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PostPosted: 17 Nov 2009, 05:05 
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Joined: 06 Jun 2008, 18:23
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About to to assemble the back loaded horn for the Fostex FE206En driver. The boxes cost me $AU800 and drivers $AU360 so not a cheap speaker.

Anyone else done it?

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PostPosted: 17 Nov 2009, 13:29 
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Mark, I think you are really going to like the FE206En in a horn. Here are my Dallas Back (Rear) Loaded Horn Speakers with Fostex FE206E. I sent you photos of the few mods I have tried with the driver thus far. I want to try a few more.

Be patient with them. You will need to adjust damping in the compression chamber and at the mouth of the horn. The Fostex FE206E Recommended Speaker Enclosure Plans suggests "sands" (sand bags I assume), but I used styrofoam cut to size to adjust the chamber.

Also, take a look at this page for more ideas about damping in the compression chamber.
http://www.humblehomemadehifi.com/Solo206.html

Keep us posted! :headphones:

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PostPosted: 17 Nov 2009, 22:05 
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I have built and listened to the double bass chamber and now the back loaded horns. Though far more complex, costly and heavy the back loaded horns are much better. But I could easily live with either. My all up cost for the back loaded ones is about $AU1200. I had the boxes made by a friend.

Please yourself with the BSC but (as Gio pointed out) a Zobel of 4.7uf and 8.2ohms is a must. It just takes some of the midrange grain out. Also in my large and slightly lively listening room there initially was an excess of upper bass with no lower bass. A roll of Dacron rolled and stuffed into the bottom back open chamber fix this problem in one go, The upper bass was converted to lower bass at about twice the volume. I think there may have been some reflection and doubling happening back there. You cannot see the roll it tucks right down. Sound stage is stunning and stereo image good on tracks that have it.

From my 6W RMS pp SE UL JJ KT88 Blue Glass amp I can make my ears hurt with no compression or clipping. Very, very loud if you want it. Be warned these are very efficient speakers.

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PostPosted: 17 Nov 2009, 23:01 
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Fantastic Mark. They really look great! I would not spend too much time tweaking them until the driver is well broken in as they will change some. Feeding them 50Hz while you are at work will speed this up, but watch the level. I think you will find that a zobel will not be necessary with all amps.

How do you plan to finish them?
Cheers

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PostPosted: 17 Nov 2009, 23:02 
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Gio wrote:
How do you plan to finish them?

Maybe just a clear or honey or walnut coloured lacquer? No sure yet.

Something I didn't mention is these boxes are held together with stainless steel screws and dowels and glue and up to 8 massive braces were used on them at one time. They are extremely well made. Probably more solid than normal.

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