advantage to the under-hung driver is vastly lower distortion since the coil is always under the influence of the magnetic gap and how it is influenced by the incoming signal voltage. That being the case, why don't more manufacturers utilize under-hung driver technology to achieve lower distortion designs? Well, there are a couple of reasons; one is expense and the other is that over-hung drivers are easier to work with. Essentially, with a conventional, over-hung driver the tolerances and materials do not have to be as rigid and any anomalies in the response and distortion properties can usually be ameliorated with crossover tweaks and cabinet construction techniques. With under-hung drivers, the expense is greater and the need for very careful matching of components and materials is critical, but the outcome more than compensates for the diligence required in their use. That's why the Crescendo's mid-bass and bass drivers are all under-hung designs to gain the lowest possible levels of distortion and pass the benefits to the listener. And, in the new MkII, our drivers now feature larger magnet assemblies and we've improved the coil to gap ratios due to improved manufacturing capabilities enabling even lower distortion and consequently, greater fidelity!

As you look at the front of the Crescendo, you will see that the upper drivers are in a "D'Appolito MTM" configuration. This allows the best possible recreation of the original waveform and eliminates the "lobing" effect common with other configurations. The advantage to this is that the audio signal will reach the listener in proper phase and time relationships with no smearing due to the signal interactions inherent in conventional designs.

Two five inch mid/bass drivers that employ a unique magnesium alloy impregnated paper cone material flank a horn loaded ribbon tweeter specifically designed and manufactured for the Crescendo. This MTM array asures smooth frequency response with proper phase and time relationships intact and the ribbon tweeter is implemented to provide extended, open, and non-fatiguing response. An aluminum ribbon covers 95% of the vibrating area of the tweeter membrane.

Traditional design
Traditional driver placement
MTM design
D'Appolito MTM driver placement
This unique feature provides a purely resistive impedance which means a friendly load for the amplifier and simplifies crossover design. The vibrating element is almost completely weightless compared to traditional dome type tweeters. This affords immediate and precise high-end response to transients in the musical signal and reveals the dynamics of instruments with high frequency specrtral content like no other. It has an essentially linear phase response which provides time coherent reproduction resulting in accurate frequency response, rhythmic drive and outstanding imaging capability. Our tweeter is quick, without distortion and without ringing. Many modern "audiophile" speakers seem to have tilted up or bright treble response which lends a bit of excitement to the sound, but long term causes listener fatigue and dissatisfaction with the overall tonal balance of the speaker. The Crescendo's mid to high end response is natural, non-fatiguing and remains faithful to the source.

To convey deep bass with resolution and authority, dual eight inch, ceramic coated, underhung drivers are transmission line loaded to extend response to a true 20 Hz. A properly tuned and damped transmission line has the ability to extend bass response without making it "lumpy" or creating a "one-note" characteristic. The Crescendo's exceptional bass response is due to its unique ability to utilize this loading technique to not only give tuneful, taut and deep bass response, but bass response that is in phase at the listening position to complement the proper time and phase relationships inherit in the rest of the design. The musical outcome is startling and can be immediately discerned with fast, coherent and powerful bass that lays a musical foundation for the music. Have a look at the frequency response sweep to the left and you'll see that the Cescendo's effective response is extremely linear and coherent across the audio passband with less than 3db of deviation from frequency to frequency, even at the acoutical crossover point between the transmission line port and the other drivers. Transmission line loading is not the easiest to implement, but it eliminates the "chuffing" and potential phase anomolies of ported designs and the power inneficiencies of acoustic suspension style cabinets. While our bass loading design is more complicated and more costly than most, it affords the truest response to the music, and that makes the extra work to implement it worthwhile.

Proper phase relationships are vitally important to speaker performance and its ability to reproduce a uniform, and musically correct output. Think of this example; If you held a few marbles in your hand that were uniform in weight and size, and dropped them to the floor with the intent of them all hitting at once to produce a single "crack", they would actually all hit at different times and effectively "smear" the sounds your ear perceives since the sounds from the marbles would be striking the floor at different times and all react in different ways in the environment. They would hit the floor "out of phase" with each other. Now, let's take those same marbles and drop them so that they all hit the floor uniformly and in perfect unison. If that is achieved, you will hear one coherent sound. They are now, "in phase". This is a very simplistic example, but the end results are what's important to understand; multiple incoherent sounds that smear what you want to acheive, or one uniform sound. Now, all speakers have some level of deviation in phase as amplitude and frequency change. This also affects the speakers load presented to the amplifier, but the ideal is to get the waveform to launch "in phase" with the signal at the input terminals and to keep from "smearing" that signal. We invite you to do some investigation of competitive products phase response and amplitude curves to see the surprising differences in some designs (some of which are in the upper echelon of high-end speakers in terms of their acceptance and their price!) In the Crescendo, that musical waveform is always produced in phase with the electrical input to the speaker with very little deviation and with a very stable impedance. The result is an output that is true to the input signal and simply outperforms others in terms of sheer musicality, listenability, coherence and accuracy.

The Crescendo employs a crossover network that is so highly refined in controlling the balance of the drivers that it yields a nominal efficiency of 90dB SPL @ 1 meter. The overall design keeps the impedance of the speaker a nominal 6 ohms with no drastic shifts in phase and an easy load for almost any quality amplifier across the audio spectrum. So, while it will certainly respond to and fully complement powerful solid state amplifiers, it will also respond just as well with lower powered vacuum tube designs or high quality integrated amps. This is accomplished while maintaining unparalleled phase and time alignment, smooth frequency response and the lowest possible levels of distortion from the ultra-linear, under-hung driver design. The importance of both proper phase response and smooth impedance cannot be stressed enough; either one, improperly handled, can be the downfall of many competing loudspeaker designs. The Crescendo, however endeavors to ensure that both are high priorities. Proper phase relationships throughout the design ensure that music reaches you intact, as a whole, as it was intended. An impedance that stays smooth and with no wild swings across the frequency spectrum means your amplifier doesn't have to struggle to reproduce the full spectrum of sound that you expect. Couple these with the ultra low distortion and linearity of the Crescendo's drivers and you have a transducer that transcends all of the science, all of the engineering and all of the technology that we've put into it. The Crescendo will respond to what it's driven with and consistently provide a musical experience like none other. Smooth response across the entire musical spectrum. Bass fundamentals that are deep, truthful, taut, and underpin the music as they should. Dynamics, truth of timbre, and imaging that are real and uncolored with an overall sound that is true to the source and non-fatiguing.

In its new MkII version, we have also made improvements to the cabinet and its bracing to lower resonances and overall distortion. As with all Acoustic Zen products, you'll continue to see an unparalleled level of fit and finish and some of the most beautiful cabinet works in the industry. People marvel at the quality of finishes on the Crescendo with its real wood veneers and deep, multi-coat clear finish. The Crescendo will look as good in your home as it sounds and comes in a number of finish choices to complement your d├ęcor. We ensure that the Crescendo is as beautiful to behold as it is to listen to!

Crescendo Finishes

All of this comes at a price that you may not believe. Most would expect a loudspeker with this level of refinement and technology to cost well into the five figure range, well above twenty, thirty, even forty thousand dollars. Instead, the new Crescendo MkII gives all of this performance for only $18,000. Many music lovers and audiophiles have already discovered the tremedous value of the Crescendo and replaced competing designs with price tags well beyond its own price. Most comment that they have searched for years for a loudspeaker with the musical performance of the Crescendo only to be disappointed time after time. The Crescendo has become a "final purchase" for many listeners. You may ask how we're able to sell this level of quality and execution at this kind of a price, especially in light of the competition in the audio world. Let's just say that we believe in selling a great product that can improve people's enjoyment of music and movies at a price that is honest and in line with that product's intrinsic value, not in line with hype, cachet or marketing spin.

Does all of this technology and engineering deliver the goods? Considering our own testing and the comments of numerous reviewers and discerning audiophiles, the answer to that is a resounding, "Yes, and then some!!!". The Crescendo's design goal of faithfully reproducing the musical event has been completely realized. Musical integrity is kept intact with less distortion and greater fidelity across the audio passband than with most competing designs. The Crescendo creates a magnificent image with weight, authority, dynamics, warmth and coherence. And, unlike most of the current full range, high-end loudspeaker designs on the market which command enormous prices, the Crescendo is rationally priced. Crescendo owners are commenting that the Crescendo is the loudspeaker that has ended their quest for the best in musical reprooduction, even after spending thousands more over the years on competing designs. The Crescendo is the obvious choice for the music lover looking for the ultimate in performance and value and could very well be your last loudspeaker. Don't believe us? We invite you to listen for yourself and experience the difference!

Acoustic Zen Technologies Overview

Acoustic Zen's founder and chief engineer, Robert Lee, is among a small but elite group of innovative cable-design researchers. His three-plus decades of pace-setting work has brought him to a scientific understanding of materials and design structures. Lee views cables as inherently musical instruments.

Cables often function as "tone controls," as many people in the audiophile press insist. But Lee views cables as integral to audio networks. Cables are intrinsic to the structure of recording networks and of reproduction (stereo and surround sound) networks, as well. Without cables, no music.

Comprehending the complex nature of the integration between cables and sound systems has been one of Lee's primary research objectives.

Robert Lee's goal, as a research engineer, is to understand the material and design properties of low-level signal transmission. His aim is to create the most accurate possible delivery of musical information. Lee believes that sonic accuracy is innately musical.

In his research work, Lee has pursued variables that determine the signal-delivery characteristics of cables. Five variables in cable design are fundamental: the choice of materials; the internal structure of materials; their amenability to design configurations; cable and network (or system) interaction; and the "bundling" of first order sonic signals alongside associated, internal cable reflections.

Lee's first Acoustic Zen White Paper outlines a number of insights and technical outcomes that follow from his research to frame his evolving design philosophy.

As an independent research consultant extraordinaire across twenty five years on three continents, Robert Lee, created advanced cable designs for several high-profile audiophile cable manufacturers.

In 1998, Lee launched Harmonic Technology, a cable manufacturer that quickly shot toward the head of the pack, earning inclusion in STEREOPHILE's coveted "recommended components."

With the inauguration of Acoustic Zen Technologies, Lee brings his design-knowledge to the creation of an innovative, state-of-the-art series of fine-tunable cables and power cords.

Lee's training as a pianist and a violinist has consistently played a role in his cable-design work. His objective at an early professional age was to create the most musically accurate, sonically-glorious audio components possible within 'real world' retail prices. That ambition to enlarge and enhance the sonic envelope without exaggerated price tags has been constant. Lee's first audiophile product was a self-assembled [DIY] Mosfet amplifier for an overseas market. Lee's aim was to create, at minimum cost, a maximum of class A amplification neutrality and power.

His now classic "True Image" amplifier received critical praise from discerning listeners such as Dick Olsher. It remains, twenty years beyond its first appearance, among the most tube-like solid state amplifiers ever made. Soon after, Lee's "Hologram" speakers amazed dozens of reviewers because of their unrivaled seamless coherence across the sonic spectrum, achieving what many speaker manufacturers have long sought: invisibility and an utterly convincing depiction of music in space.

"I always wanted to create a full-scale concert hall in my listening room," Lee asserts, "and that's what I want to help Acoustic Zen customers build, too."

To that end, Acoustic Zen cables extend the range of sonic accuracy and dynamic impact. They are as tonally perfect as analog and digital interconnects can be at present. Each Acoustic Zen cable is assembled by hand. Each pair is aurally inspected, listened to carefully and critically before it goes out into the world. Acoustic Zen cables are handcrafted to be state of the art instruments for the delivery of music.

"Cable design is an art," Lee believes. "Cables are the physical pathways that deliver music to each of us. There is no other way to make music come alive in the absence of an on stage live concert performance. Each music lover is completely dependent upon cables, many feet of interconnect and speaker cables, in order to hear what a musician works hard to perfect. Cables are also pathways for extremely spiritual events since music, especially great and beautiful music, is spiritual ...something beyond wood and metal, flesh and bone. Therefore, my job - as a musician, as a cable designer, as a lover of great sound and magnificent music - is to create works of cable art that deliver the delicate signals we know as music!"

Lee's objective is to reward the critical listener with "cable art." He declares himself to be an objectivist who is also subjective in his craftsmanship. "I must be very precise in my work because I am an engineer. But I am a romantic, too, because I believe in the power of art to give technology a soul. I named my cable and sound research company ACOUSTIC ZEN because it names my own musical and design values.

"Music at its best," Lee continues, "has an indefinable character of soulfulness ...I call it 'sound afloat.' When music is right, when it is perfect, it seems to soar and dart like children playing on a big, green, open lawn. Music takes you with it. Music gathers us inside itself. It changes our lives. Great music makes us high on nothing but itself. It lets us be as elevated as we truly are, at our best, inside our souls. And so I think that the most perfect music is like zen. And the most beautiful and accurate sound is like acoustic zen.

"That is my belief," Lee insists, "and this is my objective as a romantically-inspired and hard-headed engineer: to be a partner for anyone who deeply loves music. I want to help people experience a sense of inner height and personal enlightenment. I know that seems eccentric because everything in our world is number-oriented. Nevertheless, I want to do my work, which I believe is a form of art, for people who know how to let my cables move them closer to the truth of music's mysterious happiness."

On The Design and Fine-Tuning of Audio Cable

Among the audiophile community, few topics elicit more discussion and debate than differences in interconnects and speaker cables. The reason for this interest and disagreement is easy to understand.

Only in the 1990s, after decades of "high-end audio" growth, did sustained attention focus on the inconspicuous but wholly important role that interconnect wires and speaker cables play in the transmission and enjoyment of music. Only the most complete audio cynic today believes that speaker cables and interconnect wiring is insignificant or irrelevant. Anyone with good ears can hear, first hand, how system-dependent are most cables that operate in a stereo or surround sound system. Even a fledgling audiophile can discern differences in audio presentation constructed from various cable designs, materials and wiring networks.

For several years, before I created Acoustic Zen Technologies, I explored the use of pure, continuous cast "single-crystal" wire. Research into its superior signal integrity and transmission characteristics convinced me of its benefit for digital and analog interconnect cables. Subsequently I have moved to exclusive use of "zero crystal" (extremely long-grained) pure and unextruded, continuous-cast wire. Pragmatic experience as well as theoretical research led me to some-what unconventional cable design techniques, cable structures that maximize coherent signal delivery.

The purpose of any interconnect or speaker cable is to deliver the most absolutely coherent musical signal possible. That goal is more complex than it may appear.

Musical signals are combinations of interacting and overlapping signal frequencies at varying levels of magnitude. Such rising and falling acoustical dynamics contain phase-based information as well as low-level harmonic "strands" or sonic "fabrics" that are fragile and easy to deform. These minute signals can be blurred and, in the time and space through which musical energy travels among pieces of audio equipment, obscured, degraded or, worse, obliterated utterly.

The notion of "obliteration" here points to an important feature of the work that cables carry out. Cables literally "read" and transfer delicate musical signals that flow through them with an almost infinite variety of electronic characteristics. Each cable design, each set of cable materials, interprets the signals it delivers. Cables are not like plumbing. They are not tubes that allow music to pour like water through hollow cavities. Acoustic cables receive, interpret, and discharge extremely small amounts of precisely aligned musical energy. Because this temporal sequence is "music itself," existing as a flowing bundle of minute electrical signals in motion within acoustic cables, it is obvious why cable design and cable material is important. Cables capture music at the point of recording. Cables carry and dispense recorded music in mono, stereo and surround sound reproduction.

Cables, in brief, are at the heart of the musical experience. They sit at the core of the music-making enterprise. In a very concrete sense, cables and the wires that deliver sound shape the image of music from beginning to end.

Music is not only a set of organized sounds moving through air in ambient space. Music is a network of infinitely braided micro-level sonic energy that carries highly-refined and extraordinarily delicate signals that contain vast amounts of acoustic and electronic information. And there is the perplexity of the work that cables do. They must "read" minute electrical patterns that are subject to alteration in delivery as if those signals were the original and subsequently successful recreation of acoustic sound in three-dimensional space. Without confusing an already difficult issue, acoustic sound occurs in time and, therefore, adds its fourth dimension to the three dimensions of height and depth and width that construct the "staging" and "imagery" of convincing acoustical reproduction.

Music is "all about the sound." And cables are "all about music" when they achieve refined clarity and timbral delicacy. I regard my work with cable design to be an art as much as a technologically-based engineering practice defined by measurements and decisions based on verifiable performance evidence. The choice of materials used in cables in of great importance. Design structures chosen to craft those materials is not a jot less important.

For me and for Acoustic Zen, cables are seen to be enmeshed in all phases of music- creation. Our aim, thus, is to create inherently "musical" cables . cables that are physically sympathetic to musical signals. A quick look at how central cable-design and cable crafting are to the world of music is revealing.

At the moment of creation, microphone cables receive music as it is recorded. Cables through-out the recording chain preserve and transmit (or, alas, unwittingly degrade) signals captured at the microphone interface. Ultimately, post-production delivery of a completed recording depends upon all the cables and interconnects that transmit music from its reproductive source (a DVD/CD player, a turntable, or a tape machine) across pre-amplification and amplification and on to speakers that divulge musical provocation, power, and engagement.

Cables, in sum, are everywhere music is at stake and that is why research into the design of cables -- and into materials that comprise them -- is crucial to improving the creation of music from its source to its end result as listening enjoyment.