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Guide to high accuracy sound reproduction
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| It is possible to reproduce a stereo
recording in an ordinary living room such that listeners have the illusion
that the two loudspeakers have disappeared and when they close their eyes,
they can easily imagine to be present at the recording site.
The vast majority of loudspeakers that have been sold - the typical box speakers - can only produce this effect to a limited degree because of a fundamental limitation: they radiate sound into the room with different intensity at different frequencies and angles, though flat on axis. Thus the many reflections from room boundaries and surfaces become sonically colored in a way that is characteristic for this type of loudspeaker and we always recognize the sound as coming from a box rather than being live. It is the generic loudspeaker sound. Loudspeakers with frequency independent, constant directionality such as omni, dipole or cardioid loudspeakers, create delayed replicas of the direct sound in a room and fewer colored reflections. Our ear/brain perceptual apparatus does not get confused by replicas. Instead it relegates them to the earlier learned acoustic behavior of the room and readily blankets that information and thereby the room. This automatic response is part of the Precedence Effect in psychoacoustics and it is essential for creating the illusion of "being there" and not just in your living room. It has been a fascinating journey for me to come to this understanding. Early on, electrostatic panel loudspeakers had intrigued me because they seemed to do something fundamentally right when properly set up and this despite their obvious limitations. I can see in hindsight that a few loudspeaker designers had pointed to the benefits of omni-directional loudspeakers. The ORION+ has demonstrated to me what is possible in 2-channel sound reproduction, given that the recording contains natural spatial cues and is not merely an artificial sound mix. Accurate sound reproduction is in reach for you too. Surprise yourself with the illusion that two loudspeakers can create when they properly stimulate your room, ear and brain. You find yourself lost in the music. March, 2008 |
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These are the ORION loudspeakers. You can purchase them as a complete custom-built system including all electronics, cables and interconnects and ready to be plugged into your preamplifier. You could also build up everything yourself from the available extensive documentation, material lists, and blank printed circuit boards. We can even help with pre-cut wood and assembled electronics. Depending on your construction skills, time, and money, there are several ways to obtain a pair of these outstanding loudspeakers. |
You have come to a website with a wealth of useful and practical information about loudspeaker design, electro-acoustic system design and about perception of sound from loudspeakers in normal rooms. I have been active in this field for over 40 years, motivated by my love for music and by a keen interest in the difficulties of reproducing music realistically in the home.
After retiring from Hewlett-Packard Co. (now 'Agilent') with 37 years in R&D of radio-frequency and microwave electronic test equipment, I pursued my investigation of the loudspeaker-room-listener interaction with refreshed energy and time. In the late nineties I had developed the Beethoven/Dvorak/Vivaldi line of open-baffle loudspeakers for Audio Artistry. My objective has always been the development of cost effective loudspeaker systems for two-channel sound playback of the highest accuracy. Occasionally I experiment with surround sound. Video sound and moving pictures are of low interest to me, but digital photography has rekindled my lifelong fascination with pictorial expression.
On this site you will find the essence of what I have learned from designing, building and listening to many different types of speakers. Fortunately, I was rarely bound by commercial considerations or restricted by market expectations. I was free to search for the parameters that are truly important to realistic reproduction. Throughout this search, my sonic reference has always been the non-amplified original performance.
You can use the information in these pages to learn about sound reproduction, room acoustics, loudspeaker design and related subjects in order to build your own speakers, to understand the theoretical background behind different designs, or to optimize what you own. Five projects are described in full detail:
- PHOENIX, a full-range, open-baffle speaker with separate dipole
woofers
- THOR, a sealed box subwoofer and its addition to ORION or other speaker
- ORION, a compact and highly refined open-baffle speaker with integrated
dipole woofers
- PLUTO, a small size, closed-baffle, omni-directional speaker
- PLUTO+, a full-range, omni-directional speaker with outstanding
performance
Construction drawings and complete technical explanations of their design are provided. I also sell blank printed circuit boards to simplify the assembly of the crossover/equalizer electronic circuits.
 PHOENIX main panel and separate dipole woofer in W-frame |
A study of the PHOENIX project will give you useful
insight into the theory, design and construction
of an open-baffle speaker and the necessary line-level crossover/equalizer. The
completed system allows you to experience
the
room-acoustic benefits of dipole radiation.
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THOR is a sealed-box, monopole subwoofer. It could extend your sound system's very low frequency capability or it can be added to the ORION in a Home Theater setup. The theory, design and construction details given in these pages make building the THOR a worthwhile first do-it-yourself project.
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 ORION with optional THOR subwoofers behind it |
The ORION loudspeaker has a smaller footprint than the PHOENIX to fit the widest range of domestic situations. It is an open-baffle loudspeaker of the highest sonic accuracy and refinement. It incorporates not only what I learned from previous exercises, but also takes advantage of the latest in driver technology. You can purchase construction plans for it as well as all necessary assemblies. You can build it yourself from grounds up, at an estimated cost of $2200 plus 60 hours of your labor, or you can have it completely built by us.
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PLUTO is a much smaller and lower cost 2-way speaker that captures many of the desirable characteristics of ORION, yet is based on the conventional sealed-baffle speaker concept. PLUTO is self-powered and well suited to a very wide range of applications and environments. It can be build at a cost of only $700 and 30 hours of work. You can also purchase PLUTO ready built and, if desired, add subwoofers at a later time. Thus you would enjoy a loudspeaker system that seriously rivals ORION, but is better suited to smaller listening environments.
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PLUTO can be upgraded to PLUTO+
by adding two closed-box subwoofers with outboard
crossover/equalizer electronics and power amplifier. This 3-way system is a worthy alternative to the
ORION and in many respects its sonic equivalent, though at considerably lower
cost and simpler construction.
Whether sealed baffle PLUTO+ or open baffle ORION,
they each offer highest accuracy and highest value in their respective
approaches to loudspeaker design, though they differ significantly in their cost
to you. |
My motto has always been to be "true to the original, as it was recorded". I want to reproduce a recording without adding or subtracting from it either because of the loudspeakers or the room. On this website you find information that allows you to build, to purchase, or to design loudspeakers which exemplify the pursuit of accuracy.
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And then listen to a talk given 30 years later about accurate sound reproduction from two loudspeakers in a living room, to hear and see what more has been learned. |
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My Toneburst Test Signal CD allows you to evaluate your listening room's interaction with your speakers, particularly at low frequencies. The Sound Pictures CD gives you clips from my own recordings that I use to assess the accuracy of my loudspeakers.
Consider a pair of reference earphones that you equalize to your hearing in order to find out what is really on the CD you have been listening to, and what your room and speakers are contributing.
Read about how loudspeakers should radiate sound uniformly and how they should be placed in the room so that they disappear sonically and the room opens up to the recording venue.
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Check out the topics that are listed in the column on the left hand side of this page. I hope that the material presented here will add to your understanding of what is necessary for accurate sound reproduction. Regrettably, much misinformation and outright nonsense has been published to promote certain "high-end" audio products. The power of suggestion works exceedingly well, when listeners do not trust their own hearing. I recommend to re-calibrate yourself frequently. Listen closely to all sorts of non-amplified sounds in order to recognize and remember natural sonic scenes. Without a reality based mental reference it becomes an endless and futile pursuit to listen for differences between speakers and equipment in order to find the least falsification and the closest illusion of live sound. |
Check out the ORION Users Group for the exchange of ideas, for questions about ORION and PLUTO and to make contact with owners.
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