The Sundown U Series is our premier “standard suspension” woofer series. It is the most direct replacement for the world famous Z v.3 woofer line which we produced from 2011 to 2016 before launching the “new platform” Z v.4 series. Due to numerous advancements in our design process the U Series is able to deliver performance on-par with the Z v.3 series but at a much lower cost.

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.

Specifications

Black Aluminum 3” voice coil former for superior heat dissipation
High Temperature Round-Wire CCAW voice coil with high-temp black adhesive
Double stitched surround
Heavy duty cast basket
Spring loaded terminals accept up to 8 gauge
Stitched-on double-XL tinsel leads
Rear vented pole piece
Rear drilled gap-venting
Innovative high-velocity cast aluminum vented frame spacer ring
Magnet ID shorting ring
Top-Plate Cooling Channels
Cast Aluminum surround bolt-on rings
Optimized for small ported or bandpass enclosures

Specifications

T/S SPECS	U 12" D2	U 12" D4
RE (Ohms)	3.8	6.1
FS (Hz)	42.2	40.0
VAS (L)	17.9	12.3
Qes	0.30	0.38
Qms	2.67	2.93
Qts	0.27	0.34
Le (mH)	2.41	3.67
BL (NA)	31.2	33.7
Mms (Grams)	290.2	284.5
Cms (uM/N)	0.05	0.06
Sens (dB @ 1w/1m)	88.4db	85.0db

Suggested

	SD-2 10"
Sealed	0.5 ft^3
Ported	1.0 ft^3
Displacement	0.11 ft^3
Depth	4.75"
Outside Diameter	10 1/2"
Cut-Out	9 1/4"
Recommended Tuning	32hz
Recommended Port Area	16 in^2

Discontinued Speakers

X-Series v.2 6.5" Subwoofer

Refurbished SFB-2000D Amplifier

Sundown Audio U-Series v.1 12" Subwoofer

Sundown Audio U-Series v.1 10" Subwoofer