Fostex BK-20 Folded Horn Kit - Pair

Fostex BK-20 Folded Horn Kit - Pair
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Price: $719.00


Manufacturer: Fostex
Product ID : BK20-Kit
Weight: 150.00 lbs
Manufacturer: Fostex
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Fostex BK20 – 8” Full-Range High Efficiency Folded Horn Kit

Price shown is for a PAIR, and includes over a 10% discount on the drivers and parts

Limited Edition FE208-SOL Special can be used in this kit!

Madisound is pleased to bring you the BK20, a high efficiency single driver speaker kit. The Fostex FE206En 8” Full-Range driver is combined with a Fostex designed folded horn enclosure. The driver is run full range without a crossover, with a very lifelike and engaging overall presentation. These speakers can be driven with very low powered amplifiers and effortlessly produce satisfying sound levels for all room sizes.

The FE206En is the most popular 8" full range in the long running Fostex line. This driver offers high sensitivity, large cone area, immediate midrange, and excellent high frequency reproduction. Loaded in the BK20 enclosure, the FE206En provides robust low end extension. The F3 is about 45Hz and the roll off is gradual.

The cabinets are locally cut by CNC machine from high quality multi-layer 11/16” Baltic Birch and delivered flat packed. The side walls have been grooved to make positioning and assembly incredibly easy. The front baffle is doubled up per the Fostex plans, and the through hole for the driver is chamfered to promote optimal air flow. Wood glue, clamps and a little sand paper are all that is required for assembly. No soldering or wood working required. Detailed assembly instructions are also included.

Completed cabinets measure 35” tall x 12-1/2” wide x 17” deep. The unfinished/unstained wood is ready for your choice of finish. You may also choose to round over the edges if you prefer that style of appearance. High quality internal hookup wire (Supra Classic 1.6) and damping material (Acousta-Stuf) and are included with the kit purchase. The rear of the cabinet is already cut for the TD-CUP dual binding post input cut. This allows for the easy addition of a super tweeter if desired. The Fostex T90A is our recommendation.

Nominal impedance ~ 8 ohms
Sensitiviy ~ 96db
F3 ~ 45 Hz

We also offer the BK12m 4.5" and BK16 6.5" Full-Range high efficiency folded horn speaker kits.

BK-20 Kit Includes:

Tools Required for Assembly:

  • Elmer’s Wood Glue
  • Sand Paper
  • Bar Clamps (3x 24", 2x 36" - the more the better. Available at your local hardware store, or online at
Shipping Note: This kit is heavy! Depending on your location, the shopping cart may not be able to provide a shipping total. Please sumbit your order with the $0.00 shipping option selected, or email us ( with your shipping address for a quote. We will find the most cost effective way to ship to you.

Fostex FE206En 8" Full Range Driver

Closeup of Front Baffle Construction

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Product Reviews

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Reviewed by
10/25/2016 - 02:05:14 AM
Great cabinets
These cabinets are fabulous, and for mid-sized rooms (I have them set up in a 14'x17' room) they offer plenty of bass (which is the concern of many folks). I used the modified Fostex 206en drivers that Decware offers (called the DFR8), which have many of the basic mods you'll read about on the forums, including a finely machined phase plug. It's true that the highs are crisp and clear and very revealing, but I never find the sound to be harsh, which is why I shelled out the extra money for the phase plugs. The cabinets, it should be said, are NOT simple to put together. They require a lot of patience, a lot of head scratching, cursing, and dry-fitting. The key is to dry fit as much of the cabinet as you can during each step before you glue and clamp. Also, you simply cannot have enough bar clamps. I found that between 6 and 8 36" clamps did the trick. And you'll need a second person for some of the fitting, especially as you get near the end of the process (the sides). In the end, however, what you get is an absolutely amazing-sounding and -looking cabinet. The Fostex drivers sound wonderful in these, and after several hours of running music through them, they do indeed start to reach further down. I felted the rear panel (the panel opposite the magnet) of the cabinet and used the Acoustistuff poly fill in first chamber. If you've never finished birch before, you definitely need to do your research. Birch is a very, very demanding veneer to work with (it's famously difficult to stain evenly--just read any woodworking forum). I sanded these cabinets, sealed them with sanding sealer/wood conditioner (a must), and brushed on a satin clear. Birch veneer makes for a beautiful, elegant, and modern look, and in my opinion a clear finish brings out the wood's best qualities. How do they sound--awesome. I have an all-tube setup, listen to mostly vinyl, and I love what I hear through these cabinets. I listen to all types of music, from Tycho to Arvo Part to Neko Case to the Cure, and I have a sizable jazz collection. Acoustic music sounds the best, but isn't that true of just about any speaker? There are times when I yearn for a deeper bass response (when I'm listening to James Blake or Bonobo, for example), but those moments are the exception. But, when I put on a track with Paul Chambers, the sound of the acoustic bass is flat-out remarkable--rich, full, detailed, fast, and BIG. When I spin tracks that have a lot of big, artificial bass (like Aphex Twin or Daft Punk), I want more from the low end. But not enough to even think about adding a sub. There's just not one speaker for all music, and there's always a trade off. The best part about Hi Fi is enjoying the music, and I'm loving rediscovering my record collection. If you're rolling with tubes, I highly recommend this kit. You'll be pleased, for sure.