[HN Gopher] Yamaha DX7 chip reverse-engineering, part 4: how alg... ___________________________________________________________________ Yamaha DX7 chip reverse-engineering, part 4: how algorithms are implemented Author : Tomte Score : 69 points Date : 2021-12-10 20:29 UTC (2 hours ago) (HTM) web link (www.righto.com) (TXT) w3m dump (www.righto.com) | kens wrote: | Author here if anyone has questions... | samuelous wrote: | Just want to say that I am incredibly thankful for this series, | its amazing to see how one of my favorite synths works not just | in theory (FM/PM) but also on the chip level. Thanks! | null4bl3 wrote: | Thank you for a good series of articles and some great insight | into the inner working of FM synthesis in general. | | I have never owned one of the original Yamaha's, but i have | been using the awesome Dexed VSTi plug in, that is modeled | after the DX7 for several years now. | | And I am planning on purchasing a Korg Opsix for its FM | capabilities. | | But for someone that has only been on the learning-by- | experimenting end of FM synthesis, your articles are a great | insight into the theory behind it all. | dezgeg wrote: | How much time does reverse engineering this kind of chip take? | kens wrote: | It takes a while. I got the chip on Nov 1 and have been | working on it since then. (Although it's not the only thing | I've been doing.) The process is a combination of taking die | photos, tracing out circuitry, understanding the circuits, | doing background research, and figuring out how to explain | the chip in blog posts. | backspace_ wrote: | I feel like there was a missed opportunity with the title, why | the departure from using Roman numerals and call this article | part IV? | kens wrote: | A missed opportunity in what way? Is "IV" better than "4"? | S_A_P wrote: | I've never been a huge fan of FM synthesis as I'm mostly | reminded of bad electric piano sounds that came out back in the | 80s. Having owned a tx-7 I knew it was capable of more than | that but then there was the whole issue of programming it that | kinda sucks. | | That said seeing the tech and how things were implemented has | me loading up the Arturia DX7-V and tinkering around with it. | | Have any other synths or effects on your list to look at? | joezydeco wrote: | Once you got past the bad piano sounds, it was in way too | many arcade and home video systems to keep track of: | | https://en.wikipedia.org/wiki/Yamaha_YM2151 | | One of my favorite pieces is Brian Schmidt's music for | _Swords of Fury_ , a Williams pinball machine from 1988. | | https://www.youtube.com/watch?v=RMIp5nG-C3o | robbrown451 wrote: | Here is a very good WebAudio implementation of DX7, so you can | hear what it actually sounds like: | https://www.webaudiomodules.org/wamsynths/dx7 | faeyanpiraat wrote: | Doesnt work on iphone | ctdonath wrote: | I have a DX7 I might part with... | dboreham wrote: | Intriguing to imagine the first time the designers heard the | sound their creation could make (presumably there was a TTL or | bit-slice prototype before the VLSI implementation). They're | sitting around the lab, someone plinking away on the keyboard. | One of them says "you know, you could use that sound on a pop | record and I bet it would be popular for at least a decade". | kens wrote: | The story behind FM synthesis is pretty interesting. A Stanford | music professor, John Chowning, came up with the idea in the | 1960s and patented it. Stanford didn't think this was what a | music professor should be doing and fired him. Meanwhile, | Yamaha licensed the patent from Stanford, paying millions of | dollars and making it Stanford's most lucrative patent at the | time. Stanford changed their mind about Chowning and hired him | back, making him a full professor and then department chair. | | For more information, see: https://priceonomics.com/the-father- | of-the-digital-synthesiz... | npunt wrote: | Great read. Images aren't loading on that link but wayback | machine to the rescue: https://web.archive.org/web/2015032322 | 2119/https://priceonom... | TheOtherHobbes wrote: | The early FM pieces weren't very pop. | https://www.youtube.com/watch?v=988jPjs1gao | | You may think it sounds crude, but pieces like these took | hours of expensive mainframe (PDP-10) time. There wasn't a | lot of opportunity for careful sculpting of fine details. | | You could easily synthesize something like this in real time | now. But not many people do, which I think is a shame. | | If you can read French, there's more background here: | http://brahms.ircam.fr/analyses/Stria/ | ctdonath wrote: | _hours of expensive mainframe (PDP-10) time_ | | Equivalent today to milliseconds of processing in an Apple | Lightning cable. | redler wrote: | That clip sounds like something straight out of the | soundtrack from Close Encounters of the Third Kind. | duskwuff wrote: | > If you can read French, there's more background here: | http://brahms.ircam.fr/analyses/Stria/ | | If you can't read French, use Google Translate. It handles | this article extremely well. | TonyTrapp wrote: | > Stanford changed their mind about Chowning and hired him | back | | Somehow I feel that if this happened today, no company or | university would have the spine to do this, and it would | rather turn out as an expensive legal battle if he insisted | on getting his part of the patent pake. | motohagiography wrote: | This article series is mind blowing to me. The engineering is | fascinating. It's like they made another logical analog | abstraction layer over the digital electronics. Yamaha doesn't | get mentioned much here, but between how they can bring the | experience of their instruments, motorcycles, and sound equipment | to people everywhere, there is an understated beauty in what that | company does. They only seem to make things that are wickedly fun | and life's great pleasures. Also, this: | https://en.wikipedia.org/wiki/Yamaha_CX5M ___________________________________________________________________ (page generated 2021-12-10 23:00 UTC)