October 04, 2021

High End Audio with Remco Stoutjesdijk

1 hour 7 minutes

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

His website

His YouTube

...more

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By The Amp Hour (Chris Gammell and David L Jones)

4.9

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