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.
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Features (U-10 / 12 / 15 / 18)
- 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
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| T/S SPECS |
U 15" D2 |
U 15" D4 |
| RE (Ohms) |
3.8 |
6.1 |
| FS (Hz) |
37.9 |
34.9 |
| VAS (L) |
54.0 |
63.9 |
| Qes |
0.34 |
0.39 |
| Qms |
3.10 |
3.48 |
| Qts |
0.31 |
0.35 |
| Le (mH) |
2.44 |
3.80 |
| BL (NA) |
30.7 |
34.6 |
| Mms (Grams) |
355.7 |
353.0 |
| Cms (uM/N) |
0.05 |
0.06 |
| Sens (dB @ 1w/1m) |
91.2db |
90.2db |
Enclosure Specifications
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| Sealed Enclosure |
2.0 cu ft |
| Ported Enclosure |
3.0 cu ft |
| Recommended Tuning |
35Hz |
| Recommended Port Area |
48 sq in |
| Displacement |
0.24 cu ft |
| Depth |
9.05″ |
| Outside Diameter |
15.59″ |
| Cut-Out |
14.01″ |
