Banner
    Wave Field Synthesis Gives Us Flat Loudspeakers With Big Cabinet Sound
    By Hank Campbell | September 4th 2009 11:06 AM | 11 comments | Print | E-mail | Track Comments
    About Hank

    I'm the founder of Science 2.0® and co-author of "Science Left Behind".

    A wise man once said Darwin had the greatest idea anyone...

    View Hank's Profile
    Flat-panel televisions are nothing new.   I think even my father has one in his toolshed by now.  But legitimate flat-panel loudspeakers are harder to come by.    

    There are single-speaker surround sound systems, and those are admirable, but speakers, unlike today's televisions, require a great deal of old-fashioned physics, analog-style, because that's how sound reaches our ears - so flat panel ones, though a terrific concept in size, haven't been great in practice.   

    If you're suffering from 7.1 channel space overload, there may be good news.   Flat-panel speakers, which don't work very well if actually placed on the walls (which means you don't have a lot of space savings) have gotten a boost from scientists at the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau, Germany and Sennheiser.

    They say their new technology is ultra-flat but still resonant nevertheless.   So you'll still need 8 of them, but at least they won't take over your room.  Because they can blend into the surroundings, they can be arranged in better arrays than may be possible now and despite their small size, they can reproduce a frequency range from 100 hertz to 20 kilohertz, according to Dr. Sandra Brix from IDMT.  "This new generation offers tonal balance and acoustic pressure at a level that will even allow the use in the professional movie or concert segment in the future."

    flat-panel speakers
    Bigger speakers, bigger sound -- this is the music lover's creed. Flat panel loudspeakers offer an alternative to those who would rather not or cannot clutter up their homes with speakers. These speakers can be integrated inconspicuously on walls or in furniture.  Credit: Fraunhofer IDMT

    They say their their flat panel loudspeakers achieve response characteristics other speakers can only get if placed a distance from a wall.

    Using wave field synthesis, some audio systems are capable of producing terrific sound - having a flat panel speaker system to go with it means we could get rid of them as eyesores and instead have them integrated into the decoration - like as part of a picture.












    Credit: www.holophony.net (seriously, go read it - you won't find a better explanation of wave field synthesis)

    Sign me up.  I just redid the A/V system in my den and it's basically unfinished because my choice is either fishing cable through the walls or dealing with bulky wireless speakers everywhere;  a good flat-panel speaker set would at least save me from patching up walls.

    Comments

    Hi,

    I have seen many hits from this page on my holophony.net site.

    Thank you for interest, possibly anyone can help for correct the misstakes in my english translation. If any questions regarding the described procedure, dont hesitate.

    Kind regards from Germany
    Helmut

    Hank
    Hi Helmut,

    To a science audience, grammar does not matter much.   You have the best site on the basics of future spatial reproduction I have seen in a long time so I am glad you got some attention.
    Want more no-nonsense, independent science? Buy Science Left Behind
    Hello Hank

    Thank you for this rating, but your readers should consider, the Holophony net site isn’t the site from the mentioned Fraunhofer scientific institute, but only the private site from any unknown sound engineer.
    The described holophony procedure, which merge together the recording room and playback room acoustics in common system, isn’t realised in practise until. I cannot find e partner for my patented procedure because of the huge effort.

    Regards Helmut

    Mr. Campbell, your writing is incoherent. What are sentences such as

    "There are single-speaker surround sound systems, and those are admirable, but speakers, unlike today's televisions, require a great deal of old-fashioned physics, analog-style, because that's how sound reaches our ears -- so flat panel ones, though a terrific concept in size, haven't been great in practice."
    and
    "They say their new technology is ultra-flat but still resonant nevertheless. So you'll still need 8 of them, but at least they won't take over your room."
    and
    "...legitimate flat-panel loudspeakers are harder to come by."

    supposed to mean? You've never seen QUAD or Apogee or Magneplanar or Martin-Logan speakers? In what way are they "illegitimate"?

    This piece is a mess. I have a (very) rough idea of what you're trying to say, but I don't have the time to edit your writing. You need to learn how to put down on paper what you actually mean to say. (I'm a degreed EE and a professional technical writer who's reviewed audio equipment for Stereophile and other magazines.)

    Hank
    Hi William,

    Resonance means it will oscillate at some frequencies ( that means it will move back and forth, up and down, etc.) better.

    Since you are an audiophile maybe you feel like because the technologies you mentioned are better than some others today, they are actually good.   They are not.   I certainly admire the clever digitial processing in single-speaker surround sound, for example, the same way I admire MP3s - that doesn't mean it is good sound compared to older technology alternatives.  Maybe you like $100 Monster cables too, I know a lot of people do and they insist they can hear the difference(*) but I can't.

    In that same light, flat-panel speakers that require intrusion into the room are not any better than full-sized ones.   This article is about technology that claims it will let the speakers be integrated into the surroundings without the quality impact of burying cabinets in walls.    So you can still get the quality sound of multiple speakers but the space savings of flat panel.

    (*)  I don't discount the possibility even though a spectrum analyzer will show a negligible difference.   The analogy I often use to explain the subtle is that when Joe DiMaggio visited the Louisville Slugger factory to do PR for new baseball bats made with their ultra-accurate machines and they joked with him and asked which one he preferred he replied, 'the lighter one.'   They laughed because the bats were all the same but he was not kidding so they weighed a sample and he had been able to discern the one that was a few grams lighter.

    Likewise, guitarist Eric Johnson says he can hear the difference in tone due to the batteries he uses in his switch and I am certain someone, somewhere, has mapped data to that toplogy to affirm it, just like marketing companies at speaker manufacturers do.   That just doesn't make it good science.
    Want more no-nonsense, independent science? Buy Science Left Behind
    Hi, William,

    you wrote:
    "You've never seen QUAD or Apogee or Magneplanar or Martin-Logan speakers? In what way are they "illegitimate"?"

    That’s a matter of view. One of your honoured colleagues, Barry Wills wrote in Audio 08/94:
    "Tonal accuracy is the best that can be hoped for in a traditional audio system; true spatial accuracy will never happen. Audio products should come bearing this disclaimer:
    „WARNING: IMAGE PRESENTED IS LESS THAN LIFELIKE!"

    All the expensive loudspeakers you mentioned possibly able for produce the perfect signal, but from wrong directions. The concert Hall reflections aren’t originate from two or 5.1 directions. Over and above Phantom source based reproduction- unlike the Wave Field Synthesis principle - depended from psychoacoustic effects. You cannot hold your ear at the sound source; neither walking around, as the wave field principle offers.
    In that respect the described flat loudspeakers a huge step in the true spatial audio direction. It overcomes the limitation of the principle to the horizontal plane of the listener. Thus is important publishing such results of the science, also if the review of some remaining resonances or its cables of subordinate matter.

    Regards Helmut

    There's a wonderful scene in "Born Yesterday" where William Holden asks Judy Holliday what she thought of the essay he gave her to read. She says she didn't understand it, and reads what is to her the incomprehensible opening paragraph. Holden then explains what it means in simple, direct language. She reponds "Well, if that's what you meant -- why didn't you say it?" This is a wonderful slap at "hifalutin" Latinate language I try to keep in mind when writing.

    I don't think you have much understanding of acoustic or electronic technology. You certainly don't know how to organize what you write. If "This article is about technology that claims it will let the speakers be integrated into the surroundings without the quality impact of burying cabinets in walls." -- then (to quote Ms. Holliday) -- why didn't you say so? That should have been your topic sentence, and the rest of the piece should have developed from it. This isn't rocket science -- it's Writing 101. You need to learn how to express yourself so that other people will understand you. You don't.

    These are my final comments. I'm not going to beat this into the ground. If you'd like to discuss it further, please contact me directly. We can talk on the phone if you wish.

    Hank
    Hi William, there isn't much point to critiques of style.  You are a technical writer and an engineer so, to paraphrase the guy who started Black&Decker, if your only tool is a hammer you tend to see every problem as a nail.  

    The obvious solution, if your concern is a positive one regarding proper education of people regarding acoustics, is to write articles on the subject and put them here.   The negative solution is to simply snipe people who actually do something (and then rationalize it as 'constructive') while engaging in rather silly slurs like "I don't think you have much understanding of acoustic or electronic technology" - silly, since you have no idea of my background and other than smarmy jibes haven't actually demonstrated you know anything at all, gratuitous product endorsements aside. 


    Want more no-nonsense, independent science? Buy Science Left Behind
    There isn’t really clear in the Fraunhofer publication regarding the Wave field synthesis flat speaker, which advantages caused by such loudspeaker alignments. Let my try to describe it:

    The loudspeaker field contains a number of dynamic miniature loudspeakers. Each of it is differently steer able in time by calculated delay. In the lower frequency range, all Diaphragm work together, see that graphic for 440 Hz:
    http://www.syntheticwave.de/WFS-Holophony_clip_image002.jpg
    That causing proper load resistance adoption regarding the air, which cannot draw aside simply as by single loudspeakers, because the neighbouring speaker produce the same pressure on the same time. That better resistance adoption cause better efficiency, very low membrane excursion are need for sufficient sound pressure.
    On the other hand the wave field synthesis curves the radiated wave front. By that reason the signal isn’t decreasing in the upper range besides the axis. The resulting loudspeaker isn’t a conventionally loudspeaker anymore, more comparable the "acoustic curtain "solution.
    That principle will offer unimagined possibilities in the next years, because in the near field of such large resulting diaphragm the disturbing influence of the playback room acoustics is shrinking.

    Regards H.

    Hi Hank,
    the linked page improved in translation in the last weeks. An Englishman, lives in Italy, was helping for translate correctly. The side considerably enlarged now and really readable, as far I can translate. :)
    My analytics says, your site is one of the most active traffic sources, still. Thanks for linking again.

    Regards Helmut

    Hank
    Excellent!  If there is one thing our science audience likes, it's applied physics related to accurate spatial reproduction.   :)

    That culture may change in the future.  Try as I might, the current generation are enchanted with .mp3 quality and the best speakers in the world can't make those sound good.
    Want more no-nonsense, independent science? Buy Science Left Behind