Ode to “foamed” nickel, nonexistent sapphires and the Soviet deputy minister: iconic OTTO SX-P1 in Japan, the USA and the USSR

    One of the most coveted speaker systems for lovers of sound archaic, of those that were mass-produced in the second half of the 20th century, is the OTTO SX-P1 (aka Fisher STE-1200). We can say that there is a whole cult of this acoustics, and its advantages are recognized by both hard-working techies and pathos audiophiles. It is often written that in 2000, these speakers made it to the TOP-20 of the best speakers of all time according to the version of Stereophile (I could not find the journal number, but I believe that this is quite possible).

    These three-way studio monitors, created by the Japanese company SANYO in 1976, contrary to the calculations of marketers, have spread as home acoustics. During the sales, they gained a reputation as one of the most “honest” speaker systems, and the vast majority of those who heard the system note the so-called “Presence effect”, “realistic sound”, as well as the exact localization of apparent sound sources in a wide and deep stereo panorama. Not without fairy tales - this acoustics has become one of the most mythologized audio components in history. Under the cat in detail about the OTTO SX-P1, the history of its creation, myths, reality and the Soviet copy.

    Collection of myths

    To begin with, I will allow myself a couple of mythological paragraphs in which I will collect all the legends and tales about this acoustics that periodically appear in the media.

    In faraway Japan, SANYO engineers decided to create the world's best serial three-way speakers. Thus, in 1976, the OTTO SX-P1 was born, which has ultra-low distortion a thousand times lower than the threshold of human perception.

    It was possible to achieve unique technical characteristics thanks to the foamed metal under the influence of high temperatures, the sapphire coating of the midrange speakers and the use of lasers to create slots in the tweeter head. The super-mega-unique technologies of the past cannot be repeated, and for this reason today they do not produce analogues of unique acoustics. After 10 years in the USSR, they tried to repeat the Japanese miracle and did a terrible, incapable Frankenstein.

    I learned some of the myths from this article , this video , as well as from numerous audio forums where they (myths) have been walking for decades, not for years.

    The video, by the way, is quite suitable for itself, but it was not possible to manage without a few common misconceptions and excessive pathos.

    Reasons, history of creation and co-branding

    I suppose with myths enough. Reality from them is significantly different. In common with reality in the legend, only the year of the beginning of the serial production of 1976 began, and that this speaker really sounded good, having low distortion (but, of course, not less than 1000 times the threshold of human perception).

    In reality, the development of a new speaker system began in order to gain a foothold in the new for the SANYO segment of the western market, namely the segment of studio equipment. If in Japan they were known as a reliable manufacturer, then for export to the USA the company until 1975 produced mainly inexpensive consumer goods. Nobody set the task to create the best speaker in the world, everything was more pragmatic and trivial.

    The speaker system was originally designed for studios, which in the United States almost everywhere used the products of JBL and other "domestic" American manufacturers. It was for the sake of a conservative and finicky studio market that the practical Japanese decided to create something extremely competitive. In the domestic market, they also competed mainly with YAMAHA (in the professional segment) and Technics (in the home audio segment).

    Interestingly, despite the product being quite innovative for its time, at first the Americans were in no hurry to purchase it. SANYO's reputation as a consumer goods office, unable to make devices for the pros, made itself felt. To eliminate prejudice, we went to the unthinkable for a proud Japanese company - co-branding with Fisher. After the export OTTO was renamed the Fisher STE-1200, sales went much livelier. Later, the cunning Japanese bought Fisher with giblets.


    We will begin the story about technologies with a low-frequency diffuser. It is not made of “some kind of foamed metal” (I have not met such a term anywhere except tales about this acoustics). In fact, the material of the low-frequency diffuser is composite, consisting of volume-porous nickel and aluminum foil.

    Such a material was chosen in order to combine the high stiffness of the diffuser, which allowed the dynamics to work in the piston mode and qualitatively new sound absorption characteristics in order to ensure damping of the reflected waves. The technology has put an end to the issue of a compromise between damping and impulse response, solving both problems at once.

    It seems interesting to me how it was possible to obtain porous nickel. The technology was as follows:

    1. Polyurethane foam (aka foam rubber) of a cubic form was processed using a controlled explosion in a special reticulation chamber. As a result, open-cell polyurethane foam was obtained.
    2. Using a hot string, foam was cut into thin plates to produce blanks.
    3. Billets were degreased in chemical baths using trisodium phosphate and washed.
    4. Then these blanks underwent chemical precipitation with tin salts and copper plating.
    5. At the last stage, nickel was applied to the foam rubber using the method of matte galvanic nickel plating, after which the base was burned in a hydrogen furnace and annealed at the same time.

    the structure of the processed foam rubber is almost identical to the structure of the porous metal.

    After this complex process, volume-porous nickel was adhered to the aluminum foil base, and then the composite material was used as a diffuser.

    Sapphire’s foamed nickel structure in midrange is just as much a myth as “foamed metal”. There is no evidence that sapphire crystals were used. In addition to a very rare and expensive decor in an elaborate design, sapphires were not used and are not used for the production of acoustics (nowhere, never, at all, if only because there is no reason).

    Some sources, such as the video above, refer to the “precipitation method”. In fact, this method is not used to cover something with a layer of crystals, but for the production of artificial sapphires and is called the Verneuil Method. The use of a 3-layer diaphragm, which is 80% alumina, was quite enough to achieve the objectives in the midrange range, no sapphires were needed there. This is not to mention the astronomical increase in cost.

    With tweeters, too, not everything is going smoothly. So concentric slots on the corrugation of the tweeter are supposedly made by a laser. However, smart people told me that in the 70s in Japan, probably there were no 50-70 watt lasers. They in the world with similar power at that time could be counted on the fingers.

    In addition, to create such slots with a laser, a coordinate machine was needed to control the cutting, which did not exist at that time, or 10 years after that. And this is not all the problems that would appear when trying to use lasers. In other words, theoretically it was possible, but it would have cost crazy money and made production senseless.

    The answer was simple. As people who participated in copying the legend in the USSR write, the method of electric discharge machining was used for the slits. Those. just a sufficient voltage was applied to form a breakdown, and a discharge in the form of a conducting column with an extremely high temperature burned holes in an aluminum corrugation better than any laser.

    Design and specifications

    Speaker design deserves special attention. The speakers have a fairly large volume - 110 liters, which corresponds to the axiom: good acoustics - great acoustics. " The case had rather thick (30 mm) walls and was made of a special, acoustically calculated chipboard.

    SANYO engineers carefully approached the acoustic design. They made the case phase-linear, dividing it with an acoustic impedance panel (PAS) into two compartments, one of which acts as a resonator, and the second (low-frequency section) is equipped with two phase inverters, the openings of which open to the front panel.

    A characteristic design feature is the absence of turbulent overtones characteristic of almost all phase-inverted speakers. This is due to the small stroke of the speaker even at high volume and the use of PAS.

    In addition to mythologized composite materials, there are many features in the design of the speakers. So the 30-cm woofer was equipped with a 1.4 kg magnet with a flux density of 11,000 gauss. The suspensions (unlike the late Soviet copies) were made of fabric, guaranteeing their durability.

    Filters that received high-quality components deserve high praise. Collectors who own this acoustics note that the parameters of the elements correspond to the nominal values ​​even after 30 years and almost never require replacement. Subsequently, the original filter circuit was completely copied in the Soviet version and adapted to the domestic element base.

    All these technical solutions allowed the system to provide more than competitive technical characteristics:
    • Conical woofer with a diameter of 300 mm made of porous nickel.
    • Mid-range speaker with a rigid dome with a diameter of 67 mm from a composite material based on aluminum oxide.
    • Tweeter - ring tweeter with a diameter of 38 mm from aluminum oxide.
    • Rated impedance: 8 ohms.
    • Rated Power: 100 W (RMS: 150 W).
    • Sensitivity: 93 dB / W / 1m.
    • Frequency Response Range: 35 ~ 35 kHz ± 3 dB.
    • Crossover section frequency: 500 Hz, 5 kHz.
    • Dimensions: Width: 450 mm. Height: 910 mm. Depth: 430 mm. Volume: 110 liters.
    • Mass of one system: 51 kg.

    Soviet clone

    In accordance with an unconfirmed and not refuted legend, deputy. USSR Minister of Medium Engineering Alexander Usanov was an avid music lover. On one of his business trips abroad, he was impressed with the OTTO SX-P1 and returned to the USSR with two sets of this acoustics.

    The official got the idea to give the Soviet people a similar device. A few years later, the Moscow defense NGO “Thorium” was tasked with copying the device brought from the “decaying west”. This legend is very similar to many others. Perhaps because such a story was typical for the USSR, or it was just a beautiful myth.

    There is an opinion that defense enterprises were tasked with developing such equipment solely because the rest were not able to produce anything of any use, but this is not entirely true. Employees of the NGO Thorium recalled that even before the start of Gorbachev’s perestroika, the number of defense orders began to decrease, and budget cuts and civilian devices were developed just to increase the financial efficiency of the organization.

    One of the samples transferred to “Thorium” was disassembled to the screw and carefully studied. As a result, in 2 years, Soviet engineers figured out and were able to repeat almost all the technological processes used to create this acoustics in an NGO.

    The OTTO SX-P1 has been copied almost completely. Only a few decisions were considered not entirely rational. So the Soviet version 100AS-060:

    • did not receive a three-layer composite in the midrange dynamics (they simply limited themselves to alumina);

    • the speakers were equipped with magnets with a lower flux density, which affected the sensitivity;
    • with the same circuitry, the quality of the elements used for the filter was significantly different;
    • they did not begin to develop a special chipboard for the case and limited themselves to the available one, the thickness was also reduced to 29 mm;
    • instead of the impregnated fabric, foam rubber was used to suspend the woofer diffusers, which made them extremely short-lived;
    • alumina was not used for the tweeter, limiting itself to high-temperature pressing food foil, and therefore, at high volume in the high-frequency spectrum, subtle but characteristic metallic sounds can be subjectively distinguished.

    Described, despite these differences, the result exceeded the expectations of the developers. Prototypes had characteristics unattainable for Soviet acoustics:
    • Frequency range: 31.5 - 25000 Hz;
    • Sensitivity: 88 dB;
    • Uneven frequency response of sound pressure in the frequency range 100 - 8000 Hz relative to the average sound pressure level in the range of 50 - 20,000 Hz: ± 4 dB;
    • Orientation at angles to the acoustic axis:
    • in the vertical plane ± 7 °: ± 4 dB;
    • in the horizontal plane ± 25 °: ± 4 dB;
    • Harmonic coefficient in the frequency range:
    • 63 - 1000 Hz (at a sound pressure of 96 dB): 2%;
    • 1000 - 2000 Hz (at a sound pressure of 93 dB): 1.6%;
    • 2000 - 8000 Hz (at a sound pressure of 90 dB): 1.4%;
    • Resistance: 8 Ohms;
    • Minimum impedance value: 6.4 ohms;
    • Nameplate power: 100 W;
    • Weight: 51 kg;
    • Dimensions (HxWxD): 915x455x475 mm.

    Failure to comply with certain technological standards in production reduced fidelity of reproduction and "repeatability" in serial samples. But even in spite of this, the "Electronics 100AC60" could compete with any Soviet counterpart and many Western models.


    The bottom line is that the OTTO SX-P1 is really one of the best examples for its time, in which bold and unusual technical solutions were used that made it possible to solve a lot of complex technical problems.

    Moreover, all the stories about the “boiling” (foaming) of sodium, sapphires and lasers are nothing more than myths that are essentially unnecessary, because acoustics without them is a fairly high-tech product with excellent characteristics.

    The Soviet copy of the Japanese legend was inferior to the latter in a number of characteristics and was made a little simpler. At the same time, the 100AC-060 managed to repeat most of the significant competitive advantages of the OTTO SX-P1, in particular, porous nickel, metal speakers and unique acoustic design, phase-linearity, excellent damping.

    Today, the market and the interests of manufacturers dictate their conditions, people want cheap acoustics, and manufacturers earn more by spending less resources. Profit This leads to the fact that, it would seem, not too complicated for the present, but more expensive technologies remain in the past, giving way to more utilitarian ones. Photo

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