SONY APM-66ES

Commentary

This is an APM3-way speaker system with enhanced perfection of each item such as a tweeter using amorphous diamond, a multi-point drive woofer, and an acoustic launched enclosure.

424 cm in the lower range²Uses APM type woofer.
The aluminum honeycomb vibration plate is driven by multiple armatures directly connected to the voice coil, and the concept of multi-point drive which effectively cancels the divided vibration is developed, and the divided vibration up to higher mode is canceled by a total of 8 armatures.
As a result, we have acquired approximately five times the pistic motion bandwidth of the equivalent cone type woofer, and achieved a flat wide playback bandwidth of up to 4 kHz.
In order to take advantage of this drive system, it is equipped with a magnetic circuit with low distortion design such as a T-shaped pole piece with excellent symmetry of magnetic flux and a perforated yoke that reduces back pressure of the vibration plate.
In addition, the high-efficiency oxygen-free copper edge-wise voice coil and die-cast frame using an amide bobbin with high heat resistance and high rigidity are used to achieve more faithful reproduction of digital sources.

48 cm of double-sided drive system in the middle area²APM type mid-range is adopted.
The vibration plate uses three layers of reinforced aluminum skin material based on aluminum. The surface of the reinforced aluminum material with fine cavities inside is treated for vibration control. This increases the synthesis and reduces the internal loss. Both sides of the sweet spot of the material around the vibration plate are driven to improve the rise and stretch of the sound.
The magnetic circuit features a T-shaped pole piece, a perforated yoke, and a copper cap to ensure a low-strain design. In addition, it uses the largest class strontium ferrite magnet, oxygen-free copper coated aluminum edgewise, and voice coil.
In addition, the lowest resonance frequency is designed to be low by adopting a back chamber.

9 cm with an amorphous diamond vibrating plate for the high-frequency range²APM type tweeter has been adopted.
Amorphous diamond is a carbon material with physical characteristics very close to diamond, and the sound velocity reaches 18,300m/sec. We have succeeded in vapor deposition of this new material on aluminum skin material, and excellent transient characteristics are obtained by the synergistic effect of high sound velocity, high synthesis, and aluminum honeycomb structure.
In addition, the voice coil is made of lightweight and highly efficient copper-coated aluminum edgewise wire. The magnetic circuit is equipped with one of the largest class strontium ferrite magnets, and magnetic fluid with high heat dissipation and damping effects is injected into the voice coil cap.

The network section uses carefully selected parts with low distortion, low loss, and audibly examined.
For the Woofer coil for which a large current flows, a thick wire with a wire diameter of 1.5 mm is used to prevent deterioration of sound quality due to resistance. In addition, each coil uses an air core structure suitable for each coil and a silicon steel core to suppress distortion and noise turbidity.
In addition, two coils for the woofer, the tweeter, and the mid-range are arranged on two boards perpendicular to each other is perpendicular to each other, and the boards are distributed in positions where interference is least.
In addition, a large electrolytic capacitor in a highly vibration-proof plastic case and a polyester film capacitor can be selectively used to obtain a clear reproduction sound without any peculiarity.
Oxygen-free copper is used for internal wiring materials such as coil wires and capacitor leads.

A. R. E. (Acoustic Rolled-Up Enclosure) with R at four corners is adopted in order to avoid diffraction phenomenon of sound wave which is reflected at the corner of the enclosure by sound wave emitted from the speaker.
In addition, the APM-66ES has a slant on the upper front surface to reduce diffraction phenomena in the high frequency range.
The enclosure is made of high-density particle board made from chips of North American conifer trees. In addition to sufficient plate thickness and reinforcement, narrow grooves are provided inside the back plate to minimize box rumbling and noise and tune it to a natural sound.
Finished with wood-grain black finish.

Equipped with level control, both mid-range and tweeter can be adjusted from 0 dB to 50 dB.

A special speaker stand is available and sold separately.
The stand can be bolted securely to the bottom of the enclosure and is at an optimum height for the listener seated.
A sound-absorbing sheet is attached to the top of the stand bottom plate to prevent sound reflection.

Model Rating

Method	3-Way, 3-Speaker, Bass reflex system, Bookshelf Type
Unit	For low band : 424 cm2Plane type For Medium Range : 48 cm2Plane type For high frequency : 9 cm2Plane type
Playback frequency band	28 Hz to 45000 Hz
Output sound pressure level	90dB/W/m
Impedance	6 Ω
Maximum instantaneous input level	200W
Rated input level	100W
Crossover frequency	600 Hz, 4.5 kHz
External dimensions	Width 380x Height 660x Depth 365 mm
Weight	27kg
Attachment	Speaker cord
Sold Separately	Speaker Stand WS-660 (2 pcs 1 set, ¥ 20,000)