Ah, that would explain a couple of things. I had the feeling the quality of SlimRio's playback wasn't as good as the original Rio code, but I had convinced myself I was imagining it. So all my 44khz files are actually being downsampled to 22khz

It also explains how Robin managed to "fix" the stuttering problem without a working tool chain.

I'll have to do some testing and see whether I prefer 128k MP3 transcodes or a 22khz sample rate...