How Sony's
APM Technology Works
What are the
major design features of Sony's Accurate Pistonic Motion speakers? One key
characteristic is the use of flat drivers. Flat diaphragms have a major
advantage over traditional cone-shaped drivers.
In cone-shaped drivers, the outputs from opposing surfaces of the
speaker cone interfere with each other, causing inaccurate frequency response.
This is known as the "cavity effect", and it's an inherent
abnormality of the cone shape design. Beacuse flat diaphragms like the APM
driver are not prone to this type of distortion, you hear a speaker with more
linear frequency response.
Honeycomb
Construction with Four-point Drive.
To ensure
that these compact drivers won't lose their shape when presented with powerful
sonic modulations, Sony APM drivers feature an innovative aluminum honeycomb
design permits the APM drivers to resist bending - a major cause of distortion
in typical paper drivers. Yet the aluminum honeycomb is light in weight for
superb transient response.
For these
reasons, several speaker manufactures use aluminum honeycomb construction.
However, only Sony uses square diaphragms and four-point drive to further
eliminate potential nodes of vibration. In this way, distortion is reduced to
the vanishing point.
With all the
impressive technology built into the ES Series, it would be a shame to spoil
the final enjoyment of the music by using a loudspeaker incapable of matching
the system's sonic performance. Yet, that's exactly what would happen with many
of the most popular spaekers on the marked today. Very few of them are designed
to handle the extremely wide dynamic range that's an important part of PCM,
Compact Disc, and beta Hi-FI sound. And almost none can reproduce the full
spectrum of the audio frequencies without severe inaccuracies and distortion.
Even something as fundamental as clean, uncolored bass response is beyond the
capabilities of most speakers.
That's way
Sony includes the APM-33W Accurate Pistonic Mption (AMP) loudspeakers as an
integral part of the ES series system. They are uniquely qualified to deliver
all the exciting sonic benefits that are a part of Sony's advanced
technologies.
Reproducing
the particular Attributes of Digital-quality Audio
The APM-33W
speakers combine remarkable efficiency and impressive power handling capacity
(up to 160 watts) with extended bass response and linear, transparent frequency
characteristics. The result is the ability to match the dynamic range of the
PCM disgital recordeer, the Compact Disc player, and Beta HiFi videocasssette
deck without distortion or overload.
And the low
frequency output of the APM-33W is smooth and powerful. This characteristic is
especially surprising when you consider the dimensions and appearance of the
speaker enclosures - they're small and attractive enough for almost any
installation in almost any room.
The Final
Analysis
What do
these adbanced APM speakers sound like? Their response is clean,
distortion-free, and highly accurate. Their frequency range is also impressive
- it extends from 39 to 20,000 Hz , +4, -8 dB. Just as important, the APM-33W
speakers can easily handle the most demanding input from s digital source and
reproduce it with all its striking clarity, in short, the APM speakers
perfectly match our design criteria - they're clean, uncolored, and highly
musical.
Specifications
Drivers:
50 square
inches APM-type woofer;
1 square
inch APM-type tweeter
Frequency
Response: 39 Hz - 20 kHz +4, -8 dB
Sensitivity: 91 dB SPL
1W/1m
PowerHandling
Capacity: 80 watts nominal, 160 watts
maximum
Nominal
Impedance: 6 Ω
Crossover
Frequency: 2,2 kHz
Enclosure
Type: Bass Reflex
Dimensions
(W x H x D): 315 x 540 x 320 mm
(12-1/2" x 21-1/4" x 12-5/8")
Weight: 14,4 kg (31 lb, 10 oz)