[HN Gopher] Fixing a 30 year-old Roland synthesizer Bug ___________________________________________________________________ Fixing a 30 year-old Roland synthesizer Bug Author : montag Score : 60 points Date : 2022-09-12 21:11 UTC (1 hours ago) (HTM) web link (www.vogons.org) (TXT) w3m dump (www.vogons.org) | ajxs wrote: | Awesome work! I love the care and attention that people put into | understanding these devices. | | I'm currently in the middle of a vintage synthesiser hacking | project as well. Last year I made a fully annotated disassembly | of the Yamaha DX7 firmware, and did some other technical analysis | of the synth. Since then, I've been waiting for a chance to put | this knowledge to good use. I found a DX9 on a local trading | site, and I'm in the process of hacking its firmware to remove | the 4-operator restriction that made it such an unpopular synth. | NexRebular wrote: | I wonder if DX100 firmware could be hacked like that as well, | it being another of the 4-op beasts too | tomcam wrote: | > Last year I made a fully annotated disassembly of the Yamaha | DX7 firmware | | You beast! | pinewurst wrote: | The Kawai K5 I used to have was also 8096 based. | Gordonjcp wrote: | Intel 8097 in the Roland W30, and I think also the S50. | digitailor wrote: | The S550 is the unit I was fixing mentioned in another | comment, that one was a 8095 | digitailor wrote: | Didn't know that: hard to believe they managed to pull off | additive synthesis on an 8096. That's impressive | | I had a later Kawai K5000 which added short PCM samples for | attack transients. That thing was crazy, foolishly gave it away | more than a decade ago | pinewurst wrote: | I received a final software update from Kawai and had to open | it to install the EPROMs, which is how I saw it. It was a | very cool synth - very high quality feeling. | digitailor wrote: | This is cool, so TL;DR: The 3rd gen run of a Roland early digital | synth product had an unresolved timing issue causing pitch | playback problems. Recently, investigation revealed they hadn't | accounted for an Intel MCU part sub. The spec indicated the sub | part was running too fast. They downclocked it via crystal swap | which destroyed the unit's MIDI timing. So they located the | control ROM instructions to modify to fix the resulting MIDI sync | issue and burned a new one: 0x1A8D: 1D5Fh -> | 1388h 0x215C: 17h -> 0Fh 0x216D: 1D5Fh -> 1388h | | That's it. Surgical. | | I spent some time inside an early Roland sampler of this era | during the pandemic. It's really well engineered stuff that | sounds great. | tomcam wrote: | Ah, relief. Big Roland fan but don't have this particular piece | of gear hello trouble following TFA | Gordonjcp wrote: | I guess it makes sense that it would be a common divider ratio | (5000) but $1388 leapt out at me from disassembling the Ensoniq | Mirage firmware. | digitailor wrote: | That's a cool project. Mirage patches got edited in hex on a | two digit panel screen, right? | | Spent time with an Ensoniq ASR-10 rack that I managed to fry | with AES/EBU noise on the analog ins. Overhauling the PS did | not solve :/ | keepquestioning wrote: | This reminds me of the binary patching done in The Martian | film. ___________________________________________________________________ (page generated 2022-09-12 23:00 UTC)