The 8NMB420 neodymium transducer has been developed in response to a specific market requirement for a 8" midbass driver that combines excellent linearity with good efficiency and high power handling capabilities. 8NMB420 is primarily intended for use as a midbass driver in compact 2-way or multiway reflex enclosures comprising line arrays. The parameters had been chosen to offer significant low frequency output in vented enclosure with size starting from 20 lit. with a tuning frequency around 60Hz. The low pass filter might be positioned as high as 2000-2500Hz. Multiple 8NMB420 units might be used: the compact size reflects in the capability to have precise attack time. This characteristic makes it the ideal choice for stage monitoring and bass guitar amplification. The extremely powerful external neodymium magnet assembly assures high flux concentration, low power compression and excellent heat exchange. The levels of force factor and power handling are, as a consequence, at the upper professional level with best power to weight ratio. The exclusive dedicated double roll surround design offers enhanced linear travel and control, in order to reproduce precisely low frequency. The curvilinear paper cone is formed using a unique wood pulp composition designed to achieve the best possible rigidity and stiffness. The 50mm inside outside aluminum voice coil employs Interleaved Sandwich Voice coil (ISV) technology. It is composed by a high strength fiberglass former used to carry windings on both the outer and inner surfaces to achieve a mass balanced coil. This results in an extremely linear motor assembly which, in conjunction with the highly advanced design of the magnetic structure, provides a high force factor or BL. The voice coil is cooled incorporating airways between the chassis back plate and the magnet faceplate so that heated air is channeled away from the voice coil and gap and dissipated by the chassis basket. Thanks to the increasing use during outdoor audio events, the ability to perform in humid environments is a key feature of the 8NMB420. This is achieved trough a proprietary humidity repellent cone treatment without a moving speaker mass increase.
Mounting and Shipping Info
Nominal Diameter200 mm ( in)
Nominal Impedance4 Ω
Minimum Impedance3.2 Ω
Nominal Power Handling1280 W
Continuous Power Handling2400 W
Frequency Range60 - 5500 Hz
Voice Coil Diameter51 mm (2.0 in)
Woofer Cone TreatmentWeather protected
Recommended Enclosure20.0 dm3 (0.71 ft3)
Recommended Tuning67 Hz
Resonance Frequency59 Hz
Vas31.0 dm3 (1.09 ft3)
Sd227.0 cm2 (35.19 in2)
Overall Diameter210 mm (8.27 in)
Bolt Circle Diameter195 mm (7.68 in)
Baffle Cutout Diameter186.0 mm (7.32 in)
Depth99 mm (3.9 in)
Flange and Gasket Thickness14 mm (0.55 in)
Net Weight1.7 kg (3.75 lb)
Shipping Weight2.0 kg (4.41 lb)
Shipping Box235 x 235 x 150 mm (9,25 x 9,25 x 5,91 in) mm (9.25x9.25x5.91x0.35x0.20 in)
2 hours test made with continuous pink noise signal within the range Fs-10Fs. Power calculated on rated minimum impedance. Loudspeaker in free air.
Power on Continuous Program is defined as 3 dB greater than the Nominal rating.
Applied RMS Voltage is set to 2.83 V for 8 ohms Nominal Impedance.