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.
| 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 |
| Specification | D2 Model | D4 Model |
|---|---|---|
| RMS Power | 1500 W | 1500 W |
| Peak Power | 3000 W | 3000 W |
| Displacement | 0.24 cu ft | 0.24 cu ft |
| Mounting Depth | 9.05" | 9.05" |
| Outside Diameter | 15.59" | 15.59" |
| Cutout Diameter | 14.01" | 14.01" |
| Motor Diameter | 9.68 | 9.68 |
| Sealed Enclosure | 2.0 cu ft | 2.0 cu ft |
| Ported Enclosure | 3.0 cu ft | 3.0 cu ft |
| Recommended Port Tuning | 35hz | 35hz |
| Recommended Port Area | 48 sq in | 48 sq in |
| Xmax | 30mm | 30mm |
| 4th Order Sealed | 1.5cu ft | 1.5cu ft |
| 4th Order Ported | 4.5cu ft | 4.5cu ft |
| 4th Order Port Area | 90sq in | 90sq in |
| 4th Order Port Length | 6" | 6" |
| Parameter | D2 Model | D4 Model |
|---|---|---|
| Re | 3.80 Ω | 6.10 Ω |
| Fs | 37.9 Hz | 34.9 Hz |
| Qms | 3.1000 | 3.4800 |
| Qes | 0.3400 | 0.3900 |
| Qts | 0.3100 | 0.3500 |
| Vas | 54 L | 63.900 L |
| Mms | 355.70 g | 353.00 g |
| Cms | 0.05 mm/N | 0.06 mm/N |
| BL | 30.700 T·m | 34.600 T·m |
| Le | 2.44 mH | 3.80 mH |
| Sd | 1141.9 cm² | 1141.9 cm² |
| Xmax | 30mm | 30mm |
| SPL (1W/1m) | 91.2 dB | 90.2 dB |