Fostex BC10 Full range system

　
Began April 23 , 2000

　It was a plan for a long time to build a full range system of BC10.
At last it has begun. BC10 is an unit made of alminum casted frame,
alnico magnet, 7N Cu voice coil, 10% bio-cellose cone. It's a gorgeous
one,but hard to get new one by now.





　　I wanted to make a good enclosure, so I found "Reo" designed by Junichiro
Irie, it's concise. It's made of pine , with buffle 15 cm width, which is almost the
same as European 2 way.

　So I made up my mind to reform low cost Uniwave speaker. This is the same
as European 2 way's enclosure, and have a hole for an unit and it's suitable for
full range system.

　　Firstly I removed felt and units. Secondly I shaved up corners. It was easier
because I 've crafted a violin for half a year.

　Then I removed paint by sand paper. Skin of wood appeared gradually, but It was
difficult to remove all the paint, for it was painted without sealer. Paint has invaded
in the wood. So I'm planning to paint that dark color.

　　The hole was rather small for BC10. I enlarged the hole with a trimmer. Holes for
bisses were just fitted.

　　The frame of BC10 is tapered, so it looks fine without trench on the baffle. But actually
it looked poor , so I made a trench.

　　I set length of blade 3 mm and shaved the baffle. It is difficult to shave out precisely
by free hands, so I used the Hotate* shaver I invented for the last 1 mm.



　　* means scallop

　　This time I had to make the Hotate, so I tried a method to make a hole
with trimmer formerly I invented. I set diameter 104mm, because I had a plan
to use FE108S in the next project.



　Method




　As shema above I made a center hole 4mm diameter. Fixed this hole with a biss,
and made it turn.

The test was successful.

　　Cut down edge is usually decorated with hinoki wood plate. But it should be
done before construction. But this time it was not done. I thought about this
difficulty but I found an easy method by using trimmer.

　　Trimming the edge by 1.8mm depth , and attached hinoki plate. After that
finished it by plane.

　Now let's look back the enclosures designed by Junichiro Irie on monthly STEREO.

　　These are the boxes reasonable and simple. If cut down edge is hidden, they look
good.

　　The weak point of these boxes is to make round edges is difficult. In that case thick
front baffle is employed.





　　In the rigidity of baffle Irie's method is supposed to be superior to this.
　

　 This time first step is painting. (Painting is a fun!) Maple color lacqer has been
tried. It's a bright color and it has a woody appearance. But this time it was'nt
employed.
　Dark brown cashew racqer was employed instead. I found this made good quality.
It's an elegant color and looks slightly purple.





　　When I drilled holes of screw to the back baffle, its surface was broken by
　drill. We should be carefull to the exit of drill. Then I shaved it by trimmer,
and placed thin hinoki(Japanese cypress) plate.

　Now finished all through this. Cashew racqer was painted 3 times. Back baffle
was painted black. Brushed horizontally and it nearly became mirror surface.





　　Terminals were Tritec's product as it looks gorgeous. Micron wool was
sheeted at lower space.





　I listened to Mutter's violin on this speaker drived by YAMAHA's amplifier.
Maker's amplifier or tube amplier will be selected for this unit is precious.
The sound was cooler than FE103.

(finished May 5, 2000)

Frequency response
　　　




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