7. How should the computer / tablet / smartphone be configured when the E18 is acting as decoder?

A: On smartphones, using a player with direct USB audio output (as per previous FAQ point) and then setting the volume to max on the smartphone may ensure bit-perfect output.  On a windows computer, one may configure the audio player to use WASAPI output to obtain bit-perfect output.  On the other hand, more sound processing options are usually available in “system sound” output mode (e.g. root-level android apps processing system sound streams), which may outweigh the benefit of bit-perfect output depending on your tastes.  Also, it may be difficult to control the volume using only the E18’s volume knob on sensitive IEMs / CIEMs using full digital volume bit perfect output;  in such a case it may be advisable to lower the digital volume as the gain in analog resolution (from the amplifier working in a wider range with the volume knob turned further up) outweighs the loss in digital resolution.