FD51-4OS – Open Source Edition

Pair of FD51-4OS Drivers assembled

FD51-4OS is the open source version of FD51, and takes what has been learnt in FD61’s development and condenses it into a design that is as simple as possible in terms of printability and component count. This is not an industry competing driver, but an easy to make proof of potential driver. Great for little projects like bluetooth speakers, bookshelf speakers, soundbars and more.

FD51-4OS is released under the Creative Commons – Attribution – Non Commercial license.


FD51-4OS 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 FD51-4OS?

Alternatively, if you are in the UK you can purchase the magnets, wire and washers through a kit I have available on eBay.


Alternative materials can be used to make FD51-4OS but results may vary.

This low quantity of components was critical in the design of FD51-4OS to make it accessible to as many people as possible. Other designs of FD51 have a larger component count, but as many components as possible can be transferred to keep costs down.

2 FD51-4OS running in the Dual Bluetooth Cabinet at 1M distance

Thiele & Small Parameters can be found by downloading the FD51-4OS datasheet below:

Files for FD51-4OS

Below is a zip folder of all the STL files to create your own FD51-4OS drivers. This includes the initial cabinets and the M3-SK lid to make it compatible with the M3-SK project:

If you like the project, and want to help support it to create better versions, consider becoming a Patreon. Your support can help push FD51 to become a better driver, along with potential to expand the options. From March onwards, Patreon supporters will gain at least 1 new STL file each month, along with behind the scenes look at what is in development!


Thanks for your interest


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