Digital Designs DD Audio Z421 21" Subwoofer




In early 2005 the first-ever iteration of the Z motor was launched. It forever changed the way people thought of a high-performance subwoofer and pushed the limits of car audio to new extremes. Over the years, many versions of Zs have been produced and this spirit of experimentation has driven us to constantly improve and innovate.

This sub rightfully takes its place as one of the most dominant competition subs of all time even though it wasn’t actually designed for competition. The motivation behind the Z was simply to build the best sounding high power handling driver of all time; to that note DD Audio considers the Z mission accomplished.



There have been a couple of different iterations of the Z4 over the years, and due to the limited number of pieces that have been produced it has gained almost mythical status in the subwoofer world. In its current form, the Z4 is an 18 lens grade 52 neodymium open motor design. By increasing the surface area of the voice coil, the size of the magnetic gap, and its heat dissipating abilities, the Z4 is able to be driven just as hard as the Z3, but with increased long-term high power handling.

The USA steel and aluminum motor parts are machined and finished in our hometown of OKC, and all the moving parts are USA made from the finest materials and manufacturing methods available. These parts are then assembled and QC’ed in our OKC facility. The motors are adorned with CNC engraved Z artwork, and every motor is engraved with its unique production number. All steel motor parts feature a Zinc and Black Chromate plating that gives each Z motor a unique look with the surface color ranging from matte to different iridescent hues. This plating provides excellent corrosion and heat resistance while minimizing coating thickness and maximizing energy transfer between motor parts. To further compliment the Z’s striking motor cosmetics the aluminum quick-change top plate, and shorting rings both feature red anodized accents.

You’ll notice the standard TS parameters are missing for the Z subs. This omission is on purpose because each Z is custom built to order allowing for Zillions of possible parameter sets making one static set of specs very prone to inaccuracy. The reason we build Zs custom to order is it gives a system designer the utmost freedom to design for their specific application.

The Z Series subs also feature our Evolution Subwoofer Package (ESP). ESP equipped drivers sport larger diameter suspensions and deeper frames than standard subs and exclusive surround and cone designs. ESP subs are truly built to maximize performance in their designated size class.

The Z Series comes standard with an oversized dry finish black composite dust cap, red logo, and treated pulp cone, but it can be optioned out with custom suspension configurations, alternative composite dust caps, composite cones, powder-coated frames, and a multitude of logo options to give your sub a personalized look and/or added performance for a specific application.



DD Audio will continue down the path of global transducer domination via the sledgehammer of the subwoofer world….THE Z



  • Driver Size 21"
  • Watts RMS 1500 – 6000
  • Peak Power 12000
  • VCD 4
  • Impedance D1 / D2
  • Piston Dia – in 18 1/4
  • Frame OD – in 21 5/16
  • Frame OD w/Gasket – in
  • Mounting Diameter – in 19 1/4
  • Mounting Depth – in 13 1/8
  • Motor Diameter – in 10
  • Motor Depth – in 5 5/8

                  Related Products