Sundown SA "Classic" Historic Post

We brought the SA-12 to market about 5-years ago; what I didn't mention is that I started on its development in 2008 shortly after testing with the original "Monster" woofer motor (which looks like a huge SA-12 motor). The same venting techniques I developed in the "Monster" went straight into the SA-12 design -- the SA-12 was the first one we brought to market, followed by 10s, then finally 15s. The name itself shows the intention... SA simply stands for "Sundown Audio" -- this driver was to be the centerpiece and mainstay of our line, which is exactly what it has become.

The original SA-12 prototype from early 2008 had a slightly shorter magnet stack and a slightly shorter coil with no frame spacer. This prototype was a really good driver and would have done well on the market -- but I simply wasn't fully satisfied. So I moved onto a 10mm taller magnet stack and a 5mm longer voice coil (D4 was the only coil offered at first) -- and also added the first version of the frame spacer to give more mechanical clearance; which was solid at the time and the basket itself was drilled with four vent holes. We also tested several different spider varieties before settling on the one we would use; this spider is still used today on the SA-10/12/15 and SD-2 10/12 woofers. This prototype tested great and we made the first run of SA-12s with just a few 100 pieces.

After seeing how these did on the market in 2009 I made a few changes right away to the 2nd production run -- I developed our first triple joint ring (which is featured on almost every woofer we make today) to make them even more rugged, added additional vent holes for 12 total in the frame (similar to the SD-2 10/12), and also added the large magnet ID shorting ring. This configuration lasted for several production runs; but all the while I was testing several other small tweaks.

The third major iteration changed the shape of the flare on the back plate, added the tooled vented spacer ring, and changed to a larger and differently shaped aluminum pole cap. This was the last major design change -- since then we have made minor tweaks to the surround and the motor changed to chrome but the design has largely stood the test of time.

Back to the venting system originally developed for the "Monster" woofer... this system consists of the aluminum pole cap, the pole vent itself, the gap vents themselves, the pole flare on the back plate, and the basket perimeter venting. The specific way these parts interact took quite a bit of planning based on several concepts of aerodynamics to direct the air-flow in the manner I desired. I was able to further optimize it with the addition of the vented spacer ring to replace drilled frame holes and changes made to the pole cap and rear flare... but the overall system developed here has made it's way into many of our other drivers in a few different tweaked formats -- the Z v.3, Z v.4, X, NS v.2, NS v.3, and "Team" driver all features variations of this system. This allows our drivers to provide industry leading thermal performance; often times offering similar thermal performance to drivers with physically larger voice coils.

From the first production run the SA series has proven it's incredible ruggedness and has found it's way into countless SPL builds over the years. But lets not lose sight of the fact that the SA is a fantastic daily woofer with several distortion decreasing features. The motor features DUAL Faraday rings for reduced inductive distortion; most drivers in this class don't even have a single Faraday ring. Moving on the motor was FEA optimized for a full 19mm one-way linear travel by 70% BL method and the suspension was also Klippel verified to support 20mm one-way by 50% CMS method (both industry standard). It also features a very flexible parameter set allowing it's use in sealed, bandpass, and ported enclosures.

Over the past 5-years I have kept testing other prototype versions of the SA series woofers; none of which have been able to prove a superior price to performance ratio over the current design in all aspects most important to me. But... the quest continues -- anyone that knows me personally and/or has visited the shop has no doubt seen the mountains of prototypes I've tested to try to top this design. So rest assured... when an SA-10/12/15 v.2 finally sees the light of day that it will be awesome. Until then I hope everyone continues to enjoy and appreciate the SA series and all the hard work that went into it over the years.