Fostex FE-103 Memorial Backhorn by John Hagensieker If there’s one thing I’ve learned since I’ve become interested in audio equipment it’s that it usually costs entirely too much money. I’ve also learned that the "do it yourself" approach saves valuable money and provides quality comparable or usually better than retail sales. I had recently built a set of Bottlehead Paramour 2A3 SET amps and a Bottlehead Foreplay tube preamplifier. What my system needed was a pair of reasonably efficient speakers. Basically the choices were to spend big bucks or to attempt a DIY speaker project. I decided to try and make my own. Since I live in Japan, I decided to base my system around a pair of Fostex drivers that are readily available and relatively cheap over here. Since I’d never really successfully made anything out of wood before besides a splinter, I decided that my project not only had to be inexpensive, but as simple as possible with as detailed a set of plans as possible. I finally stumbled across the Fostex Recommended Back Load Horn project for the FE-103E. The drivers I chose were the FE-103M, Memorial addition drivers. I believe that these are not yet available in the U.S. The plans were very detailed and contained a drawing showing exactly how to layout the cuts on a single sheet of material. This single detail was extremely important in my final selection of a viable speaker project. After some searching I found a store in Japan that sold sheets of high density particle board. No MDF seemed to be available in my region of Japan. I had my wife, who is Japanese, ask the clerk if there was any possible way they could cut my sheets according to plan. They agreed and provided me with precision cuts on their programmable saw that I would have been unable to duplicate no matter how hard I tried. I also bought some clamps of sufficient size, a small square and a measuring tape that was graduated in millimeters. The Fostex recommended plans were drawn with all measurements in millimeters as well. One more stop at the local hardware store for some fast setting wood glue and I was ready to embark on my very own DIY speaker project. I found the construction to be very straight forward, and found the purchase of the builders square to be the most important tool. Fit and finish of the cabinet turned out to be excellent after construction. Based on recommendations from the Single Driver Forum I opted to leave the horn passages clear with no dampening material. The speaker terminals were installed 20.5 mm down from the top of the cabinet on the back. This prevented me from drilling any holes in any of the baffles and routing excessively long internal wiring. While I would have preferred to have the terminals a bit lower on the cabinet this appeared to be the most elegant solution. To date the cabinets have not been finished and may remain so as I am strangely content with the appearance of the final product. Sometimes simplicity turns out to be the most attractive option. While I can’t recite any numbers indicating frequency response or bass roll off, I can state that the speakers sound wonderful and well beyond my expectations of what I imagined they would sound like. Bass is plentiful and the Fostex drivers provide crystal clear mid range and highs. While they don’t image as well as I’d like I suspect a lot of that has to do with speaker placement and the poor acoustics of my office where my system is located. So far everyone that has had the opportunity to hear them have been impressed, and the most common comment I receive is that no one can believe the amount of sound and the quality of the sound coming from mere 4” drivers. I’m convinced that DIY speaker projects provide excellent quality for minimum expenditure of funds. Total cost of this project was approximately $75 per speaker including speaker wire, binding posts and glue. I honestly believe that comparable sound from retail speakers would easily cost more than double or triple that figure, possibly more. Photos of construction: Top