Respeaker Mic Array v2 playback quality and AEC

Hi!



The Respeaker audio playback capabilities are limited to 16Khz S24_3LE which is a very poor audio quality (though the AEC is excellent).

Using the 48Khz firmware suffers from audio downgrade issues and the AEC is pretty bad.



In an effort to play decent audio quality music and capture voice with good AEC, I’m trying to output audio playback (music) to both the Respeaker Mic Array v2 (for AEC) and another device (Raspberry Pi 3B+ 3.5mm audio port) using ALSA (I do not want to use Pulseaudio to avoid consuming lots of CPU, last time I tried it worked but consumed 30% of CPU cycles minimum).



I’m using Raspbian Stretch Lite.



I have not been able to output to both devices using the ALSA route/multi plugins. Each PCM device (respeaker and raspberry) work separately but not grouped using multi.



Does anyone succeeded in doing so?



Would this work with the AEC (delay, etc.) if the audio is output by the Raspberry 3.5mm audio port?



Thanks for your help.