5 ms·

> The problem seems to be that sound cards (or chips) in modern PCs are too clever for their own good. They are designed to optimise microphone input for Skype

> The problem seems to be that sound cards (or chips) in modern PCs are too clever for their own good. They are designed to optimise microphone input for Skype and Zoom and that means removing the noise and extraneous clicks that are exactly the signal that the detector puts out. Ugh! I wonder what other hidden features are lurking on my laptop hardware. I am conflicted because while I understand perfectly well why market forces compel hardware manufacturers to add these "features", I don't like the idea of not being able to trust my primary computing hardware.

imglorp 6y ago
A 10-bit ADC chip and a Raspi zero together cost under $10 on Adafruit. You would sidestep the audio card altogether.
- 0zelot 6y ago
  or one of those even cheaper 16bit USB soundcards https://github.com/ozel/DIY_particle_detector/wiki/Soundcards https://github.com/ozel/DIY_particle_detector/wiki/Soundcard... I believe Steve (who wrote the blog) might have had the wrong cable for his other computer (3-pin vs. 4-pin 3.5 mm jack)
shadowgovt 6y ago
Probably worth remembering that the sound card is generally designed to put out sound (or take in sound) for human perception. These "features" are features because they better map the physically raw input to the actual desired input for the most common use case. Sound is only sound because of human perception; if the hardware is sensitive to EM interference that the human ear isn't sensitive to, that's noise (literally).
analog31 6y ago
I've used the audio i/o hardware on mainstream notebook computers, and cheap USB audio adapters, for years, to perform audio signal analysis. This includes hardware purchased fairly recently. The audio subsystems contain the basic DC blocking and anti-aliasing features that you'd expect, but do not seem to add any other processing unless you ask for it (e.g., equalization). At least, nothing that would be noticeable in either steady state or transient analysis. So far as I know, apps like Skype and Zoom do their own processing.

imglorp 6y ago

A 10-bit ADC chip and a Raspi zero together cost under $10 on Adafruit. You would sidestep the audio card altogether.

0zelot 6y ago
or one of those even cheaper 16bit USB soundcards https://github.com/ozel/DIY_particle_detector/wiki/Soundcards https://github.com/ozel/DIY_particle_detector/wiki/Soundcard... I believe Steve (who wrote the blog) might have had the wrong cable for his other computer (3-pin vs. 4-pin 3.5 mm jack)

shadowgovt 6y ago

Probably worth remembering that the sound card is generally designed to put out sound (or take in sound) for human perception. These "features" are features because they better map the physically raw input to the actual desired input for the most common use case. Sound is only sound because of human perception; if the hardware is sensitive to EM interference that the human ear isn't sensitive to, that's noise (literally).

analog31 6y ago

I've used the audio i/o hardware on mainstream notebook computers, and cheap USB audio adapters, for years, to perform audio signal analysis. This includes hardware purchased fairly recently. The audio subsystems contain the basic DC blocking and anti-aliasing features that you'd expect, but do not seem to add any other processing unless you ask for it (e.g., equalization). At least, nothing that would be noticeable in either steady state or transient analysis. So far as I know, apps like Skype and Zoom do their own processing.