I had the same issue but found that I needed to increase the mixer setting for “Playback” in addition to the “Speaker” settings that you show:
[attachment=0]Screen Shot 2018-11-14 at 18.21.12.png[/attachment]
I’m using a 4ohm speaker and find that the settings I have (the left-most Speaker setting is the same as the Playback one) work well.
