I actually don’t want passthrough. I know it sounds a bit strange, but I want all my media decoded to PCM and played that way. The issue is that my AVR can only decode DD and DTS. The way I have things setup is I set high volume on my AVR and control the volume using the media center remote. Now, when I play movies with DD or DTS and passthrough, the audio is bit streamed and my speakers blare with full sound. I have to control sound using my AVR remote which doesn’t work anymore.
I rather have volume control in one place which coreelec. That is only possible either with LPCM or lossy transcoding. I prefer LPCM since my AVR can handle it. The last option would be to transcode even DD audio so there is volume control. I know it sounds crazy to decode a lossy audio for volume adjustment and then transcode to another lossy format :). But I prefer volume control over some loss of audio quality if it comes to it.
But to your point, I did try passthrough and 5.1 AAC audio still plays only through 2 speakers although I set the number of channels to 5.1.