Herb -- This is an interesting topic because I did some work on this for the Altair32 Emulator. I just dug the code out and it was just about 10 years ago. I was trying to add the ability to directly read WAV files (22050Hz, 8-bit) from within the emulator and Bob Grieb helped me with the Fast Fourier Transform code needed to make it work and tought me a bit about DSP and filter design. The add-on basically became a WAV-to-digital converter based on the Altair ACR recording format. I don't think it ever made it into the main code tree because of the inability to locate WAV images at the time. Rich -- Rich Cini http://www.classiccmp.org/cini http://www.classiccmp.org/altair32 On 5/10/18, 5:45 PM, "vcf-midatlantic on behalf of Herb Johnson via vcf-midatlantic" <vcf-midatlantic-bounces@lists.vintagecomputerfederation.org on behalf of vcf-midatlantic@lists.vintagecomputerfederation.org> wrote: http://www.retrotechnology.com my home page starts with Web links to my VCF-East talk, and to a Web page stuff I'll be selling there as a vendor. http://www.retrotechnology.com/restore/cass_data.html There are adults alive today, who have *no idea* what an "audio cassette" is! Shocked me. Learn how the Ancients communicated in tones! Lost technology, recovered by experts, even as we speak. Voices from the past! http://www.retrotechnology.com/vcfe_may18.html Less exciting fare. I'm adding more by the day. Lights that blink, boards covered with chips, clicky keyboards. Some of you know me - ask me about something I have you don't see. Root around my domain to see more. No IMSAIs No Altairs pls, light stuff OK? Surprisingly, I don't get axed much, about old Macs. Herb "The Beep" Johnson -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net