OTTO SX-P1 (1976) | Porous Metal

 

Otto (Orthophonic Transistorized Technical Operation) was a brand name used by Sanyo for the Japanese market. The SX-P1 was introduced at the Internatinal Exhibition held in Osaka in 1976 and it received the highest award. At that time, various manufacturers were competing with each other by releasing large, powerful speaker systems priced at around 130,000 yen. There was a lineup of powerful loudspeakers such as Sony's SS-G7, Sansui's SP-G300, and Onkyo's Scepter 10. Among them, Sanyo Electric, which was working hard under the OTTO brand at the time, released the SX-P1. The biggest feature of the SX-P1 was the woofer unit. It was a 30cm diameter cone woofer that used a metal diaphragm called a "porous metal cone." This "porous metal cone" was made by foaming nickel material, then gluing 20μ aluminum foil to the inside, and molding the whole into a cone shape. It achieved high rigidity and sound speed that only metal can provide, and the foaming gave it a sufficiently low Q value comparable to that of a paper cone, achieving excellent characteristics as a diaphragm. It was driven by a large ferrite magnet with a diameter of 156 mm and a weight of 1.4 kg, with a high magnetic flux density of 11,000 gauss, which aimed for low distortion. This woofer was also sold as a standalone unit as the ASX-1 (35,000 yen). The squawker was equipped with a 67mm diameter dome-type unit that used a newly developed 50μ thick three-layer diaphragm made of pure aluminum with 80% alumina on both sides. The tweeter was equipped with a ring-type unit that used a 30μ thick ultra-lightweight 6mm wide ring-structure diaphragm made of hard aluminum. The diaphragm itself was ultra-lightweight at 0.06g, and the V-shaped ring structure had the advantage that the width from the driving point of the voice coil to the edge was narrow, making it less likely to cause split vibration. As mentioned above, from the woofer to the tweeter , it was composed of metal diaphragm units. The cabinet itself was an elaborate one with an ebony veneer finish, and the woofer baffle was as thick as 80 mm. The total weight of the system was 51 kg. The export version was sold as Fisher STE 1200. There was even a Soviet copy of this loudspeaker, the Elektronika 100AC-060.

Specifications:

3-way bass reflex system

Woofer: 30cm diameter, uni-cone type (porous metal cone)

Midrange: 67mm diameter, hard-dome type (oxidized aluminum dome)

Tweeter: 38mm diameter, ring type

Rated input: 100W (200W peak)

Output level: 93db/1m

Frequency range: 25-35.000Hz

Dimensions (WxHxD): 450x910x430mm

Weight: 51kg

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