I tried much how the tweeter of RCA to sound that I bought last time. At the result , I made for it to use a hard and plane board. I tried some materials of a board.
Although I tried by the U.S. pine plywood, Shina plywood, etc., In the case of the U.S. pine, I hear a spread of sound seems to be slightly soft. In the case of the Shina plywood, I hear somehow soft the touch which return of sound. Although I hear also naked, there is no spread of sound too. When I talked to my friend various kind of the board of a speaker, He said harder tree was better, he brought the board. He said that he does not understand what tree it is. Although I did not understand, either, it is an anyhow very hard tree. When I was going to make the 10mm hole with the electric drill, smoke came out from the motor. Although I cut with JIGUSO after all, The strange wooden smell and a very fine thing like powder came out. It took about 10 minutes to make only 8cm whole.
When it completed, it differed just a little bit from the time of U.S. pine plywood & Shina plywood, The good high sound came out. There was worth which suffered troubles. I satisfied very much. I will write next time, the tweeter in the photograph next to it.