AuraSound's NS18-992-4A 18" subwoofer is widely accepted as one of the best subwoofer drivers ever made. With an underhung voice coil, neodymium radial magnet, aluminum cone, and almost 2" of peak-to-peak excursion this driver is in a class of its own
Output, fidelity, and extension… Usually you have to sacrifice one in order to improve the other two. The 4 ohm 18" NS18-992-4A from AuraSound is one of the few drivers that can do it all.
AuraSound has designed the NS18-992-4A from the motor up. They started by combining a massive version of the patented Neo-Radial Technology (NRT) motor with an underhung 4" diameter high temperature voice coil to give this driver a particularly long stroke. Then, they mated the coil to an extremely rigid aluminum cone for minimum distortion. For suspension, this driver uses an injection molded rubber surround and dual opposed spiders to keep the cone and voice coil linear up to 3" of peak-to-peak mechanical excursion. To hold it all together AuraSound has developed a cast aluminum frame, which is remarkably solid while allowing maximum airflow for the back side of the cone and ample ventilation to keep the voice coil cool.
For moving excessive amounts of air while maintaining a hi-fidelity sound it will be hard, maybe impossible, to beat the AuraSound NS18-992-4A 18".
Nominal Diameter18"Power Handling (RMS)800 Watts
Power Handling (max)1600 WattsImpedance4 ohms
Frequency Response20 to 1,500 Hz HzSensitivity89 dB 1W/1m
Voice Coil Diameter3.9"
Resonant Frequency (Fs)20 HzDC Resistance (Re)3.1 ohms
Mechanical Q (Qms)7.7Electromagnetic Q (Qes)0.5
Total Q (Qts)0.47Compliance Equivalent Volume (Vas)11.37 ft.³
Mechanical Compliance of Suspension (Cms)0.17 mm/NBL Product (BL)17.65 Tm
Diaphragm Mass Inc. Airload (Mms)400gMaximum Linear Excursion (Xmax)25 mm
Surface Area of Cone (Sd)1164 cm²
Materials of Construction
Cone MaterialAluminumSurround MaterialRubber
Voice Coil Wire MaterialAluminumVoice Coil FormerFiberglass
Basket / Frame MaterialCast AluminumMagnet MaterialNeodymium
Overall Outside Diameter18.75"Baffle Cutout Diameter16.8"
Depth12.25"Bolt Circle Diameter17.5"
# Mounting Holes8
Optimum Cabinet Size (determined using BassBox 6 Pro High Fidelity suggestion)
Sealed Volume4.3 ft.³Sealed F335 Hz
Vented Volume8 ft.³Vented F323 Hz