Here I posted a link which leads to an interview with michael pinnella. I found it very interesting especially where he speaks about the origin of the band's name. erm from what I understood then Symphony x simply means the unknown/ mysterious symphony isnt it?
http://www.prog4you.com/Band_Interviews-09-04/Michael_Pinnella.htm
http://www.prog4you.com/Band_Interviews-09-04/Michael_Pinnella.htm