Fostex FE208Sigma in Folded Horn Enclosure by Douglas Fudge Introduction: I’m writing this article as my first entry into public speaking. Please be assured I am truly a novice hi-fi nut, woodworker, and wordsmith. I make no claims of greatness; I will claim only that I enjoyed building the enclosures and enjoy listening to the speakers. I will assume everyone has or has access to the tools necessary to build speaker enclosures and has some hi-fi experience. Thanks. I’ve been into the stereo/audio/hi-fi thing for over 25 years now, but had never really been so into it as to experiment electronically or to build my own speaker enclosures. I had read a couple of magazines and was contemplating doing some weird things with my Klipsch Heresys, crossovers, and bi-amping. Well, I purchased a Conrad Johnson MV52 to compliment my Yamaha M80 and this bi-amping project…but, Before that all got started I was surfing the net and became engrossed by full range drivers, and the whole Lowther phenomena. However, after looking at prices of the Lowther's and their perceived exclusiveness - and the disgusting prices of some enclosure kits offered - I was totally put off by the whole Lowther "experience", even without experiencing it at all. I’m sure they are a great product, just not one I am prepared to venture into for the price. I saw the Fostex’ and immediately became interested due to the price and the theory that I could have a full range driver, build my own enclosure (that was a "Lowther" type design) and be happy doing it. I surfed the net looking for plans and assistance. I had become really stuck on the Fidelio’s when I ran across Craig Schmidt’s article here for the FE208s in the Fidelio cabinet. Wow, what a break, I had struck gold! I e-mailed Craig with tons of questions, and he was kind enough to respond with answers, advise, and plenty of wisdom. Thanks Craig. His first guidance was to steer me away from the Fidelio’s (it had been done already with the Fostex’), and visit a German site which features horn speakers specific to the Fe208s, the cabinet plans are here. I downloaded the plans and went to work. In a few days I had the cabinets drawn to size and materials laid out. The plans are in millimeters, so you may need a mm scale – a 400mm works great. There is also another site which features a plan for cabinets made for the Fostex’, it is Ulrich Haumann's Plasma Tweeter site and the Jericho Horn is here. I purchased the Fostex drivers via the Internet. It was painless and fast. From click to UPS delivery was three days. Madisound now carries Fostex drivers. Not knowing how they would sound, I didn’t want to spend a bunch of money on real wood for my first project so, I bought two 4x8 sheets of ¾" MDF for around $15.00 each. I had the lumberyard cut each sheet lengthwise so they would be easier to handle. Have the pieces cut an inch or so wider than you need so you can make the final finish cuts at home. First, I ripped boards for the four sides (without changing the adjustment on the table-saw) to ensure they would all be the same width – which they are. Second, I set up the saw to rip the boards for the many pieces which formed the horns, fronts, backs, tops, and bottoms of the enclosures. Again, without changing the table saw adjustment between cuts. Third, after all the large pieces were ripped the correct widths, I measured and cross-cut the four sides to length, then I cross-cut the interior pieces two at a time (or in the case of the tops and bottoms – four at a time) to ensure they would all be the same. Also, there were a few angle cuts to be made, but I cut the boards straight first, then when all straight cuts were made, I adjusted the angle of the saw blade and made the angle cuts. The fewer times you have to adjust your saw, the better. Next, I set two side pieces (remember, there are four sides exactly the same dimension) next to each other and began to transfer measurements to the boards from the plans I downloaded. Don’t confuse yourself with mirror images and symmetry, lay both sides out exactly the same. Be absolutely certain of the measurements as you are making your layout lines. Check the measurements again. Again (I said that twice). Once you glue a piece in position, it’s a very ugly proposition to change it! I find it sometimes helps if I simply stand the pieces up on edge as if I was gluing them just to see the object come alive – In other words, dry fit everything at least twice. The piece that holds the speaker itself is essentially a doubled-up piece. You can use the four edge pieces the plans show, or simply double-up a whole piece and cut your 185mm hole in them both. Do this before you do any other assembly. Once that sub-assembly is complete, then you can begin assembling the cabinets. You may also want to decide at this point where to place your terminal posts. Pre drill or cut as necessary now. I started gluing up the cabinet pieces beginning with the speaker frame and the top of the cabinet being glued to the side first. Since there are not really clamps to hold these pieces in place, lay the cabinet side on the floor or a sturdy table, glue both pieces and fit together. Set another board on top of the glued pieces and weigh it down with books or something similarly heavy – I used cans of paint, lots of them! Do both cabinets at the same time. Be absolutely certain each board you glue is perpendicular to the side panel – check it twice. Errors here will ruin your project. Remember that you cannot have any gaps between boards in your enclosures. I did not use any screw or nails in my construction, so it limited me to how many pieces I could glue together at a time. Usually I glued one piece per cabinet side, waited 8-12 hours and glued another. You’d be surprised how fast they went together. When gluing the pieces to the sides, start with the speaker frame and working your way through the horn in succession. Then, glue up the back, then the bottom, and finally the 45º corner pieces. The cabinets should be complete except for the remaining side panels! Only after you have mounted your terminal posts and wiring should you contemplate gluing the remaining side panels in place. To glue the remaining side panel, place the panel – dry – against the enclosure. Trace the outline of the horn foldings onto the remaining panel (slide your hand up the horn and through the speaker hole). Lay the single side panel flat on the floor or table and apply glue to the panel inside the tracing lines. Apply glue to all edges of the cabinet which meet the remaining side panel. Set the cabinet on the side panel, square it, and weigh it down heavily. Allow to dry. The reason not to lay the cabinet down and to put the side panel on from the top is that excess glue will run down along the inside of the cabinet walls and horn foldings. MDF is very forgiving, and lends itself to really a quite good finish of paint or varnish. I used wood filler to hide some marks left by my saw blade, and then sanded it smooth. After sanding, I used an oil-based primer and then an oil- based paint to complete the project. An additional departure from the plans was that I changed the way the bottom of the cabinet was constructed. I trimmed the sides and back flush with the bottom and then added another bottom piece that is 2 inches narrower and 2 inches shorter than the enclosure bottom so that the speaker appears to sit slightly up from the floor. Purely esthetics, and I don’t believe it changes sound quality at all. All together these speakers cost less than $40.00 in material, far less than the thousand dollars some kit providers ask for just about the same thing (sure I could’ve spent $125.00 on nice veneer ply, but I didn’t) And - same as Craig’s - they are heavy, they weigh in at 68lbs each with speakers! Oh, by the way, they sound great! Top