Whoever mentioned the thing about special steel being used in the original EMTs is right. Not to dissuade anybody from building their own plate but I've built two in my time and could never get the cold rolled metal to sound right. Then I got my real EMT. Even before I ever plugged it in I took a quarter to it and brush it passed the steel and voila, magic. None of the sheets of metal I used in my homebrews ever shimmered like that. I never tried stainless steel in my home built plates, but Jim Cunninham the plate guru once told me that he used stainless in all of his ecoplates because it was way more consistent sounding.