Paraflex 21 C2A Golden

Elements Audio along side Matthew J Morgan Have designed and released our first ever free plan Speaker cabinet design

The 21 C2a Golden Formula Paraflex subwoofer achieves improved performance by the use of a Throat Chamber in conjunction with an increased rate of expansion in the Low-Tuned Horn resonator section... This increased gain/sensitivity & output within the cabinet's working range typically comes at the cost of sacrificing some surplus upper extension. The 21 C2A has a playable range 30Hz to 90Hz with extreme spl.

The 21 C2a Took over 1 year to design and prototype, with the finished result being one of the best performing Paraflex models available as a free plan. There are detailed plans in both Metric and Imperial to follow, and a large number of detailed photos outlining the build process and build order.


From Sheet Material to finished Design!


We hope this video can inspire you on how to build one of these stunning cabinets, and the best way to assemble one, once you have cut all parts. We have also listed some of the tools your need.

  • Pencil.
  • Tape measure, steel rule.
  • Track saw, Jig saw.
  • Hand router.
  • Drill, Drivers, and basic hand tools.
  • Set Square
  • Yellow Glue
  • Screws
  • T nuts, Bolts,
  • 4mm 2 core speaker cable

21 C2a Golden Paraflex


Amazing depth and clarity sound, with a great usable bandwidth, The 21 C2a is extremely clean and clear sounding with amazing depth to its tones, even at high spl. The Cabinet is an easy 2 man lift, with center of gravity kept low to help making it easy to move when needed. Careful thought and design when into the bracing to reduce weight yet keep the box strong, with out adding any unwanted resonance's from the bracing. The driver is very tightly controlled and even at full power, the driver stays under constant control.

Many videos and info on this cabinet can be found on the HOQW group on facebook, with many people adding there build pictures and videos of this design in action.

21 C2A Golden will test even the most experienced of builders, when it comes to assembly, but if you follow the build pictures your be very happy with the finish cabinet. Feel free to ask questions and help over on the facebook group page, Myself and Matthew are happy to help.

Good luck with your build, Should you wish to build any for your own use. Any speaker builders who build for profit should first contact us for a licence if you are charging other people to build this cabinet for them, this includes cnc cutting flat packs. This free design is intended for the home diy builder to enjoy and build.

We recommend you use 18mm Baltic birch ply, with 13 laminates to 18mm. Other materials will work, but wont be optimal.


Ben Wells

Ben is the founder and owner of Elements Audio, He has a passion for all things Audio related, Ben is a master joiner by trade, and overseas all builds, and heads up the design team.

Post by: Ben Wells