Hi Roger I think it is fairly easy to draw ellipses. A  measuring device, 2 small nails, a piece of string and a pencil (along with a  little calculation) is all that's needed. 2*a = major axis length2*b = minor axis length For the 900mm x 1700mm ellipse; a=850mm and b=  450mmdistance from center to the "foci" (2 focus points)  is c;c = square root of (a^2 - b^2)length of string = 2*(c + square root of(b^2 +  c^2)) = 2*(c + a) ; both these equations together show that a is not only the  major axis radius but also the length of the hypotenuse from one focus to the  end of the minor axis!The string should not stretch, make it long enough  to tie a knot so the loop circumference is the length just  calculated.Locate the specified center point and draw a line  through it at the specified tilt (inclination), locate the 2 foci at the  distance c from the center (on this line), drive nails (or screws) at these 2  foci and use the string and pencil to draw the ellipse! The woodworker's motto: Measure twice, cut  once. Happy speaker construction! Jeff 
	----- Original Message ----- From:To:Jeff RobinsonSent: Sunday, February 11, 2001 11:47    AMSubject: Ellipse pattern for bass    horn Hi Mr.Robinson >>Hi Roger - Sorry if my posted design was    misleading<< Not at all !! . . .I try to drawn the ellipse pattern(For bass horn)    on the full size wood or paper..May I ask? Is any easy way to do    it? Best regards and best wishes to youRoger C...