Ancient extremes

August 23, 2021
 by Paul McGowan

I find it ironic that at the end of our audio chain lies some really ancient technology based primarily on magnetism.

Loudspeakers, with few exceptions, are moving coils of wire in magnetic fields: technology invented hundreds of years ago by names like Michael Faraday, Nikola Tesla, and Thomas Edison.

The system that powers those ancient technology speakers is state-of-the-art: microscopic bits of silicon.

Of course, there are exceptions: electrostatic, and the rare ionized gas oddities, but for the most part, we’re using magnets and copper to move air.

This effective blend of old and new is fascinating to me.

Perhaps it’s accurate to suggest it’s on occasion difficult to improve on a good idea.

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48 comments on “Ancient extremes”

  1. Far more interesting is the vinyl cartridge, which uses a magnet moving between electric coils (or vice versa) to generate an electric current. Michael Faraday would have recognised this instantly.

    The discovery of electromagnetism (it was not invented), the ability to move things with electricity and magnets, was certainly handy, else our stereos would probably be powered by steam.

    1. However actual vinyl cartridge technologies feature optical cartridges- no heavy moving coils or moving magnets/irons anymore. Not to mention the laser turntable from ELP Corp, Japan. 🙂 If the goal of hifi-stereo is to just exactly reproduced the recorded signal captured by a thin light membrane of the microphone used then most loudspeaker designs are inherently most far from reaching this goal. Only a coaxial driver-design might come closer to this goal but inherently fighting Doppler effects. Still a lot to do for designers of hifi (!) loudspeakers.

  2. Hmm…I’m trying to imagine a steam powered stylus/cartridge/turntable.
    (I’ll always like the one that Fred Flintstone had)

    It still amazes me too Paul; especially when you consider microphone to tape to
    master-cut to vinyl pressing to cartridge to magnet/coil driver…it’s f#@king amazing.
    Like when I watch a 183.5 (Boeing 747) ton aeroplane fly over my head
    …this does not compute.
    Ain’t physics just wild!

    Retro album for today: ‘Pontiac’ – Lyle Lovett (1987)

    1. We humans are so fickle about things we cannot see, like electromagnetic waves and pressure differences over an aerofoil. A punch in the face, we can see that and are rather less impressed.

      1. Yeah, I know…I can understand mathematically the air pressure difference above & below an aerofoil, however when all that tonnage flies over me, the cogs in my brain seize-up, just for a second; it’s involuntary.
        I haven’t had a punch in the face since the mid ’70s…I’ve almost forgotten what it feels like.

      2. This is a delayed burst reply, I did not read Paul’s Post and comments yesterday for various and sundry reasons particular to my little sliver of the space-time continuum, “but wha’ o’ that?”

        I read an anecdote in comments to Rick Beato’s impromptu eulogy for Charlie Watts earlier today:

        A drunken Mick Jagger gave Charlie a bell (is that the British phrase?) and demanded to know ‘Where’s my f***in’ drummer?’ Charlie got dressed in a nice suit and tie, gave his leather shoes a quick but serviceable polish, and went over to the recording studio. He located Mick, punched him in the face, and provided this bit of enlightenment: ‘I’m not your f***in’ drummer. You’re my f***ing singer.’

        Or words to that effect. Apocryphal, but a good anecdote.

        1. To give someone a bell is to telephone them. It either comes from the fact that telephones used to have a bell that rang, or the fact that the telephone was patented by Alexander Graham Bell. Take your pick. Alternatives for telephone are ‘blower’ and ‘dog and bone’.

    2. I used to live very close to Andrews Air Force Base (now Joint Base Andrews), and regularly saw those humongous cargo jets so gracefully take off and land. That, to me, is like seeing a 441 lb (200kg) man run the 100m dash in 9.00 seconds as gracefully as a jaguar.

  3. It is fascinating and we hold on to many technological staples with in our industry. Take for example, Cars! The Internal Combustion Engine is well over 100 years old now and like audio we’ve taken the foundation of the internal combustion engine and have gone through many extremes with it. 🙂

    Great post and good morning everyone.

        1. Has your friend had you over to demonstrate any of the Tesla Easter eggs or holiday downloads? While having nothing to do with the performance of the car some of them seem quite fun to watch (at least on the You Tube channels).

  4. What gets me is that we never figured out how to fly for over 1,900 years… Then 50 years after our first flight we were on the moon.
    So what is just around the corner for speaker tech? Something room temperature semiconductor-ish perhaps, or maybe some sort of chemical expansion process… Akin to the piezoelectric effect, but on steroids. The stuff of dreams… Hopefully I’m around to see and hear it!

  5. According to Wikipedia:

    The dynamic speaker was invented in 1925 by Edward W. Kellogg and Chester W. Rice issued as US Patent 1,707,570. Apr 2, 1929.

        1. Good morning Tarheelneil!
          The invention of the electronic loud speaker, dates back to the 1860’s, and 1870’s.
          You wanted me to state my saurse, well, here it is below this comment.

          The first loudspeakers

          Modern electric loudspeakers had their origins in radio and telephone technology. The first simple type of electronic loudspeaker was developed by Johann Philipp Reis in 1861. Reis was a teacher at Friedrichsdorf, Germany and he was a self-taught inventor. He installed it on his telephone. It was crudely able to reproduce clear tones, but it can also reproduce muffled speech after a few revisions.

          In 1876, Alexander Graham Bell, the inventor of the telephone, tried to produce a speaker based on Reis’ work. This time, there wasn’t enough knowledge yet about physics and material engineering to successfully invent an electrodynamic loudspeaker. The need to amplify sounds did help spur the development of amplifiers.

          The idea of an electromagnetic coil-driven speaker was introduced in 1877 by Werner Von Siemens, the founder of the electrical and telecommunications company Siemens. Siemens used to input signals of DC transients and telegraphic signals. This wasn’t a successful speaker, but due to his experiments, he theorized that amplification could be eventually done.

          At the same time, Thomas Edison and Nikola Tesla were experimenting with similar devices. Edison has issued a British patent for a system using compressed air for an amplifying mechanism for his phonographs. However, he settled for the familiar metal horn driven by a membrane attached to a stylus.

          Inventors relied on horns for amplifications back then. Thomas Edison, Magnavox and the Victor Talking Machine Company (maker of the Victrola wind-up phonographs) all developed advanced and well-performing horns. The problem is, their horns don’t amplify the sound very much.

          In 1898, Horace Short gained a patent for a loudspeaker that is driven by compressed air. He sold the rights to Charles Parsons.

          Various inventors and companies played with the idea of the electrodynamic loudspeaker. Companies like Pathé and the Victor Talking Machine Company produced record players using compressed air speakers, but those are significantly limited by poor, distorted sounds.

          Moving coil loudspeakers

          The first experimental moving coil loudspeaker was developed by Oliver Lodge in 1898. Later, Peter L. Jensen and Edwin Pridham manufactured practical moving coil loudspeakers in 1915. Like the previous loudspeakers, they used horns to amplify the sound produced by a small diaphragm. Jensen and Pridham were denied patents, so they changed their target market to radios and public address systems. They developed their own company called Magnavox, and it became a success.

          The moving coil principle was patented in 1924 by Chester W. Rice of General Electric and Edward W. Kellog of AT&T. The two were able to adjust the properties of coils until they lowered the frequency at which the cone’s radiation impedance became uniform, thus replicating noise. Previous attempts to make the loudspeaker produced unacceptable muffled sounds, but Rice and Kellogg solved the problems that led to nice, crisp audio. Their prototype had a more diverse dynamic range in frequencies, making it better than the horn. It can also increase in loudness. After several years, they perfected the product and called it the Radiola Loudspeaker #104. It was sold in 1926 for $250 and was produced under the Radio Corporation of America (RCA).

          The first real loudspeakers

          The electric devices used to create sound in telephone and in radio earphones were called receivers or reproducers. During the 1880s to 1890s, inventors would occasionally think up of ways to use the telephone for a larger audience. Some simply attached a large horn to a telephone receiver to make a “loudspeaking telephone.” This was where the term loudspeaker originated.

          When Bell Labs introduced the first electronic vacuum tube amplifier in 1916, the true loudspeaker became possible. This kind of speaker was fine for public address systems offered in 1921, but the sound quality wasn’t good enough for motion pictures just yet.

          In 1924, the first commercial electric loudspeaker was introduced. It used an electromagnet to drive a large paper cone that reproduced the original sound, as it vibrated under the influence of the amplified signal. This was based on some versions of the early telephones from the Siemens Company during the 1880s.

          Meanwhile, radio created another branch of loudspeaker technology. In 1924, Brunswick Balke Collender Company introduced the first all-electric home phonograph, in cooperation with RCA, Westinghouse, and General Electric. This was the first home phonograph that was called a “dynamic” loudspeaker, which was similar to the kind still used today.

          Ribbon loudspeakers

          Around 1924, Walter H. Schottky invented the first ribbon loudspeaker together with Dr. Erwin Gerlach. These loudspeakers used diodes.

          Later on in the 1930s, ribbon loudspeakers began to combine drivers in order to make amplification better. In 1937, James Bullough Lansing, Douglas Shearer, and John Kenneth Hilliard invented the “Shearer Horn System for Theaters.” This system was introduced to the film industry by Metro-Goldwyn Mayer. It used 15” low-frequency drivers, a crossover network and a single multi-cellular horn with two compression drivers that provide high frequency.

          In 1939, a very large public address system was mounted on a tower at Flushing Meadows during the New York World’s Fair. It was designed by Rudy Bozak, who worked as a chief engineer for Cinaudagraph.

          Duplex drivers

          In 1943, Altec Lansing introduced the 604, which was the famous Duplex driver that dramatically improved sound quality and performance. Altec’s “Voice of the Theatre” loudspeaker system hit the market in 1945, and it offered better clarity and coherence at high volumes, which was important in movie theaters. It was immediately tested by the Academy of Motion Picture Arts and Sciences and made it film house industry standard in 1955. Until now, this loudspeaker design is still used.

          Acoustic suspension

          The principle of acoustic suspension for loudspeakers was first developed by Edgar Villchur in 1954. This allowed better bass response than previous drivers mounted in smaller cabinets. This technology was important during the transition to stereo recording and production. Villchur and Henry Kloss formed the Acoustic Research Company to manufacture and sell speaker systems with acoustic suspension. Today you have many choices of the best center channel speakers for home theater available that can provide you great sound quality and bass.

          Subsequently, this led to continuous developments in speaker enclosure design for audio quality improvements. The most notable developments in modern dynamic drivers are the improved cone materials, improved permanent magnet materials, the addition of higher-temperature adhesives, improved measurement techniques, and computer-generated designs.

          And also, there is a video of the first ever electronic hornless speaker on You Tube too as well.

          1. Prior to the Rice/Kellogg invention, they did not have “loudspeakers’. They had speakers, but NOT loudspeakers. Also, the Rice/Kellogg speaker was not patented in 1924. They did not apply for a patent until April 1, 1925, and the patent was not issued until June 30, 1931.

  6. Good morning everyone!
    Lets take that speaker, and take a much closer look at it!
    Sure today, we’re using earth magnets in our speakers.
    That is, most of us are, anyway.
    What I’m about to say here, mite show up some people’s ages.
    But on the other hand, some mite scratch their heads and ask, “how does a 49 year old blind man know about this kind of stuff?”
    What I do know, goes way beyond my years.
    Long before earth magnets, speakers had electro magnets in them.
    Those really tall speakers at movy theaters in the thirties, those magnets were powered with large rectifiers.
    Without all of that DC voltage and currant, no magnet, no sound.
    Radios used those coils as apart of the power supply Cirket.
    In other words, a choke.
    I don’t remember what website I read this on some 15 years ago, but it said, “electro magnetic speakers, made the best subwoofers.”
    How is this for some ancient extremes for you?

  7. Paul, Are you kidding me, ancient technology? Without the discovery of electricity and magnetism ( E&M ) and the brilliant efforts of people like Ampere, Faraday, Tesla and Maxwell ( to name just a few ) to completely understand E&M there would be no modern technology today including the so called state-of-the-art ( SOTA ) silicon chips that you eluded to in amps ( consumer audio electronics does not use SOTA silicon technology but rather much less expensive down level silicon technology ). However, many dynamic speakers made today do use SOTA material science technology in everything from their enclosures to their speaker cones.

  8. Well, some say the best systems still consist of vinyl+tubes+horns. Some High end show rooms like from Western Electric with nearly complete technology from the 60’s are still considered as among the best of the shows.

    Astonishing from this perspective, what progress audio has (not) made since 60 years.

  9. Talking about speakers…
    Before we come to the Star Trek scenario “telepathically music as the next stage of wireless”, right now maybe WiSA is a more realistic idea as a (much better) replacement of bluetooth.

  10. Human beings are the the most ancient of them all. So are they extreme ? It does not matter as far as the time scale is concerned. Anything that works and works well is as modern as can be. Anything that is a step backwards no matter how fascinating and impressive it may be belongs on the heap of discarded discoveries and is that heap high! Regards.

  11. Paul have you ever heard of actuator powered speakers using ceiling tile, fiberboard, plywood, polystyrene and other exotic sheet panels as the speaker? This guy shows how to build them, he tests them with a frequency sweep, and then he plays music at the end of the video. Cheap to make. They have no enclosures, coils, spiders, surrounds or magnets. Just actuators and the square panels. Just hang them from the ceiling. I’m not sure if these are full range or if they need subwoofers but he doesn’t say they do. Could be full range speakers with no crossovers. He claims these are the best speakers in the world.

    1. I have to admit they wouldn’t pass the wife approval test…lol. Better have a dedicated room or man cave. Maybe the garage or a large basement with tall ceilings.

          1. Yep Phil I highly recommend his videos. I watched these two videos I posted a few times and I learned something each time I watched them. He’s very knowledgeable and an expert on speakers. He’s not your average do it your self-er.

    2. Yup. I actually have one installed in my living room ceiling using drywall as the membrane. It’s definitely invisible. I challenge people to locate the speakers. But great sound? No. Not even close. I’d give it a good to acceptable.

      1. The sound likely changes based on how they are constructed and positioned in the room. Having only one installed as part of your ceiling drywall might not sound that great. I don’t think even a single conventional speaker built into your ceiling would sound that good. The guy in the video didn’t recommend drywall as material nor use his entire or even part of the ceiling in the listening room as the membrane. He had them cut into sizes and hung from the ceiling in stereo pairs facing the listening chair the same as conventional speakers.

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