I notice supercurio's result. There are artifacts(noise) between 22k and 44k range. This means the over sampling of WM8741 is not good. If oversampling works well, artifacts should go to higher range and removed by digitalflter easily.   WM8741 may not do interpolation at middle/high...

Dear Kingwa   How do you think about the following (red) point. I totally agree with Mr. Madwolf.   Quote: