Dayton Audio ND90-PR 3-1/2" Aluminum Cone Passive Radiator Tune small enclosures with Dayton Audio's ND90-PR 3-1/2" passive radiator in speaker designs where a conventional port is not a viable option. This compact passive radiator includes all of the features you expect with larger radiators including high excursion capability, aluminum cone, rubber surround, and adjustable mass. Visually identical to Dayton Audio's popular ND series drivers, the ND90-PR can be used with any small speaker. The threaded rod and included wing nut on the back of the cone makes it easy to add mass to tune the radiator as needed for your projects. Whether you are building a multi-driver array, sound bar, or portable Bluetooth speaker, the Dayton Audio ND90-PR introduces a new range of possibilities. The ND90-PR 3-1/2" passive radiator includes: (1) Passive radiator (2) 7.3 gram disk weights (1) Wing nut Specifications: • Fs: 53.8 Hz • Vas: 0.05 cu. ft. (1.5 liters) • Qms: 6.15 • Cms: 1.09 mm/N • Mms: 8.1g • Rms: 0.44 kg/s • Sd: 31.2 sq. cm. • Xmech: 9 mm • Dimensions: Overall diameter: 4.07", Cutout diameter: 3.35", Depth: 2.39". Tip: As a general rule, the passive radiator(s) should have at least double the displacement of air (Vd) as the active woofer(s)/subwoofer(s) in the system. To calculate Vd: Sd x Xmax = Vd
