Reverse-engineering the Yamaha DX7 synthesizer's sound chip from die photos

• hn-search

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Here are all the other articles and their previous HN discussions:

https://hn.algolia.com/?q=righto.com+yamaha+dx7

• yamaha_dx7_rom_disassembly

  4 59 7.1 Assembly

  Yamaha DX7 Firmware ROM annotated disassembly.

I wrote the article mentioned by Ken: https://ajxs.me/blog/Yamaha_DX7_Technical_Analysis.html

I've unwittingly become a bit of a Yamaha FM Synth historian!

Here are some other contributions to reverse-engineering the DX7:

A fully documented disassembly of the DX7 ROM: https://github.com/ajxs/yamaha_dx7_rom_disassembly

A new firmware ROM that makes the DX9 function like a DX7:

• InfluxDB

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  Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.

  

• music-synthesizer-for-android

  3 395 0.0 Jupyter Notebook

  Discontinued Automatically exported from code.google.com/p/music-synthesizer-for-android

  

This is for Cortex A8, which was the chip in the Nexus One. I wrote the original version of sound synthesis directly in ARM assembler[1]. It was very highly optimized, I remember using a cycle counting app that flagged any dependency chain that would cause the processor to stall, and ultimately utilization was in the 90%+ range. Back in those days, processors were simple enough you could do this kind of optimization by hand. By the time of Cortex A15 (Nexus 10 etc), instruction issue was out-of-order and much harder to reason about.

The best current info I could find for the latency advice is [2]. Quoting, "Moving data from NEON to ARM registers is Cortex-A8 is expensive..."

[1]: https://github.com/google/music-synthesizer-for-android/blob...

[2]: https://community.arm.com/support-forums/f/armds-forum/757/n...

• awesome-linuxaudio

  9 1,275 7.1 Shell

  [mirror] A list of software and resources for professional audio/video/live events production on Linux.

> Is there a highly-regarded software (or hardware + software) emulator for the DX7?

Dexed is probably what you're looking for, although there are others here: https://github.com/nodiscc/awesome-linuxaudio#synthesizers--...

Suggest a related project