The 21NLW9001 is an ultra low frequency 21 inch neodymium high performance transducer. The transducer is the evolution of the 21NLW9000 subwoofer, and has been optimized for direct radiation and bandpass subwoofer cabinet designs. For optimum results recommended amplifier should be able to deliver 3600 Watt program power without clipping. At the heart of the updated design stays the improved double silicon spider based on DSS technology, letting the 21NLW9001 being able to control the moving mass with high linearity, showing an exceptional stability of mechanical parameter values in the long term. The transducer design features include a high performance large displacement suspension system for improved cone control at very high level of SPL matching. Eighteen Sound engineers have obtained the best possible results with today's available materials in terms of clean and undistorted LF reproduction at a ultra high SPL, with the lowest possible power compression figure. The state-of-the-art 5,3" diameter ISV copper voice coil is an inside-outside split winding, four layers design, enabling the 21NLW9001 to handle up to 3600W program power. Bl force factor, as well as all other electro-dynamic parameters, are linear within the working range. The high excursion design (70mm before damage, ±14mm linear Xmax) makes the The 21NLW9001 capable of amazing SPL in direct radiation enclosures and its motor has been developed after intense FEA and fluidodynamics simulation and testing, focusing on dissipating the heat generated by the powerful 5.3" coil. Special attention was given to the optimization of air flow into the gap without introducing audible noise. A special low density material air diffractor placed into the backplate acts as a cooling system, increasing the power handling capability and lowering the power compression figure. The low distortion and sound quality are further improved by an aluminum demodulating ring (SDR technology) that flatten impedance and phase with a constant power transfer. The carbon fiber reinforced, straight ribbed cone shows a proprietary resin treatment for extra pulp strength and water repellent properties. A special coating applied to both the top and back plates makes the transducer far more resistant to the corrosive effects of salts and oxidization.
Mounting and Shipping Info
Nominal Diameter533 mm ( in)
Nominal Impedance4 Ω
Minimum Impedance4.0 Ω
Nominal Power Handling11800 W
Continuous Power Handling23600 W
Frequency Range25 - 1500 Hz
Voice Coil Diameter135 mm (5.3 in)
Surround ShapeTriple roll
Woofer Cone TreatmentWeather protected
Recommended Enclosure300.0 dm3 (10.59 ft3)
Recommended Tuning33 Hz
Resonance Frequency31 Hz
Vas272.0 dm3 (9.61 ft3)
Sd1662.0 cm2 (257.61 in2)
Overall Diameter545 mm (21.46 in)
Bolt Circle Diameter520 mm (20.47 in)
Baffle Cutout Diameter492.0 mm (19.37 in)
Depth250 mm (9.84 in)
Flange and Gasket Thickness18 mm (0.71 in)
Net Weight13.4 kg (29.54 lb)
Shipping Weight15.5 kg (34.17 lb)
Shipping Box570x570x290 mm (22.44x22.44x11.42 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.