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The Allwinner H2+ and H3 CPUs are used in sub $20 and sub $10 boards such as some Orange and Nano PIs though they seem to be very different beasts sound wise fr

The Allwinner H2+ and H3 CPUs are used in sub $20 and sub $10 boards such as some Orange and Nano PIs though they seem to be very different beasts sound wise from the Raspberries. From page 61 of the Allwinner H3 CPU data sheet: ------ 2.1.8.1. Audio Codec - Two audio digital-to-analog(DAC) channels - Support analog/ digital volume control - One low-noise analog microphone bias output - Analog low-power loop from line-in /microphone to lineout outputs - Support Dynamic Range Controller adjusting the DAC playback output - Three audio inputs: -Two differential microphone inputs -Stereo Linein input - Two audio analog-to-digital(ADC) channels - 92dB SNR@A-weight - Supports ADC Sample Rates from 8KHz to 48KHz Support Automatic Gain Control(AGC) and Dynamic Range Control(DRC) adjusting the ADC recording input

makomk 7y ago
The trouble is, most of the H2/H3 boards seem to be designed as Pi-alikes and don't bother to wire up non-Pi features like line in. I'm not sure they'd even particularly benefit from doing so - not matter how useful the extra features are, all the hobbyist sites frame their discussion of other boards around how well they do the things that the Raspberry Pi can do, so chances are most people will never find out about what those other boards do better.
- squarefoot 7y ago
  That is true. Although the H2+/3 have a much better line output than the Raspberries and stereo line in plus differential mic in, on most boards the only input available is a mono mic one which is better than nothing, but a real stereo line in could turn out to be really useful. Actually, the mic input shouldn't pose any problems in some aplications, save for possibly higher noise than what could be obtained by pairing a quiet single stage preamp to a line input, however I wish board makers paid more attention to the audio world; with todays faster cores and cheap memory there are some killer apps waiting to happen. As an example, guitarix (http://guitarix.org http://guitarix.org) has been already ported to ARM, so a small board with decent audio i/o would make an ideal candidate for building a very compact guitar fx processor.

makomk 7y ago

The trouble is, most of the H2/H3 boards seem to be designed as Pi-alikes and don't bother to wire up non-Pi features like line in. I'm not sure they'd even particularly benefit from doing so - not matter how useful the extra features are, all the hobbyist sites frame their discussion of other boards around how well they do the things that the Raspberry Pi can do, so chances are most people will never find out about what those other boards do better.

squarefoot 7y ago
That is true. Although the H2+/3 have a much better line output than the Raspberries and stereo line in plus differential mic in, on most boards the only input available is a mono mic one which is better than nothing, but a real stereo line in could turn out to be really useful. Actually, the mic input shouldn't pose any problems in some aplications, save for possibly higher noise than what could be obtained by pairing a quiet single stage preamp to a line input, however I wish board makers paid more attention to the audio world; with todays faster cores and cheap memory there are some killer apps waiting to happen. As an example, guitarix (http://guitarix.org http://guitarix.org) has been already ported to ARM, so a small board with decent audio i/o would make an ideal candidate for building a very compact guitar fx processor.