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#474 – An Interview with Nash Reilly
Welcome, Nash Reilly of Sonos!
- Chris and Nash met at OSHWA 2018
- Nash is from Montana and went to engineering school at Montana State University.
- His first job out of school was at Micron over in Boise, doing SO DIMM testing for large scale customers.
- He actually tested for things like Cosmic Ray strikes, discussed many times on this show.
- Interned at Sonos when it was 100 people
- Watching how the vendors change their tune as you get volume up
- His role at Sonos started in sustaining engineering
- Making sure supply chain is stable
- Spent 4-5 weeks per year in China, even had to leave vacation to fly to China.
- “Type 2 fun”
- Smoke jumpers for Intel
- Hank Zumbahlen episode
- Staying well grounded
- Lee Hill’s Silent Solutions
- I2S clocks hurt emissions, are often a problem during testing.
- Blog post about emissions
- Solutions for I2S clocks
- Changing the output impedance of your driver
- Put a small external RC filter
- Howard Johnson on the podcast
- First 20 pages of the Black Magic book
- Most DACs/ADCs aren’t as finicky as they used to be
- I2S is just SPI in one direction
- Sigma Delta DACs
- Oversampling and modulating in the reverse direction
- THD is like a noise measure, but also has distortion
- Audio Precision test equipment
- Analog Dialogue
- Charty Party
- 30 ms for it to be instantaneous to a human
- Humans are more sensitive to phase delta
- Latency is constant for digital signals
- 3rd edition of AoE
- ADI AN-283
- The Way Things Work
- How do you maintain quality over low quality speakers that are out there?
- Clicks and pops
- “A class D amplifier is just a motor driver with an LC on the output”
- Layout starts to impact things
- Chapter 8 of AoE for low noise design
- Sonos Port
- 20 people in his group, including digital, analog, layout
- Current project has 10 people in total or so
- 1600 total people working at Sonos
- Sonos Amp
- Had to do a custom class D amplifier
- Needed to design in real time control
- Sonos use Linux computers internally for the high level control
- Microcontrollers for controlling other elements of the design faster
- Nash is in charge of making sure the digital section is put together well and writing test plans
- An example schedule: December start (talking with vendors), April schematic, June testing
- For the Sonos Move, Nash worked on an earlier incarnation.
- Nash’s main site/blog
- Find him on reddit
- Nash is @cushychicken