Aurex SS-F90

Commentary

A three way speaker system that uses a flat diaphragm made of C. R. polymer.

The C. R. Polymer (Cell Rigid Polymer) developed by Rolex is a special rigid foam. It has a completely sandwiched structure with a soft high foam inside and a hard skin layer made of ebonite. This material has the same internal loss as paper, high rigidity, and light weight.
In order to realize wide-band reproduction by taking advantage of this characteristic, the diaphragm is in the shape of a nebular (nebula), and has a convex lens shape close to a plane with a thick central part and a thin peripheral part, so that the strength in the central part where stress is large can be sufficiently high.
Furthermore, in order to solve the problem that parts (nodes) that do not move at all appear at certain frequencies when the flat diaphragm is driven at the center, we have adopted a bobbin that drives the center part of the diaphragm, a triangular truss structure that is fixed at the outermost periphery of the diaphragm with a subcone, and a dual drive system that simultaneously drives the inner and outer peripheries of the diaphragm, thereby suppressing resonance to a level that is virtually unproblematic.

Modal analysis technology has been newly introduced to analyze the sound quality of flat speakers in the vibration mode of the diaphragm and the vibration mode of enclosure.

In the lower range, the C. R. Polymer flat diaphragm, first introduced in the SS-F50, was studied and analyzed using modal analysis technology. Further improvements have been made to enhance the completion of the 32 cm flat woofer.
The diaphragm is a truss structure dual drive system that drives the center part and the outer part simultaneously. In addition, a center reinforcing ring is provided to increase the strength of the voice coil bobbin in order to reduce transmission loss.
In addition, an aluminum die-cast frame is adopted to eliminate unwanted resonance, and it is fixed to a 25 mm thick baffle plate with a large aluminum die-cast fixer.
A newly developed 160 mm φ large strontium magnet is used for the magnetic circuit, and the shape is a T-pole to reduce asymmetric distortion caused by unbalanced magnetic flux in the magnetic gap.
The voice coil is a 75 mm φ large diameter type and uses an edgewise wire with excellent space factor per unit area.

The mid-range is equipped with a 12 cm flat skoker that uses a C. R. polymer flat diaphragm, which has been improved by modal analysis as well as the woofer. A reinforcing rib is provided on the back of the diaphragm to minimize split vibration, thereby achieving low distortion. In addition, a newly designed aluminum die-cast frame is used for the frame.
A large strontium type 133 mm φ magnet is used for the magnetic circuit. In addition, aluminum edgewise wire with high space factor is used for the voice coil, and T-type pole used for the woofer is also used to reduce asymmetric magnetostriction.

A 3 cm flat type tweeter using C. R polymer oxygen-free copper is installed in the high range. The high range characteristics are improved by adopting the sandwich structure which takes advantage of the moderate internal loss of C. R polymer and the high rigidity skin material.
Newly developed aluminum die-cast is used for the frame to suppress the squeal of the frame and prevent the sound from becoming muddy.
The magnetic circuit is a special type in which a magnetic fluid is inserted between the magnet and the voice coil to increase the heat radiation effect of the voice coil and improve input resistance. In addition, the polyimide laminated film with excellent heat resistance and high Young's modulus is used to increase input resistance and realize high-speed response. In addition, aluminum edgewise wire is used for the voice coil with aluminum short ring to reduce magnetic strain.

In the network section, we carefully select magnetic materials suitable for each frequency band, and use air-core coils, ferrite coils, laminated cores, etc. in the right place. We also arrange network elements so that sound quality is not adversely affected by induction between coils.
Oxygen-free copper with excellent sound quality is used for the wiring of the tweeter and squaker.

The attenuator switch is a 4-step switching type for both the tweeter and squaker.
Unlike the winding type, it is an attenuation type using metal oxide film resistance, which is said to have good sound quality. We have also examined the materials of switches to achieve low loss and low distortion factor.

The enclosure takes advantage of the flat diaphragm by adopting a tapered baffle plate in which the sound emitted from the diaphragm is not disturbed by interference or diffraction effects.
The tapered baffle is a 25 mm thick conifer particle board with a modal analysis to determine the position and shape of the stiffener. The cabinet is made of the same conifer particle board as the baffle surface to achieve sound quality with excellent vibration damping characteristics due to moderate internal loss.
Symmetrical design is adopted for the unit layout.

Model Rating

Method	3-Way, 3-Speaker, Bass reflex system, Bookshelf Type
Speaker used	Low Band : 32 cm Flat Type For Middle Area : 12 cm Flat Type For High Frequency : 3 cm Flat Type
Frequency characteristic	30 Hz to 30 kHz (SPL-10dB)
Crossover frequency	800 Hz, 8 kHz
Max Input	150W
Rated input	75W
Output sound pressure level	90dB/W/m
Impedance	8 Ω
Level adjustment	Each 4-step step for middle and high sound (+ 2, 0, -2, -4dB)
Internal volume	Approximately 70L
External dimensions	Width 430x Height 720x Depth 344.5 mm
Weight	33kg