Unequal volume between internal and bluetooth

[myshkin-uk]

Just getting to grips with echo.
"Alexa please play rod Stewart" produces a sensible range of sound volumes.
Connecting a device (we tried two) seems to use a much lower range of audio volumes.
If we don't sort this out will mean ear-splitting volumes when we swap back from bt speaker function to Spotify.
Is there a setting to equalise these?

[mike27oct]

Each BT speaker I have seems to have it's own idea of preset "normal" volume.  Try other BT speakers.