MacBook Pro - Audio Volume on max not loud enough

When I plug in the earphone jack, for the moment the volume is great (as you would expect at max volume dialed), but then fraction of a second later it gets dumped down to unaceptably low.

I think it is a software issue, because it looks the volume is tuned down with fraction of seconds delay after the jack is pluged, rather then never present.

There got to be some settings somewhere to fix that. I am running 2.2 GHz INtel Core i7, 10.12.6