FD51-4PM – Polymaker Edition

FD51-4PM in Single Hex cabinet

FD51-4PM is another version of FD51 released for you to make at home. FD51-4PM utilises then benefits of Polymakers filaments to enable a higher sensitivity driver compared to FD51-4OS. This driver is 4.7dB higher in sensitivity, whilst improving bass response, making it capable of performing as well as 2 FD51-4OS drivers. This improved efficiency also enables designs to last longer in battery based enviroments.

FD51-4PM utilities higher tolerances and a revised magnet motor compared to FD51-4OS. It also has a higher compliance. With this in mind, FD51-4PM is more of a challenge to make and is easier to damage with over driven. FD51-4PM is built for 3W to 5W power handling.

FD51-4PM is released under the Creative Commons – Attribution – Non Commercial license. Polymaker have supplied the materials during development to make this driver possible.


FD51-4PM is also a great educational tool for anyone learning or interested in acoustics. The design has been made compatible with Thomas Sanladerer’s M3-SK experimentation kit, allowing you to change up your driver and cabinet.


What do I need to make FD51-4PM?

  • Polywood (For Cone & Former)
  • Polyflex TPU 95A (For Surround & Spider)
  • PolyMax PLA / Polysmooth / Polywood (For Chassis & Cabinet)
  • 2x (15x10mm) N35 Neodymium Magnets (Per Driver)
  • 37SWG Wire (0.17mm) or 33AWG (0.18mm) copper wire
  • M5 Washers x9 (15mm Diameter maximum)
  • Contact Adhesive Glue

FD51-4PM adds only washers as a component compared to FD51-4OS. This change is due to extracting more power from the magnet motor design, which is helped from the Polymaker filaments. Most of the advantage is from the Polywood material reducing moving mass.

Below is a zip folder of the FD51-4PM files. This driver is completely compatible with previous FD51-4OS cabinets, and will continue to support all FD51 cabinet designs.

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