Sony APM-77

Sony APM-77W

April
1 9 8 1 april 1981
1 9 8 5 1985

The APM-77 is the original "affordable" APM loudspeaker : launched after the APM-8 but before both the APM-6 and APM-4.

The 77 sported a slightly grainy grey finish and was thus quite modernistically futuristic ; this was however made of a cheap plastified layer glued on the enclosures... Original and shortlived version.
As the 1980s turned out to be far more conventional than expected, it is the later 77W (W for Wood) that is well remembered : the latter has a quality and thick veneer plus beautifully designed plywood grille frames.

APM drivers are made of an aluminium honeycomb mainframe with ultra-thin aluminium covers - 100x more rigid than paper cones. There's a supplementary layer of very thin damper sheet between the honeycomb and the aluminium covers.
The chassis are all diecast aluminium of the science-fiction-esque kind !

The APM-77 drivers were reused in the later ESPRIT APM-4 and alas suffer the same illness as most of Sony's APMs : the bass foam surrounds rot away. And Sony didn't keep a stock of spares.

However, given the very structure of the APM drivers, the diaphragm doesn't hang loose without surrounds as the piston movement is activated by four coils/pistons and stiffened by a centering cap/rod. So they do function fine with dead or even absent surrounds but look really shabby that way and the acoustic sealing is slightly disrupted.
As for the APM-4, the bass-reflex port is tuned very low in frequency (< 25Hz) so this is practically a sealed enclosure design (which is also why I like them so much).

The 77s provide a very balanced sound : straight, precise and clean up to high output levels with excellent horizontal and vertical dispersion. They are linear but "inviting" speakers, much more so than what the driver's shapes and overall design may imply. However, beware, like the APM-8, they are made to be placed next to the wall(s), with no more space than 3 to 5cm.


It is difficult to imagine today that the APM-77W sold... rather well ! Due to present scarcity asserting some production run is difficult but Sony made and sold a sizeable amount of 77W nevertheless : around 4000 pairs.

The japanese magazine Audio Accessory often used Sony's APM loudspeakers for its reviews, even if more often the smaller ones : APM-55W and APM-33W.
Probably because their bass / mid crossover was set lower than the rather high 700Hz of the 77s (vs. the 600Hz of the APM-4).

The optional but strongly recommended stands are the WS-500 but those of the little SS-G1mkII (WS-E70) fit just as well - same shape, same design.


Like the TA-AX7 and TC-FX1010, it took me 25 years to get a pair of 77W.
I will never ever let them go : to get as excellent music reproduction from 'speakers made today, I'd need to shed a lot more money. And they certainly wouldn't look that surprising.

Sony APM-77, image 1 Sony APM-77, image 2 Sony APM-77, image 3 Sony APM-77, image 4
Sony APM-77 specifications
Title Value
Type : 3-way bass-reflex
non-resonant b/r port
Internal volume : 66L
Frequency response : 28Hz...30Khz (+4 / -8dB ; DIN)
Drivers : 1x 530cm2 bass (= c. 30cm cone)
1x 27cm2 mid (= c. 6cm cone)
1x 7cm2 high (= c. 3cm dome)
Crossover : 700Hz
4,5Khz
Nominal impedance : 6 Ohm
SPL : 90dB /1w /1m
Power handling : 100W (DIN 45500)
Peak power handling : 200W (DIN 45500)
Highs adjustment : 0...-50dB
Mids adjustment : 0...-50dB
Dimensions : 40,5 x 74,5 x 32,5cm
Weight : 32kg
34,5kg (packing carton included)
List price : 150,000¥ (APM-77)
160,000 (APM-77W)
Optional WS-500 stands : 36 x 34 x 32cm (4,5kg each ; 8500¥ /pair)
Optional cables : RK-10S (2x 3m ; 12,000¥)
Features : glass wool + high polymer fiber enclosure damping
OFC wiring for all coils and filter
OFC 400µm boards tweeter & mid networks
direct connection between bass driver and network
Sony APM-77 : 1 topic
(last updated topic shows up first)
  • Sony APM-77W                             (2)last updated by Stoffie - 20/08/2016, 15H17
page online since : february 2007
page updated : march 2010
page type : LGT / KNB
page weight : 649.17 Kb / 269.96 Kb

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