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The Amp Hour

High End Audio with Remco Stoutjesdijk

Oct 4, 2021 · 1 hr 7 min · Episode 560 · 64.8 MB
0:00-1:07:51

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Welcome Remco Stoutjesdijk of ItsOnlyAudio.com!

  • Remco calls himself a "recovering audiophile"
  • Why didn't we stop trying to improve audio setups in the 70s?
  • Remco started with vacuum tubes but moved into silicon at Wolfson Micro. He got his first job by writing a letter asking if they needed anyone and his hobby projects helped to place him into special projects group.
  • "If you work in hardware you play with simulators. If you work in software, you play with hardware". This is why he moved into applications.
  • For a little while, he worked at Rohm Semi on LEDs
  • Back into audio with ASK industries, who make hardware that is used in stereo setups for cars that are branded with Bang & Olafsson and Burmester.
  • Differences between car and home
    • Extreme conditions, like Audi running a 36 hour "sun test"
    • Fixed acoustic environment
  • One thing they did was to develop a tuning tool for the end brand (ie. B&O) to tweak with their experts
  • Big things they were working on was outside noise cancellation and engine noise cancellation
  • However, not all sound is bad. "Putting the car in 'sport mode' pumps more sound into the cabin"
  • They're really trying to find the acoustic transfer function (of say, the engine) to reverse any impact it has on the listener's ears.
  • Unwanted noise is first put through a filter. Then they have to apply filter before sound arrives.
  • An example transform is a Levinson-Durbin recursion
  • Active Noise Control (ANC) isn't really "cancellation"
  • It's important to think about the stability, since it's a control system
  • Often they're looking for the lambda coefficient
  • After going out on his own, Remco and his family moved to Poland. Polish is a difficult language to learn. It's on a remote branch of the "tree of languages" (which show the inheritance of different languages and the other languages they're based upon)
  • Poland has a growing tech scene
  • Past guests Jan Rychter and Michael Gielda from Ant Micro (and most of the team) are based in Poland, though in different areas. "7Sensing" is another dev shop out there.
  • Remco is now consulting via ItsOnlyAudio.com and is a member of the Consulting forum (apply here if interested in joining).
  • When not working on client projects, he is building up IP library and bringing demos to audio shows
  • ADI Sharc DSP
  • Shannon Parks episode
  • Tools of the trade for doing audio on chips
    • CMSIS DSP library
    • Components of that library
      • Biquad filter
      • DMA buffers
      • Ring buffers
  • Loudness war website
  • Push to custom silicon are necessary for super phase sensitive items
  • PTP - Precision Time Protocol based on UDP
  • Chris wondered if Disney World does something like this to synchronize speakers throughout the park? BoingBoing article
  • Dunte protocol
  • AVB
  • Audio ecosystem is fairly small, though there are some startups now
  • Modern audio need to tie into Alexa / Google / Apple for streaming
  • OCA - open control alliance (warning: autoplay audio??)
  • Signal processing / fidelity is as good as it can get, wow we need to improve playback environment
  • Improving noise comfort for loud urban environment
  • Chris and Remco have both used binaural beats to try and drown out sound in the past
  • Find Remco online