<<Neither demonstrates anything related to actual pianos and how they work.>> Maybe not, but the difference in tone between the relaxed (non-"crowned") board and the arched ("crowned") board while the fork was vibrating was definitely noticeable, even striking. But since this isn't related to real pianos, what's the purpose of crown again? On the same subject (I think), what is the correct answer to clients who ask what makes pianos go out of tune? We used to tell them that, aside from the natural tension to go flat because of the tendency for wire under tension to stretch, the soundboard rises and falls with changing humidity, but since it has been proved or calculated that the "numbers just aren't there" to support that theory, what is a short, satisfactory answer to the question, or is there one? Yes, I know this has been discussed before and somebody will probably respond, "Archives! Archives! Archives!" but I don't recall a concise satisfactory answer. --David Nereson, RPT <div class="gmail_quote"> On Sat, May 12, 2012 at 4:50 PM, Ron Nossaman <<a href="mailto:rnossaman@cox.net" target="_blank">rnossaman@cox.net</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> On 5/12/2012 5:04 PM, David Nereson wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> I believe Yamaha made those also, as a sales aid. </blockquote> Yes, I think so. They made a crown "arch" demonstrator, I know. <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> They'd be simple to make </blockquote> Yes, but why? Neither demonstrates anything related to actual pianos and how they work. They're both pure snake oil. Poor snake... Ron N </blockquote></div>