W 140.38 Fibonacci

Engineering concept

The membrane design is the core of the "Fibonacci" collection by RS Speakers. The diaphragm features a custom para-elliptical profile, enhanced with a folded edge structure to increase rigidity in this critical area of the cone. The patented "Fibonacci" technology involves a precise erosion of the cone's outer surface by laser marker, following a path inspired by the Fibonacci sequence, named after the Italian mathematician who numerically defined the "Golden Ratio," a harmonious form found in nature. The primary advantage of this technology is the reduction of unwanted resonance modes in the cone. The diaphragm is treated with an acrylic coating on the front and a damping layer on the back, creating a "sandwich" structure that balances rigidity and damping. Special attention has been given to the suspensions, both in terms of geometry and materials: the NBR butyl rubber surround has a dual-wave profile to ensure symmetrical cone excursion. The Conex spider is meticulously crafted with controlled moulding depth to maximize excursion while minimizing dynamic offsets. The voice coil is built on a fiberglass former, maintaining perfect mechanical stability even at high temperatures and under extreme dynamic conditions. The magnetic circuit is designed to ensure maximum symmetry of the magnetic field flux in the gap, and an aluminum demodulating ring is included to reduce the overall inductance of the coil and harmonic distortion. Every element of the woofer design concurs in the quest for the purest sound, the ultimate target for RS.

Characteristics

• Unique custom design paper pulp cone “Fibonacci”, patented technology
• Damping cone treatment
• Rubber surround with Double Asymmetric Rolls technology
• Conex spider with progressive waves
• 1,5” voice coil fiberglass former
• Ventilated magnet and voice coil to reduce power compression
• Ferrite magnet circuit with aluminum demodulating ring
• Free compression basket design: thin spokes to eliminate rear reflections of the cone