I tried to use paplay to test something but that failed:
Code
LibreELEC:~ # paplay test_mono_44100Hz_8bit_PCM.wav
sndfile: Bad parameter passed to function sf_command.
Failed to determine sample specification from file.
So I collected some wav files around the net and tested them: Same result.
This is with OpenELEC 7.0.1 on a RPi 3.