5 ms·

I was the hardware lead who designed that black board you're modding. Nice work. Warm fuzzies.

by cushychicken 4y ago

harry8 4y ago
Don't just drop that and run! Tell us about the whys of the design decisions. Please?
- cushychicken 4y ago
  Many of our decisions were based on what we had driver compatibility for. Software ALWAYS took a lot longer to get right at Sonos than hardware, largely because of the huge number of internal and external compatibilities we were required to maintain. We had a working amp + DAC signal chain with the TPA series, so we reused that. We also had working wifi drivers with the MT7613. Much of my job was convincing the RF people that they didn't need to break out all the RF chains, which would have tipped the product into unprofitable territory. A lot of the design decisions were based on hardware cost and speed of development. We reused a lot of subcircuits we'd previously validated on other designs.
- lmas 4y ago
  I concur! Please share some wisdom.
AnthonBerg 4y ago
Cool! The TPA3116 is a nice sounding chip don’t you think?
- cushychicken 4y ago
  Not really - specs and sound wise, it's not any different from any other integrated class D analog input amp. Pretty run of the mill THD and SNR specs. It also has one hell of a startup transient. It was not a fun exercise to get that passing startup click/pop requirements. I said some words about TI in anger while bench testing.
  - AnthonBerg 4y ago
    Interesting! Thank you! Any chips you’re particular to?, or are otherwise interesting?
    - cushychicken 4y ago
      Analog Devices is making some neat digital amp chips that have an I2S digital feedback path from the chip to the digital source (processor or similar). The idea is that you can use this to digitally correct for imperfections in the transducer. Never used them in depth, but the demo they showed us on an EVK was neat. You can trivially pick up 6dB improvements in SNR, or more with tuning and characterization. My beef is really more centered on the fact that, if you're already at -100db of SNR, what's the point?

I was the hardware lead who designed that black board you're modding. Nice work. Warm fuzzies.

harry8 4y ago

Don't just drop that and run! Tell us about the whys of the design decisions. Please?

cushychicken 4y ago
Many of our decisions were based on what we had driver compatibility for. Software ALWAYS took a lot longer to get right at Sonos than hardware, largely because of the huge number of internal and external compatibilities we were required to maintain. We had a working amp + DAC signal chain with the TPA series, so we reused that. We also had working wifi drivers with the MT7613. Much of my job was convincing the RF people that they didn't need to break out all the RF chains, which would have tipped the product into unprofitable territory. A lot of the design decisions were based on hardware cost and speed of development. We reused a lot of subcircuits we'd previously validated on other designs.
lmas 4y ago
I concur! Please share some wisdom.

AnthonBerg 4y ago

Cool! The TPA3116 is a nice sounding chip don’t you think?

cushychicken 4y ago
Not really - specs and sound wise, it's not any different from any other integrated class D analog input amp. Pretty run of the mill THD and SNR specs. It also has one hell of a startup transient. It was not a fun exercise to get that passing startup click/pop requirements. I said some words about TI in anger while bench testing.
- AnthonBerg 4y ago
  Interesting! Thank you! Any chips you’re particular to?, or are otherwise interesting?
  - cushychicken 4y ago
    Analog Devices is making some neat digital amp chips that have an I2S digital feedback path from the chip to the digital source (processor or similar). The idea is that you can use this to digitally correct for imperfections in the transducer. Never used them in depth, but the demo they showed us on an EVK was neat. You can trivially pick up 6dB improvements in SNR, or more with tuning and characterization. My beef is really more centered on the fact that, if you're already at -100db of SNR, what's the point?