Echo Sub volume level control.

[jimbode]

I have an Echo Sub paired with an Echo Show Gen 1    Near future it will paired with a Echo Show Gen 2

I found on many music sources the sub level is too high producing a booming effect.    There is no separate sub level control so I found what I think is a workable temporary solution.
The audio sent to the Sub appears  not passed through the Equalizer setting (Settings>Sounds>Equalizer) but the audio to the Show speakers is.
I found by setting all three equalizer sliders to about +80% to +90%  increases the Show volume but not the Sub.
Then  a little master volume down and it seems much more balanced with regard to the subwoofer bass level.   
I'm still trying on different sources.    So far I believe classical music seems to have less bass and can stand a boost.
For Sub boost move the three sliders to the left.
I believe its important to move all three including base to keep reasonably flat response across audio sent to the show.
I would like to see a Sub level slider on all music screens.   

[jimbode]

Thanks to Amazon Tech support for a partial  solution.    The Equalizer on the Echo Show indeed does not control the Echo Sub.
However the voice command   "Alexa set bass higher, lower, mainimum or maximum" do control the Sub level'
Also the Equalizer on the app also sets bass level .     
After much experimenting I conclude that the sub level is still to much too high.    Bass notes from a piano, base, Tuba etc. all sound uniquely different when playing the same low note.   That difference is in the harmonics or overtones characteristic of the instrument.   If the fundamental tone is louder than the harmonics the identity of the instrument is lost and the resulting sound is what is often called boomy.  And boomy it is.   The bass for the Sub needs to be cut back  such that the base notes sound instrumental.   Best would  be a separate Sub level control.   I believe this Sub has great potential an if Amazon does not provide this I plan to add a L-pad attenuater to the speaker.
I have for the time given up and I am using a bluetooth 2.1 system which produces plenty of hefty bass in good balance with upper tones.