Multichannel audio in Rockchip chipsets and ROCK Pi boards is impressive. I hope Radxa and others can take note of the possible uses for advanced audio projects, and work towards offering audio-focused hardware. Basic documentation and tested/working audio peripheral interface with Linux/ALSA drivers is key. A premium option with onboard audio oscillator and noise/jitter-reduction circuitry would further appeal to enthusiasts. ADC/DAC, physical interconnects, amplifier/PSU, etc, should be confined to addon boards (but Radxa reference addons would help kickstart the community).
Radxa forum confirms a high level of interest in audio. The top ROCK Pi S thread is “Audio Support Rock Pi S”. Raspberry Pi has a strong audio community, offering many HATs/amps/players, all limited by 2ch audio (one dedicated project even hacked 8ch). With the right approach, Radxa seems well suited to break into the scene.
RK3308 (Rock Pi S) supports 2x8ch I2S/TDM, 1x8ch PDM, 1x2ch I2S/PCM. However, RK3308 Ethernet prevents 16ch audio (I2S1_8CH interface shared with MAC). Maybe future chipsets will support simultaneous Ethernet and 16ch+ audio.
My particular use case is 8-16ch I2S output network playback device, headless - no video required.