SEAS has developed the new Graphene Nano-coating material in cooperation with the Nanobiomechanics group at the CIC nanoGUNE center in Spain, a leading research institute in Europe. This graphene coating ensures better audio performance, ensuring higher damping as well as the stiffness of the magnesium cone, as well as better corrosion protection to the drivers in the new Excel Graphene line.
As the Norwegian company details, more than a thousand engineering hours and significant investments have been put into the Excel Graphene product line. "Linearity, dynamic capability and clarity have our highest priority, for truthful reproduction of high-res audio. The W18EX003 (E0074-08) is a state-of-the-art High-Fidelity mid-woofer, intended for bass reflex designs."
The precision cast, machined, and Graphene treated magnesium cone acts as a piston through the working frequency band without showing any sign of midrange resonance. High purity Graphene, when added to the surface of the SEAS Excel magnesium cones - known for its low moving mass and its high stiffness and damping - adds further beneficial properties, protecting the cones from corroding, and also making the finished product look much better.
"High damping magnesium is the best material for woofer cones because of its damping properties and light weight, combined with the good sound speed which stems from the stiffness-to-weight ratio. For woofer cones, the damping is of highest priority, even if it compromises stiffness a bit, because the woofer cones have their early break-up modes inside the audible frequency range," SEAS explains.
The new W18EX003 is 5.7-inch diameter woofer with a 1.5" voice coil (39mm), specified for a 40Hz to 3kHz frequency range, with 280W short term power handling (160W long term power handling), with a sensitivity of 87db, at 8 Ohm. For the W18EX003, a titanium voice coil former with a moderately long copper voice coil winding offers a very stiff connection to the cone and provides excellent force transfer, achieving large linear excursion, while the non-conductive former also doesn’t add any damping to the excursion, which allows for a very precise and transient sound reproduction, without electromagnetic damping.
An FEA optimized magnet system with precisely fitted copper parts for improved linearity and symmetry also provides higher power handling and low transient distortion. A heavy copper ring below the T-shaped pole piece reduces nonlinear and modulation distortion and an additional copper cap in the air gap of the magnet system reduces distortion and voice coil inductance, resulting in a sound without colorization.
The exact geometry of the pole piece is optimized for completely linear inductance, independent on input power, and with only +/-10% variation over the +/-10 mm excursion range of the woofer. A unique radial reinforced rubber surround reduces radial resonances and prevents surround break up at large excursions.
Finally, the extremely stiff and stable injection moulded metal basket keeps the critical components in perfect alignment. Large windows in the basket both above and below the spider reduce sound reflection, air flow noise and cavity resonance to a minimum.
"The combination of low mechanical and electromagnetic damping ensure high quality reproduction and brings out even the finest micro details in music. The high-performance magnet system and titanium voice coil and its connection to the cone has very high power-handling, suitable for modern amplifiers (e.g. Class-D). Therefore, the driver has exceptional high dynamic capability, which the light and stiff and well damped magnesium cone transfers into clean and undistorted sound, suitable for truthful High-Res audio reproduction," SEAS details.
When the original Excel line was launched in 1993, more than 25 years ago, it started a new era for SEAS and these drivers immediately became recognized for their excellent qualities, even by today’s standard. With the new design in the Excel Graphene line, every aspect of the speaker from input to output has been scrutinized and optimized. For distribution (DIY) the Excel Graphene speakers are packaged in pairs.