<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div><blockquote type="cite" class=""><div class="">On Nov 26, 2022, at 9:34 AM, Ben Stuyts <<a href="mailto:ben@stuyts.nl" class="">ben@stuyts.nl</a>> wrote:</div><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On 26 Nov 2022, at 10:01, Donald Tillman <<a href="mailto:don@till.com" class="">don@till.com</a>> wrote:</div><div class=""><div class=""><br class="">I repeat: the big deal about the DX-7 was that they found a way to completely avoid real-time multiplies.<br class=""><br class="">And that includes the envelopes.<br class=""></div></div></blockquote><div class=""><br class=""></div></div><div class="">For those interested: Ken Shirriff had a a bunch of blog posts reverse-engineering the DX7 chip:</div><div class=""><a href="https://www.righto.com/search/label/dx7" class="">https://www.righto.com/search/label/dx7</a></div></div></div></blockquote></div><br class=""><div class="">Yep.</div><div class=""><br class=""></div><div class="">Here's the original Chowning article:</div><div class="">The Synthesis of Complex Audio Spectra by Means of Frequency Modulation</div><div class=""><a href="https://ccrma.stanford.edu/courses/220a/static/jcFM73.pdf" class="">https://ccrma.stanford.edu/courses/220a/static/jcFM73.pdf</a></div><div class=""><br class=""></div><div class="">Here's the original Chowning patent (which is basically his article):</div><div class="">US4018121A: Method of synthesizing a musical sound</div><div class=""><a href="https://patents.google.com/patent/US4018121A" class="">https://patents.google.com/patent/US4018121A</a></div><div class=""><br class=""></div><div class="">And here's the Yamaha DX-7 patent:</div><div class="">US4554857A: Electronic musical instrument capable of varying a tone synthesis operation algorithm</div><div class=""><div class=""><a href="https://patents.google.com/patent/US4554857A" class="">https://patents.google.com/patent/US4554857A</a></div><div class=""><br class=""></div><div class=""> -- Don</div><div class="">--<br class="">Donald Tillman, Palo Alto, California<br class=""><a href="https://www.till.com" class="">https://www.till.com</a></div></div></body></html>