SUNDOWN AUDIO | U SERIES V1 8″ | 750W RMS | D4

Sundown Audio U8 D4 Subwoofer:
The Sundown Audio, U series 8-inch Dual 4 Ohm Subwoofer Down4Sounds Top Pick for 8’s. The Sundown U8 is a conserve rating at 600 watts of power; these subwoofers can take the heat; they are also very musical and built like a tank. The Sundown U8 is fully capable of hitting both DEEP and Punchy Bass, The U 8 sub is one investment you thank yourself for buying at Down4Sound!
We start with a double-stacked / 8.66 wide Y35 grade ferrite magnet system coupled to a one-piece, bumped T-Yoke and a 0.6 thick top-plate. Just as with the Z v.3 before it and our other high-end subwoofers we also add a very thick (5mm thickness) aluminum shorting ring inside the magnets to reduce static inductance and level out inductance over stroke. The U series motor also features a 0.6 long pole-extension to keep the coil under control at high levels of excursion.
The voice coil is a 2.36 long / 3 diameter 4-layer aluminum winding / aluminum former unit which is the same coil we use in our X v.2 series and, thus, the U series has the same 1500-watt RMS ratings. The coil temperature is kept in check by a heavily smoothed / high-velocity pole-vent and a series of ten direct air-gap vents in the back plate. The U series also features newly tooled cast aluminum vent rings in between the frame and top plate to effectively exchange air at a high velocity over the voice coil beneath the spider landing.
The U series features an all-new cast aluminum frame series to the Sundown line which allows for taller cones than the older frames used on the Z v.3 series. The taller cones provide enhanced coil stability and increased mechanical excursion capability. We also tooled matching cast-aluminum surround clamps for the U series to ensure durability in the most demanding situations. The surrounds and cone bodies have been fully custom tooled especially for the U series and are stronger / support more excursion than the Z v.3 series cones and surrounds. The new cone bodies also feature an indentation for the same wide-flange, ultra-strong dust caps as our new platform subwoofers.
If you are looking for a woofer that sounds similar to the SA series but handles significantly more power the U series is exactly what you need. It has been designed to live up to the reputation earned by our Z v.3 series both in terms of every-day music enjoyment and SPL competition
Sundown U-8 D4 T/S Parameters

Re: 6.1228 Ohms
Fs: 52.7160 Hz
Zmax: 40.0810 Ohms
Qes: 0.6072
Qms: 3.3675
Qts: 0.5144
Le: 5.4104 mH (at 1 kHz)
Diam: 165.1000 mm (6.5 in)
Sd: 21408.3884 mm^2 (33.1831 in^2)
Vas: 2.9629 L
BL: 25.8651 N/A
Mms: 200.2935 g
Cms: 45.5082 uM/N
Kms: 21974.0859 N/M
Rms: 19.7008 R mechanical
Efficiency: 0.0672 %
Sensitivity: 80.2899 dB @1w/1m
Sensitivity: 81.4513 dB @2.82vrms/1m
Krm: 2.912E-03 Ohms
Erm: 1.001E+00
Kxm: 63.818E-03 Henries
Exm: 719.614E-03

Sundown Audio U8 D4 Cutout & Mounting Depth:

Top Mount Depth: 6.80″
Mounting Depth: 6.25″
Recommended Ported Box: 0.75-1.0″
Woofer Displacement: cu. ft. 0.011
Outside Diameter: 8.65″
Cutout Diameter: 7.375″
Recommended Tuning Frequency: 35Hz