<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> </head> <body> <div class="moz-cite-prefix">On 6/22/22 10:57, David Kastrup wrote: </div> <blockquote type="cite" cite="mid:87h74cto0p.fsf@fencepost.gnu.org"> <pre class="moz-quote-pre" wrap="">"David W. Jones" <a class="moz-txt-link-rfc2396E" href="mailto:gnome@hawaii.rr.com"><gnome@hawaii.rr.com></a> writes: </pre> <blockquote type="cite"> <pre class="moz-quote-pre" wrap=""><a class="moz-txt-link-freetext" href="https://www.sciencedaily.com/releases/2022/06/220622101415.htm">https://www.sciencedaily.com/releases/2022/06/220622101415.htm</a> If sound can be seen optically, can it be generated optically? Say, to go with a hologram? </pre> </blockquote> <pre class="moz-quote-pre" wrap=""> I was of the opinion that laser-based interferometry microphoning off window panes had already been standard fare of secret services for decades. I don't think you really want to use the kind of lasers that successfully push surfaces around. Plasma speakers <a class="moz-txt-link-rfc2396E" href="https://en.wikipedia.org/wiki/Plasma_speaker"><https://en.wikipedia.org/wiki/Plasma_speaker></a> are enough of a high-energy ickiness. </pre> </blockquote> Yah, I thought that a laser able to generate sound would be a bit too strong to use around people. Plasma speakers. Fascinating. Is there a connection between the volume of the plasma and the frequency range it can produce? Such as, needing a bigger box of plasma to produce bass frequencies? I think my favorite sound-producer is still a pipe organ in a cathedral. :) <pre class="moz-signature" cols="72">-- David W. Jones <a class="moz-txt-link-abbreviated" href="mailto:gnome@hawaii.rr.com">gnome@hawaii.rr.com</a> authenticity, honesty, community <a class="moz-txt-link-freetext" href="http://dancingtreefrog.com">http://dancingtreefrog.com</a> "My password is the last 8 digits of π."</pre> </body> </html>