The Art of Speaker Design. The Art of Speaker Design. This chapter opens with a quick trip through the future, the past, and the challenges of designing speaker systems in the here and now. These challenges can be met in many different ways, resulting in many different schools of speaker design. Due to the limitations of the art, no one school can . At a more detailed level, the designer has to examine the sonic character of different types of direct- radiator driver, and know the advantages and limitations of each type. Even designers who profess an agnostic, specification- driven approach make an esthetic decision when they decide which group of specifications to optimize. At every point, from overall system design to subtle points of cabinet construction, esthetic preference merges invisibly with engineering decisions. The Future. If you relax and take a mental journey to the 2. Century, it is easy to imagine the perfect loudspeaker. It would made of an immense number of tiny point sources that would create a true acoustic wavefront (or soundfield). Resonances due to massive drivers and cabinets would be a thing of the distant past. A host of distortions (harmonic, intermodulation, crossmodulation, frequency, phase, and group delay) would be utterly absent .. Let your imagination roam free .. The primitive 2. 0th Century technologies of telephones, movies, radio, television, hi- fi stereo, and the World Wide Web converge into an apparently simple technology that is transparent and invisible. The Past. Contemporary speakers, for all of their faults, are better than most speakers of the Fifties. The typical enthusiast had to endure University, Jensen, or Electro- Voice 1. A large cutout served as the vent, resulting in boomy, resonant boxes tuned much too high, with a 6 to 1. Welcome to the Harris Tech Audio website! This is the home of BassBox, our famous speaker enclosure design program. We offer two versions: BassBox Pro and BassBox Lite.B peak in the 8. 0 to 1. Hz region. The sound quality was closer to an old neighborhood theatre, or amusement park skating rink, than a modern speaker. The tube electronics helped sweeten much of the coarseness, but they couldn't rescue the really bad loudspeakers of the day. True, the first- generation Quad, the RCA LC- 1. A, the Tannoy, and the Lowther compare well with modern systems .. The classic speakers cost as much as a new Volkswagen or the down payment on a house! Peering through the looking- glass of time, we can see that the old designers had no consistent way of modeling or predicting the bass response, and the materials available for tweeters were very poor by modern standards. Today, accurate, design- by- the- numbers bass is taken for granted, and modern tweeters really are superb. Where modern systems fall down is midrange performance, which doesn’t lend itself to the computer design tools that are so convenient in the bass and treble range. The sparkle and dynamism of the best classic speakers is in the midrange, the most important, and yet the most challenging, part of the entire spectrum. Progress in the midrange region has been slow for many reasons. The ear reaches its peak sensitivity this region, drivers are operating at the edge of their frequency range, and the designer has to contend with spectral flatness, polar response, IM distortion, impulse response, cabinet energy storage, diffraction, and crossover polar characteristics all at once. By the late Sixties, the big 1. The new speakers had 8. By modern standards, they were dull, dull, dull, with mediocre imaging and coarse, low- resolution sound. This was thanks to the minimal crossover, undamped standing- waves in the box, not using a mirror- imaged driver layout, and diffraction problems with the decorative edges of the box, grill frames, and heavy, non- removable grill cloth. Although the new bookshelf speakers measured flatter using the simple measurement techniques of the day, the wonderful sparkle and verve of the best Fifties designs was lost. It wouldn’t be until the late Eighties, with re- introduction of higher efficiencies, new cone materials, and more powerful measurement systems, that the directness and immediacy of the classics would be regained. Between the late Sixties and late Eighties, . Progressive improvements in speaker design over the decades now reveal the actual sonic quality of these first- generation transistor amplifiers as badly flawed, while the . Design and consultation in electro-acoustics. Fundamental concepts of sound reproduction in rooms. Detailed design information for DIY construction of a subwoofer and. Eminence Designer Software. Eminence Designer is a state-of-the-art loudspeaker enclosure design program for PCs. It can calculate a box design that will bring out. Here's a partial list of the problems faced by contemporary designers. The virtual image is unstable with respect to listener position, spectral energy distribution, and room characteristics. Even a simple central mono image has been shown to suffer from deep comb- filter cancellation nulls between 1 k. Hz and 4 k. Hz, which is why a solo vocalist sounds different coming from a single mono speaker and a conventional stereo pair. I have found approximately a dozen freeware and shareware speaker design CAD programs which are of great use to the. This CAD software program may. Speaker Design, free speaker design software downloads. File Name: design-icons.zip; Author: Aha-soft; License: Demo ($129.00) File Size: 4.41 Mb. Design software for solving the required calculations for building bandpass, sealed and vented speaker and subwoofer box designs. Build, plan and design your own. Shareware programs, on the other hand. A program to design speaker boxes for cars dual order bandpass. Psychoacoustic research indicates that 2- channel signal sources require a minimum of 3 loudspeakers to faithfully re- create the tonal quality of centrally located sound sources, such as vocalists. Driver damping techniques usually improve spectral characteristics (the frequency response curve looks better as a result) but do not provide much improvement for the underlying breakup modes, so the distortions may actually be spread over a much broader frequency range. The narrowband nature of resonant distortions in loudspeakers is why a single- frequency THD or IM measurement is useless; it takes an expensive tracking- generator type of measuring system in order to create a usable frequency vs. These graphs usually show quite different frequency spectra for the 2nd and 3rd harmonics, as well as curves as rough as undersea topographic maps. The driver diaphragm needs to have a density equal to air and absolutely uniform acceleration over the entire surface at all frequencies if you want to remove all resonant distortions. We are nowhere close to meeting this criterion. As a result, all speakers have tonal colorations ranging from subtle to gross, with some types of colorations present at all times, and other types of colorations appearing only at high or low levels. A reviewer's preferences in music can easily mask the presence of these problems if they listen to music with a relatively simple spectral structure. The unwanted mechanical energy must be quickly discharged in two ways: rigid, low- loss mechanical links to the earth itself (a rigid path from the magnet to stand to floor to ground), and also dissipated as heat energy in high- loss, amorphous materials such as lead, sand, sorbothane, etc. The energy that is not removed is re- radiated as spurious noise from every single mechanical part of the speaker and cabinet, each of which has its own individual resonant signature. In any real speaker system, regardless of operating principle, there are hundreds of standing- wave resonances at any one time, which are released over times ranging from milliseconds to several seconds. These resonances continually overlay the actual structure of the music and alter the tonal color, distort and mask the reverberent qualities of the original recording, and flatten and blur the stereo image. In speakers that measure . This is also the reason that 1/3 octave pink- noise measurement techniques have fallen out of favor, being replaced by much more revealing techniques such as TDS, FFT, MLS, and others. Diffraction, which occurs at every sharp cabinet boundary, creates delayed, reverse- phase phantom sources that interfere with the direct sound from the actual driver. These secondary phantom images create significant ripples in the midrange response (up to 6 d. B) and create delayed sounds which disrupt the timing cues necessary to perceive stereo images. These dispersion problems are audible as room- dependent colorations, coarse midrange, diffuse stereo, and a . There are other problems, not as severe, but still quite audible to a skilled listener. These problems occur in all loudspeaker types - dynamic direct radiator, horns, ribbons, electromagnetic planar, electrostatic planar, you name it. They all have lots of harmonic and IM distortion concentrated at certain frequencies, they all store and release significant amounts of resonant energy, and they all have frequency- dependent dispersion further degraded by diffractive re- radiation. This is why I treat claims of . Does the new wonder technology address even one of the serious flaws cited above? The real story is year after year of a steady and progressive improvement in materials technology coupled with big steps in measurement technology and computer modeling. Where Do You Start? With this background, the most important question of all becomes quite simple: What kind of sound do you like? People actually hear the world in quite different ways, and different people assign importance to different qualities of sound. Some audiophiles value tone above all else, treasuring the sound of their favorite instruments or voices; some like a sense of immediacy, directness, and emotional impact; some like the sensation of an immense 3. D space; and others like a see- through transparency, a palpable . For one thing, the materials to build anything of the sort simply don’t exist. If you have, you’d better forget about speakers and talk to the Department of Energy first.) Major Schools of Speaker Design. Since all designers are forced to choose on a subjective (or marketing) basis, there is no single . If anyone tells you that, it might be interesting to investigate their personal beliefs a little further and see if they worship at a church of religious fundamentalism or the much larger church of ? Well, I’m certainly not an audio- fundamentalist, or any other kind of fundamentalist! I pay attention to spectral flatness, minimizing IM and FM distortion, very low energy storage, and low diffraction. Of course, these objective measurements are only a means to an end. More importantly, I seek an elusive quality I call . For those of you who have never had this experience, I can tell you it really does happen, but only about as often as seeing a perfect double rainbow.
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