Jonathan Weiss, founder and CEO of Oswalds Mill Audio, born in New York City, studied International Relations and Political Philosophy at Princeton University, and Public International Law at London School of Economics. After years of travel Weiss changed direction and became a filmmaker. He produced and directed a full length feature adaptation of J.G. Ballard's infamous non narrative novel, The Atrocity Exhibition into a similarly non narrative film. After discovering Oswald's Mill in Eastern Pennsylvania, a vast restoration project, he embarked on a new direction for audio with OMA.
INTRO
In a world defined by mass production and marketing, OMA stands out as clearly being from another, parallel universe. OMA products have a unique design philosophy. Instead of following current trends and embracing so called "cutting edge technology," we took a look back.
There was a time, in the early part of the Twentieth Century, when the creation of horn loaded loudspeakers, field coil and full range speakers, tube amplifiers, and analog reproduction represented the highest technical challenge and achievement. As time went on, every new innovation in sound, from solid state to digital to file sharing, turned out to bring the overall quality of sound in our lives to a lower level. People not only forgot what great sound reproduction sounded like, but at this point, most have never even heard it.
OMA can't change the world, but we can create a new path for audio. Not by using the technology that guides the space shuttle, but by going back to the technology that worked so well and was never surpassed. It was, however, nearly forgotten. No one has ever improved upon the violin makers of Cremona over 300 years ago, and the same can be said for the professional audio equipment made for cinemas and studios in the 1930's through the 1950's. This is the world of OMA. Hand built to the same exacting levels as the vintage gear which inspired us, OMA makes loudspeakers, amplifiers, and turntables out of solid Pennsylvania hardwoods, slate, and steel. Equipment without a peer, made for those who understand that the finest things in life are not necessarily the newest.
Oswalds Mill Audio is an odd name for an audio company. Who is Oswald? What does a mill have to do with audio? It does suggest some kind of story...
A good place to start is with Oswald's Mill itself. It is the only known example of an integrally built “house-mill” left in North America. Only 8 or 9 are left in the world today, in Southern Bavaria and Northern Switzerland, where the people who settled in Eastern Pennsylvania came from. Mills were made to grind grain, but in Germanic Europe, where large building materials were already scarce by the 16th Century, it made sense to build a house and mill into one structure to save on material and labor. That did not make much sense in the new world, where the colonists were greeted by enormous trees to be felled, and rock to be cleared from fields, but old habits evidently die hard. Sometime about 1800, the Oswald family built an enormous stone mill and a house together, 4 stories and 10,000 square feet, with water rushing through the middle to power the wheel and grinding stones. Mill's don't have walk in fireplaces, bedrooms, chair rail, and the other accouterments of domestic living, but this one did.
The Oswalds made a lot of money, and must have discovered that living in a grist mill, which is noisy and full of flour dust, was not to their liking, so they built a new house up the road and moved out of the part of the Mill which was their domestic quarters. The mill itself shut down around 1900, a casualty of the industrial revolution, which had finally made its way into agriculture and food production. With no one living there, and no milling to be done, the Mill sat empty for almost another hundred years. Until the day I saw it.
I was not in the market to buy a mill. In fact, I was completely broke. I was a filmmaker, and had just directed my first feature film (The Atrocity Exhibition, from the book by J.G. Ballard). I was living in New York City, where I had a huge loft which was also my film studio. The sound engineer on my film was from Pennsylvania, and had bought a run down but beautiful old farm there, and I often visited him to help with the renovation. One day another character helping out on the farm suggested we take a drive to a very special old building he thought I should see. That was Oswald's Mill.
I think I might be strange in that every major decision I have made in my life never felt like a decision at all. When people talk about decisions, I assume a process that involves careful consideration, weighing different factors and outcomes, and so forth. I've never done that. It always just seemed obvious what I should do. Sometimes the “decision” did not lead to the outcome I thought it would, like with my education (I studied International Relations and Political Philosophy at Princeton, and Public International Law at London School of Economics, but ended up a filmmaker, for which I had no education). But that never bothered me, because life is not composed of straight lines. When I found my loft in NYC, I knew it was the right place instantly, as I knew my wife was the right person to spend the rest of my life within the first 10 seconds of meeting her. I just knew those things in my bones.
When I got out of the car and looked at this huge, incredible stone building, partly hidden by trees and weeds which threatened to swallow even such an enormous structure, I already knew it was trouble. My friend led us around the back to a loose piece of plywood where a door should have been. As soon as I was inside for five minutes, I was done. I figured out a way to buy the mill, and began a process of restoration that is still not finished, 16 years later.
It was a very, very big job, and I had no idea what I was getting myself into. The mill had no electricity, no windows, no plumbing, no heating, no kitchen, no bathrooms (obviously) no well, and no septic system. On the positive side, it was the only one of its kind outside of Europe, and because no one had lived there for a hundred years, it was completely original- no linoleum, formica, plywood cabinets, and other signs of life in the 20th Century.
A few years later, with the utilities and other necessities installed and the mill now a livable space, I realized that I had 10,000 square feet of empty space on my hands, surrounded by 2 foot thick stone walls and no neighbors. The same fellow who had taken me to the Mill in the first place had been involved in sound twenty years earlier. He DJ'ed at places like Studio 54, with big Altec Lansing Voice of the Theater cinema loudspeakers, McIntosh tube amps and broadcast idler drive turntables. We talked about that a lot. I had worked in a movie theater when I was 14 years old in Westwood, California- the Bruin Theater. It was really an art deco movie palace from the 1930's, and was used for world premiers, like Apocalypse Now (I just missed that one) and American Gigolo. It had a fantastic sound system, with the biggest Altec speakers (A2's, over 2 meters tall) and tube amplifiers. If the projectionist liked the soundtrack, I'd be hearing it at 105db when I got to work in the morning before opening, to clean up the popcorn and soda left by the late show the night before. To hear Blondie singing Call Me at simply astonishing loudness levels with no strain, distortion or other artifacts turned out to be a life changing experience. Because I never forgot that deep, physical pleasure in sound, and I always wanted, in the back of my mind, to replicate the experience.
My friend remarked that with all that space, and no neighbors, why not try and recreate the cinema sound experience? With the internet in its infancy, this turned out to be more difficult than expected, but eventually I found movie theaters in New York City and elsewhere being demolished or renovated, and that yielded excellent results. Soon I had a pile of very large horn loaded speakers, and very little idea of what to do with them. There is simply no manual for this kind of thing.
RCA, located in Camden, New Jersey (across the river from Philadelphia, an hour from the Mill) created some of the first and best theater sound systems from the 1920's, and continued its Cinema Products Division until closing 50 years later. I found retired RCA engineers and began a long process of understanding how these kinds of sound systems were designed and operated, all the way back to the beginning of sound in movies. These engineers were quick to explain that some of the earliest speakers and amplifiers made by RCA were also their very best. That knowledge and their help pointed me in the direction of assembling very rare, early equipment that literally no one in the world (at the time) was using. One reason is that no one had the space to do so, even if they would have wanted to.
Word began to get out about this guy in a big mill in the middle of nowhere with speakers so efficient that they could blow you away with a couple of watts of power. Other essays in this About section explain this aspect of horns, but the tremendous sensitivity and efficiency of big horn systems like the mill's meant that you could use any amplifier, even ones using rare, vintage triode tubes which people had started building themselves. Such amps were the domain of a tiny group of insanely devoted audiophiles with highly developed skills, who communicated with each other largely via the internet. These low powered, usually single ended triode amplifiers (known as SETs) were almost impossible to buy in the US at the time, so it was very much a DIY field.
For a SET amp to sound its best, a really big and efficient speaker is needed. Very few people had anything like that, but when this crowd discovered Oswald's Mill, an annual event crystallized, and became known as the Oswalds mill Tube and Speaker Tasting. It soon took on a rather mythical stature, and people were coming from all over the US and Europe to attend. Even at this point, it did not occur to me that the audio business was in my future.
Two of the people who attended the Tastings decided to go professional, and build a new version of a very special, legendary field coil loudspeaker driver which we all loved- the RCA MI-1428B, which ceased production around 1939. This was a unique driver, with nothing like it before or after in the history of sound. Of that duo, one was an aerospace master machinist, the other a master piano technician who tuned concert grands, and neither had any experience running a room at an audio show. So they asked me if I was interested in that job.
When I got to my first audio show, the Rocky Mountain Audio Fest in 2005, I had never read an audio magazine, never shopped in an audio store, never owned any consumer equipment, and had no idea whatsoever what the mainstream hifi high end market was like. It was a real shock. I walked into room after room, hearing the same kind of awful sound coming out of ugly equipment with price tags that belonged on vintage sports cars, not MDF boxes.
I began to realize that there was something terribly wrong with this commercial audio world, akin to the Emperor's New Clothes. The years of experimentation and the Tastings had taught me what great sound could be like. Restoring Oswald's Mill had introduced me to the enormous potential of the surrounding area of Pennsylvania, the birthplace of the Industrial Revolution in the US. With companies like Bethlehem Steel, a 200 year history of machining, wood working, and high tech small manufacturing, anything could be fabricated within a short distance. The local forests provide hardwood of such high quality, like black walnut, cherry, and ash, that most is exported across the globe. And I became friendly with the owners of the last functioning slate quarries in Pennsylvania, a priceless material for the construction of audio products. In short, it was another decision which just happened, it didn't even need to be made.
OMA continues to be the joint effort of an incredibly talented group of world class experts in their field. Bill Woods is one of the world's top horn designers and is responsible for all acoustical engineering of OMA speakers, while industrial designer David D'Imperio translates those designs into the compelling forms for which OMA has become known. Our circuit designers include Paul den Hollander in the Netherlands, and Jonathan Knight in Japan. Cynthia van Elk is our photographer and graphics designer, and Justin Wagner our web designer.
ON THE HISTORY OF AUDIO
When we think of the history of audio, it appears to be a series of continuous improvements, from primitive origins to our current state of the digital art. The earliest recorded music, Edison wax cylinders from the 1890's, were indeed crude, just as iPods and iPads are extremely sophisticated. No one wants to use a television or computer from 5 or even 10 years ago. Yet somewhere in the progression of music reproduction technology in the 20th Century, the quality of sound did not improve and even declined. This deterioration is so counter-intuitive it requires more than just an explanation. We need to look at the history of audio reproduction to understand what happened.
ORIGINS
It's impossible to know when man started to make music. Perhaps it was even before man was human, or Homo Sapiens. It is safe to assume it was a very long time ago. Some conjecture that music is a defining quality of what makes humans human. But one thing is certain- for at least tens of thousands of years, when music was made, you had to be present to hear it. A much larger number of people played an instrument, or sang, because that was simply the only way to have music. The advent of musical reproduction should be seen as a watershed in human civilization, and a high point in the history of technology. And the history of musical reproduction turns out to reveal a hidden secret about technology in general, one that belies our implicit faith that technology is like evolution in the natural world.
Virtually everyone today is immersed in music. It may come from your iPhone or iPod, but you certainly endure it in nearly every shop, store or public venue. Music is everywhere, and for most, costs nothing. And what costs nothing, is often considered without value.
When music was first reproduced, the situation was entirely different. The fact that you could hear music without being present for its live performance was nothing less than magical. Before electronic microphones, musicians and singers had to perform into long conical horns, which fed a mechanical transducer that cut the signal onto a cylinder and later, a record. It was the actual force of the voice or instrument which physically moved the transducer which created the signal on the recording medium.
Electronic microphones arrived in the 1920's, and changed everything. A voice or instrument could now be electronically amplified, and anything could be recorded, such as a symphony orchestra.
The 1920's were a period of unprecedented prosperity in the United States and Europe. An enormous amount of money and effort was expended in the US, Germany, and elsewhere to develop the technology for advanced sound reproduction- meaning the telephone, microphones, recording technology for records, radio, and of course, talking motion pictures. Movies were an integral part of life like television or the internet are today. There were newsreel theaters in major cities that functioned like television, and ran 24/7. The invention of the “talkies” or movies with sound was an enormous event. It immediately and permanently changed film and all media.
Two huge corporations would literally dominate American and even worldwide communications technology for most of the 20th Century: RCA and Western Electric. These companies were responsible for nearly everything we take for granted today- the telephone system, RCA (at the time Victrola) invented record technology, created television, the VCR, and both were responsible for virtually all of the seminal development of sound for motion pictures, which is the reason for this essay.
It's useful to remember that in the 1920's and early 30's, when the most significant theoretical and engineering work was being done by W.E (Bell Labs) and RCA, there were no computers, no space program or nuclear energy or weapons, and WW2 was not even on the horizon. The best minds in the world were working on the problem of how to reproduce sound effectively and realistically, and one of the most difficult challenges was how to make sound work in movies. It obviously requires a lot of sound, and that was a problem.
Theaters were not the small multiplexes of today. They were usually enormous caverns often holding thousands of people. Theaters have lots of upholstered seats, heavy drapery, and the audience themselves absorb a lot of sound, making sound reproduction even more difficult. The demand for loudness was great, but the first generations of amplifiers, which used the simplest type of vacuum tube, called a triode, produced very little power, usually not more than 10 watts per amplifier. Even if you had multiple amplifiers, which were very large and expensive, the total power available to produce credible sound for a big audience was tiny, much less than any mass produced audio amplifier made today. How did they turn so little power into so much sound?
THE GOLDEN AGE
The answer was horns. Not that horns were a new thing- since antiquity, horns were used to make music, to communicate over long distances (those long Swiss ones) and to destroy buildings (Jericho, the Old Testament.) Engineers at Bell Labs and Western Electric (Wente, Thuras, Fletcher) and RCA (Volkman, Masa, Olson) took horns to a new level. These new horn loaded loudspeakers, which were very large and located behind the screen (see the essay “Why Horns”) were so efficient that they could convert the tiny electric power of the triode vacuum tube amplifiers into plausible, realistic sound levels in even the largest theaters. Without the aid of computers, in an almost miraculous way, these engineers mastered problems in acoustics and psycho-acoustics which are difficult even today, with our battery of modern technology.
Even die hard audiophiles, including the people who write audio magazines in the US like Stereophile or The Absolute Sound have never heard (or have any idea) about this combination of low powered triode amplifiers and large, horn loaded speakers. It has become the secret domain of a tiny group of advanced audiophile collectors, mainly in Japan and Asia, who have bought most of the vintage equipment that remained in North American theaters after World War II. There are only a few hundred such systems in use in the world today. What happened to make something that sounded so good simply disappear?
THE SLOW DECLINE
Most of us measure technology by its benefits. Computers get smaller, thinner, lighter, cheaper and more powerful every year. Those computers now allow us to store inconceivable amounts of information for a tiny sum, including music. Convenience and economy would seem to be the end of the story for most people, who now view music as wallpaper, background, or just distraction. Music is no longer an event, an end in itself, or most importantly, a source of deep pleasure and spiritual renewal. It can't be, because it has been hollowed out at the core. This destruction has happened in several distinct ways. Let's start by looking at why those great cinema loudspeaker systems from the 1930's disappeared.
CHEAPER, NOT BETTER
Before WWII, all cinema loudspeakers, which were mounted in horns, used a speaker “driver” which is essentially an electrical motor. An electrical signal (from the movie soundtrack) is turned into mechanical movement (of the drivers diaphragm) and this produces the sound, which is greatly increased by the horn. In the early days of cinema sound, permanent magnets powerful enough to make the driver work properly did not exist- the metallurgy after the war made them possible. The early drivers all used “field coil” technology, which was electromagnetic. These field coils were very expensive to make, and because the permanent magnets were so much cheaper, the early technology was discarded as soon as possible (after WWII.)
Equally important, the triode amplifiers of the first generation of sound systems, being low powered, were quickly replaced by pentode and tetrode type vacuum tubes, which were acknowledged to sound inferior, but again were cheaper and produced far more power.With the economic boom in the US after WWII, and the introduction of the LP record, and a lot of men trained in electronics by the war effort, home audio enjoyed enormous popularity. Because sound was monophonic, only one speaker was necessary, and they were always large, and virtually all of them used at least one horn, a vestige of the work done on cinema sound decades before. These speakers were all high efficiency, because amplifiers for the home rarely boasted more than 20 watts of power.
Power in audio is of the utmost importance, because it dictates how efficient, and thus how big, your speaker must be. Low power means a big speaker, which is a more expensive speaker, but a better sounding speaker. With more powerful tube types, speakers could be reduced in size and cost. The tipping point came with the introduction of solid state amplifiers; transistors replaced tubes entirely. If a watt of tube amplifier power cost $10, a watt of solid state cost 25 cents. Suddenly, loudspeakers did not have to be large at all- you can engineer a tiny speaker to produce the same sound pressure level as a big speaker, if you hit it with 100 times the power. Since power was cheap, and efficient speakers were expensive, the combination of cheap power and cheap, small speakers drove the audio industry into a downward spiral of sound quality from which it has never recovered. Solid state amplifiers continue to increase in power and decrease in cost. In turn, speaker manufacturers reduce the size of their product to conform with the perceived desire of the consumer for a speaker as small as possible. The actual result is ever worsening sound, with most people today having no real stereo system at all, and a tiny, insular “high end” audio industry which is dying.
DIGITAL VS. ANALOG
Few things are more deceptively simple than the vinyl record. It has been around for over a century, so how could anything that old work so well? Just as the original patent for the moving coil loudspeaker of Rice and Kellogg (1924) nailed the design of every cone speaker ever made since, the record was a stunning technical achievement which is still unsurpassed for audio quality (excepting master tape, from which records are cut.)
It sounds vaguely Luddite, but the earliest vinyl format, the 78rpm record, is still technically by far the best. Almost all surviving 78's have a lot of groove damage (played by countless steel or cactus needles) and surface noise, but if you listen past that, something amazing happens. There is a lifelike quality, which is no mystery- 78's spin much faster that 33rpm records, and with faster playback speed, more sonic information is conveyed. But 78's only contain a few minutes of music per side, and were quickly replaced by the LP or Long Playing Microgroove record, the monophonic precursor to stereo sound.
Records, whether 33rpm, 45 or 78, contain musical information in the “analog” format, which means the signal is continuous. A little tiny diamond point, sitting on the end of a tiny stick of aluminum, sapphire, boron or other material (the “cantilever”) literally traces the musical signal in a record's grooves which look like squiggles and bumps. That tracing movement is turned into incredibly tiny electrical signals inside the cartridge, by the movement of magnets or coils at the other end of the cantilever. It's like an electrical motor, but in reverse. This is all taking place at a physical scale so small it belongs in nanotechnology, with electrical signals that can be so infinitesimal that they are nearly on the molecular scale (pico volts.) The fact that this works at all is remarkable, but that it works better than anything we have today, in terms of sound quality, is mind boggling.
The problem with records is that they were expensive to make, as were record players and everything associated with analog reproduction. The compact disc was supposed to take care of that- no more scratched or dirty records, broken needles, and of course, the CD was far cheaper to make, about 20% of the cost of making an LP. The original marketing slogan for the CD was “Perfect Sound Forever” TM even though it was understood by Philips and Sony, the creators of the CD, that the sampling rate was far too low, with the final irony being that the material from which CD's were made is now decomposing quickly, rendering many, if not all CD's worthless in the future. The unintentional byproduct of making music digital, for the music industry, was its own destruction. The major labels used the introduction of the new format and technology to both raise the price of music for consumers (CD's were more expensive to buy than LP's, even if much cheaper to manufacture) and force people to abandon their analog music collection to conform with the new market reality. What they never anticipated was a Pandora's box- with music now a stream of bits, it could be easily and endlessly copied, destroying the market for the physical purchase of music.
It has been 30 years since the CD format was introduced, and by now, even in the high end audio industry, no one is saying that digital is better than vinyl. If you open an audio magazine, it's common to see ads for extremely expensive digital players which suggest that their product is “as close to analog” as possible. It's also useful to note that although there are many technical theories as to why vinyl and analog are better than any digital medium, there is no proof as to why this is so. Human hearing is so complex and so accurate that science has not been able to fully understand why we can hear what we hear.
With digital file sharing, the MP3 format, Apple and iTunes, an already poor situation was made much worse. To enable easy and fast transmission of music files, not to mention ease of storage, compression was employed resulting in the (permanent) removal of as much as 80% of the original information. If we were to look at an image which had that much information removed, our impression would be negative. But the brain is very adept at filling in missing sonic information, based on a set of presumptions about what the unaltered musical signal should be. Thus even though low bass may not be present in an MP3, or on our headphones, our brains make believe that it exists. This wondrous ability comes at great cost, however, which is known technically as “listener fatigue.” Because hearing is such an unconscious activity, we are unaware of the brain's work in restoring damaged or altered sounds. And since virtually no one sits down to seriously listen to music anymore, instead using music as a soundtrack to other activities, listening fatigue isn't much of a problem. It does help explain why most people don't own real stereo systems today- with digital, it's not much fun to really listen to music.
On the professional side of digital audio, an equally disturbing phenomenon occurred in the middle 1990's. With analog, a vinyl record can only be cut so loud, because if cut too loud, the needle will literally jump out of the groove. The record will not be playable. The CD has no such physical constraints, but until 1994 with the introduction of digital limiters, digital music was still recorded with dynamic range, which is defined as the relationship between the quietest parts of a recording and the loudest parts. Because record producers wanted their acts to sound louder over the radio than the competition, with the new technology they could eliminate dynamic range and make their music “seem” louder- by destroying a vital aspect of what makes music music. By the 2000's, this phenomenon was referred to as the “loudness wars” and defines most digital music production today.
CONCLUSION
Technology is now advancing at such a rate that the amount of literature generated by it doubles every few years. Increasing specialization in the sciences and engineering has become necessary because no person can master even a single discipline with the proliferation of knowledge and information in any field. If you wander around an A.E.S. convention (the Audio Engineering Society, the worldwide professional association for audio) you can see the problem. Everyone is focused on a solution to their particular area of audio, improving digital algorithms, or reducing jitter in clocks, but the big picture (how does it sound?) is lost.
Scientists, engineers, and industry professionals furthermore are ignorant of the history of their field, and harbor a prejudice that with time, knowledge is both increased and perfected. In other words, history is irrelevant. In audio this is clearly not true, but to even acknowledge the possibility that prior art was superior would be epistemologically destabilizing.
We assume that technology is a progressive force, continuously improving and making our lives better. Looking at the history of sound reproduction belies this belief. Yet there are glimmers of a counter-movement. The sales of vinyl records are growing enormously every year. That has led an avant-garde of enthusiasts to discover vintage audio equipment, and even more esoteric horns and triode tube electronics. These are the people who listen with their ears, not their minds.
WHY HORNS
In another part of the About section (On the History of Audio) I describe how horn loaded loudspeakers were the first to be used in audio, and why they were later abandoned. Our project at OMA is to reverse this course. Let's start with loudspeakers, because that is ultimately what you listen to in an audio system.
A loudspeaker is a transducer- it transforms an electrical signal (like music or speech) into the physical movement of a cone, or diaphragm- basically something that will move air and make a sound wave. It's a very simple system, and you do it yourself, albeit organically; an electrical signal from your brain is sent to your vocal chords, which move and make sound, which is hopefully intelligible. If you put a megaphone to your lips, that sound is far louder, and will carry much further, too. You've increased the efficiency of the system exponentially with the horn. Because the horn makes your voice so much louder, you won't shout yourself hoarse. The same thing happens when a horn is added to a loudspeaker- the speaker can relax and not strain, and this is extremely important for good sound.
Regular loudspeakers, such as a cone in a box, or even worse, electrostatic or planar speakers, are incredibly inefficient. A typical speaker (85dB/1w/1m@4ohm) is .1% efficient! That means that for 1000 watts input, you get exactly 1 acoustic watt output. An acoustic watt is actually a lot of sound, but compare a horn loaded loudspeaker, which can easily be 60% efficient (108dB/1w/1m@8ohms) or 600 times more sound from the same input as the regular box speaker. Imagine we have two loudspeakers, a conventional one (the 85dB one) and a typical high efficiency horn speaker (105dB/1w/1m @8ohms). To reach a realistic sound level of 96dB at one meter, the conventional speaker needs 50 watts of power. The horn speaker needs less than half a watt.
Many solid state amps produce 500 watts or more, so power is not so much an issue (except on peaks in music, which can easily reach the maximum of even a powerful amplifier). The problem is thermal. When you pump hundreds of watts of power into the incredibly thin wire which is the voice coil at the end of the speaker cone, it gets very hot. This heat causes “thermal compression' which creates distortion as sound gets louder. This compression is never an issue for horn speakers used in the home (it can be in a rock concert).
For any speaker to make sound, it must move air. The movement of the cone or diaphragm, forwards and backwards, creates the sound wave, and a critical fact is how much the speaker has to move to make the desired level of sound.
If we stood 6 feet apart in a swimming pool and I wave my hand towards you underwater, you will feel a vague wave of pressure. If I have a 2 foot long, 4” diameter pipe, and I hit my hand against one end of the pipe while aiming it at you, you will feel a much stronger wave. The pipe couples my hand to the water far more effectively than simply waving it, because without the pipe the water goes everywhere, not just where I want it. This is exactly the difference between a normal direct radiator speaker and a horn, which is just a flared pipe. The cone in a regular speaker also has to move a much greater distance to create the same sound pressure as the horn. And when the cone moves, it does not instantly stop when the signal does. It can't- its a moving thing with mass and inertia, and so it oscillates back and forth, the more so depending on how much it has to move in the first place. Imagine a recording of a drum thwack. The speaker cone moves out to convey the strike, then backwards, and keeps doing so even though the drum strike is over. Since horns and high efficiency drivers have to move so much less to convey the same sonic information, they stop moving quicker. The sound does not get smeared, seems more real, more lifelike, faster.
In a room, a conventional box speaker produces sound which travels in all directions. Some sound wraps around the speaker and heads towards the rear wall, some goes to the ceiling, the floor, and the side walls. Some sound also reaches you directly; this is called the “near field” which is defined by a predominance of direct sound over reflected sound which reaches you later. Reflected sound, if delayed enough, does not sum with the direct sound, and the result is confusion for your brain. If the room is very reverberant, you have echoes and a complete loss of intelligibility. People with normal speakers often go to great lengths and expense to acoustically treat their rooms with absorption to combat all these reflections.
With horns, this problem is greatly reduced. One thing that horns do so well is direct the sound to where you want it. If you aim the horns where you sit, the vast majority of sound gets to you, not the rest of the room. This gives horns a much larger “near field” and that improves imaging (less reflections means more specific stereo image) and lets your brain relax because it doesn't have to figure out what to do with reflections. Crosstalk cancellation is also far better, for the same reason (that's a complicated subject in itself).
Horns in general obviously have a lot of important advantages over conventional speakers, but not all horns are created equal. In the audio world, many horns have acquired a reputation for sounding “shouty”, colored or nasal. Indeed that can easily happen if the horn is not properly designed, but the real culprit is the practice of curving the walls of a horn, like a trumpet, to increase the efficiency while reducing the overall size. If you blow into a megaphone, which has straight sides and a very open throat, the sound is loud and clear. When you blow into a trumpet, with a tiny, constricted throat the sound is much louder, but also sounds like a trumpet. The megaphone is a conical horn, the only type made by OMA. In fact, OMA is the only hifi company in the world making conical horn loudspeakers. Every other company uses curved horns. One reason why conicals have been overlooked is size. A conical horn is much larger for the same bandpass (the frequency that the horn covers) than a curved horn. In an industry obsessed with reducing size, conicals have never even been on the map. But only conicals can have a completely natural presentation of music, and also “constant directivity.” This term refers to how even the dispersion of sound is within the field defined by the shape of the horn. So if a conical horn has a flare of 60 degrees, and you walk around in front of it in that segment of space, the sound will be constant, even as the frequency goes up and down. Curved horns do not have this quality, which is why you usually seem them pointed directly at the listening chair. As the frequency goes up, the horn “beams” and the sound becomes focused like a laser, so if you are not sitting right where the two beams come together, you will miss part of the music. You don't have to have your head locked in a vice to enjoy OMA speakers. Everyone in front of them gets to enjoy the same sound.
All speakers require an amplifier, to increase the electrical signal coming from the source, whether it be a microphone, a record player, CD or DAC. The amplifier has to have enough power to drive the speaker to the desired sound pressure level (SPL).
Amplifier power is given in watts, and SPL is measured in decibels (dB) The decibel scale can be very confusing, because it is not linear, it is log-arhythmic. Every 3dB increase in level (SPL) which is pretty much the smallest db difference you can hear, requires double the power from the amplifier. And if you want to double the perceived level of sound, that requires a 10dB SPL increase. That extra 10dB will require ten times more amplifier power. If you listen at a normal level of 88dB, for example, and you want to turn the music up to a loud 98dB, that demands an amp go from say 50 watts of output to 500 watts. Musical peaks, such as with symphonic orchestras or in rock can exceed 20dB. That would most likely put your amplifier into red line territory.
What this means in reality is that with conventional speakers you must have enormously powerful amplifiers to play at the same level as a tiny amplifier with a high efficiency (horn) loudspeaker. The big amplifier will still be struggling while the little one will be happy. This has some very significant implications.
Because solid state amplifier power has only gotten cheaper (especially with the new Class D switching amps) speaker manufacturers have reduced the efficiency of their wares which allow a small woofer to produce very low bass (important for marketing and magazine reviews) and have an equally small package. Solid state amplifiers are designed to produce brute power, they don't have the finesse, detail and lifelike quality of the best tube amplifiers, especially the triode tube ones which are typically under 10-20 watts. These amplifiers are designed with the first watt as a foremost priority- that is the watt you will be listening to most of the time (with horns). The rest is reserve. There is a world of difference between the first watt of a SET amplifier (single ended triode) and a 100 watt plus solid state or even tube amplifier. It's only with horns that you get the full beauty and impact of the best sounding amplifiers.
A further consideration when pairing a speaker with an amplifier are electrical parameters which never get proper coverage in the magazines or online. Besides impedance, the “damping factor” presented to the speaker by the amplifier is a significant factor in sound quality and especially, bass reproduction. A speaker actually forms an electrical circuit with the amplifier, it's a two way street, so to speak. Every woofer has a “damping factor” which is the force necessary to restore the woofer to equilibrium after movement. The amplifiers output stage can have a very wide range of damping factor. Low efficiency speakers get a lot of bass from little woofers by making them move a great distance, which means they need a very loose “suspension”- the surround of the cone that allows it to move and keeps it in place. Such woofers need a high damping factor to make them behave. High efficiency woofers are larger, have stiff, light paper cones with big magnets and move very little. They need very low damping factor, which is typically what SET and other low power tube amplifiers offer.
While the complexity involved in assembling a horn loudspeaker system may seem daunting, the results when successful far surpass any other loudspeaker technology. Dynamics are one of the most important attributes in what makes reproduced music sound real, for example. Amazingly, in the audio world with all of its tests like frequency response, acoustic and electrical phase, waterfall plots of time domain response and so forth, there exists no test for dynamics. Horns are the only type of speakers with realistic dynamics. With horns, problems with room acoustics are dramatically reduced. The range of amplifiers that can be used with horns is limitless. Distortion is radically reduced. The sound is spellbinding. But of course, there is one more thing to consider. Horns can be beautiful like no other speaker.
THE PROCESS
All OMA products are made in the immediate environs of Oswald's Mill in Eastern Pennsylvania. Most are made by hand, though sometimes aided by very high tech engineering. To understand what we make, it's useful to know the processes involved.
Our slate, from which our turntables, plinths, equipment racks and even some amplifiers are fashioned, comes from the last two functioning quarries in Pennsylvania. It is cut on a state of the art five axis water jet machine owned and operated by a Mennonite family, surrounded by Mennonite farms. Once cut, the slate is honed by hand using water and diamond tooling and abrasives.
Our foundry has been owned and run by the same family for four generations. It specializes in cast iron and bronze, the most ancient metals. Working closely with the foundry master, our new products such as the Ironic cast iron loudspeaker employ cutting edge fabrication technologies, such as 3D printing the sand molds used to cast the Ironic, and using special hypo eutectic high graphite grey iron for its non resonant, anti vibration characteristics. The bronze throat castings for our AC1 loudspeaker demonstrate the foundry's long history producing exquisite architectural details.
Our hardwoods (black walnut, cherry and ash) grow in the surrounding forests and are sustainably harvested. They require two years of air and kiln drying, usually in solar kilns which gently heat in the day, and cool at night, allowing the wood to release tension and provide more stable lumber, critical for our loudspeakers. We buy our wood in the form of "boules", an entire tree slab cut so that every board will match in color and figuration.
Once the wood has been properly conditioned, our master woodworkers build our loudspeakers, amplifier chassis and other components by hand, the old fashioned way. This takes far more time, is more expensive, and ensures a superior product.
CONTACT T 917 743 3780
http://oswaldsmillaudio.com/