Control Bass, Treble, and Midrange in the Alexa App
You can use the Alexa app to adjust the bass, treble, or midrange for your Echo devices.
- Open the Alexa app 
.  -  Open Devices 
.  - Select Echo & Alexa.
 - Select your device.
 - Select Device Settings 
.  - Select Audio Controls and use the sliders to manage your settings.