FOSTEX SLE20W

Commentary

Edgeless 20 cm cone type woofer unit.

The edge is eliminated by the SLE (Super Long Lenear Excursion) employs an acoustic low-pass filter and a push-pull type damper.

The part corresponding to the edge of the conventional speaker is a ring-shaped slit with a facing width of 1 mm and a depth of 28 mm. This slit forms an acoustic low-pass filter and has sufficient acoustic attenuation characteristics so that the sound from the back of the speaker does not leak through the slit in the audible band and the sound pressure does not decrease.
Moreover, by eliminating the edge, problems such as amplitude distortion and treble caused by the edge, and frequency characteristic valley caused by reflection of the edge, which were caused by the conventional speaker at the time of amplitude, are solved.

The vibrating part is supported by dampers symmetrically attached at two points of the voice coil.
As a result, the asymmetry of the damper is canceled, the linearity is widened and the hysteresis phenomenon is reduced, and more accurate vibration is realized.
In addition, the materials of the damper are also examined, and consideration is given so that the slit width does not change depending on the creep phenomenon even if it is used for a long time.

SM (Synthetic Material) cone is used for the diaphragm, and division vibration is suppressed by having high rigidity and internal loss.

The A-ring (Absorb Ring) and double dust cap structure improve the characteristics of the mid - and high-frequency range.

The voice coil is treated with super-to withstand temperatures up to 230 ° C. The core paper is made of high-stiffness, flame-retardant epoxy mica resin.
This voice coil is designed to withstand large input both in amplitude and electrical terms.

There were 2 types of variations, 8 Ω and 16 Ω.

Model Rating

Method	Cone type woofer unit
Aperture	20cm
Impedance	8 Ω, 16 Ω
Frequency characteristic	Fo ~ 5 kHz
fo	27 Hz ± 5 Hz
Output sound pressure level	90dB/W/m
Input	100W(Music)
Magnetic flux density	9,500Gauss
Recommended crossover frequency	3 kHz or less
Effective vibration radius (a)	8.55cm
Equivalent mass of the vibration system (mo)	28g
Equivalent Q (Qo) of the vibration system	0.35
Magnet weight	630(ALNICO)
Weight	3.6kg