Sony APM-8

The very first ESPRIT unit which launched the ESPRIT brand itself in july 1979, with Masaru Nagami at the helm.

The APM-8 managed to find its way to the cover of the spring '82 issue of Stereo Sound and garner a State of the Art Award as well.

At 1,000,000¥ a pair, sales weren't planned to be massive, but the APM-8 is the one well-remembered flat-membrane loudspeaker. The Pioneer S-F1, Onkyo CP-5000 or Hitachi HS-5000 remain unseen object for the cognoscenti while the prototypes built by Yamaha, Diatone and Kenwood remained... prototypes.

Although terribly expensive and enormous in size, the APM-8 isn't that rare. Myth has it that there were only 16 pairs made but that's myth only : there were at least 400 pairs made.
Many probably were thrown away later in the 1980s due to the nearly irreplaceable rotting surrounds, many probably still sleep in studio backrooms and that makes the surviving APM-8 loudspeakers nearly invisible.


Besides Masaru Nagami, general manager of the ESPRIT division, I guess Keijiro Maeda and Tadashi Higuchi should have been around the APM project as well.

The first finished and marketable APM was the APM-9 but it never got out of Sony's R&D departments and was more like a few test samples among others.
Fully functional prototypes of the APM-8 were shown as early as spring 1978 with the last pre-production samples coming in in september and december 1978 ; the race to finish the production model happened during the 1979 spring.
The APM-9 is located in time at the end of those two last phases and what I call the october 1978 "civilized" sample at the beginning (see Knobber image #17).

From what I can see in my Sony ES Review corporate magazines, the initial development must have taken place around 1976, if not before.

The APM-8 are made to function very close the the back wall of one's room, nominally 2cm away ; it wass also clearly made to be used in a 4-way active-filtered system by bypassing the included filter and using the eight connectors on each speaker.
The tweeter and low-mid drivers are internally connected with reversed phase when used in full-range mode ; in multi-amp mode, all drivers are in-phase. If you find your 8 to lack bass or have it the wrong way, you know where to look first if they have been tampered with or "restored" before.

Sony went an entirely different way a few years later with the Bio-Cellulose membranes used in the SS-A5 Voce series, the massive SS-GR1 (1989, another awarded unit) or the small ES SS-G55ES and G33ES which all used (almost) conventional cones added to Bio-Cellulose tweeters.
Not to mention the ultimate and xxx-rare SS-R10 (1995) which was an... electrostatic !

That doesn't make Sony an incoherent brand but one that looked for different ways to reach for the same goal : each of those ways set in its own coherent timeframe : market, trend and available technology.
Like PCM sound, flat-membrane loudspeakers were all the rage in 1978/1981 and every major brand went for it. Sony was there first.

If I judge APM sound by the kind of music I get from my APM-77W, a properly restored APM-8 must be... quite something.