The Sundown SLD series can be considered a “re-boot” of the SD-2 line from 2011. The SD-2 was essentially a “shallow SA v1” by design – meaning it shared the cone, surround, and spider with the SA but with a shorter motor with a shorter coil. The SD series went another route starting with the 3rd generation (SD-3) – tilting more towards SQ and sealed enclosures (this remains true for the SD-4 series as well). Due to popular demand we created the SLD series to add a heavily abuse tolerant “shallow” that likes ported boxes back into the line-up!
Much like the current SD-4 series we utilized solid pole-piece so the SLD can also be mounted directly against the rear enclosure wall to reduce net depth requirements. Compared to the old SD-2 we have introduced numerous important upgrades: pole-piece channels for reduced air noise & increased cooling, top-plate “slits” for better cooling and less distortion, and a magnet ID shorting ring. In terms of long-term reliability we have also bolted down the spider, bolted the motor together, bolted on the aluminum pole cap, and added “mini-XL” lead wires thus ensuring many years of flawless service.
The bottom line is if you need a relatively shallow woofer that will take a beating then the SLD is, hands-down, the woofer for you from our line. If you are looking for more SQ then look toward the SD-4 series.