Alarms and notification volumes are not set by voice. When you say, "Alexa set volume to 6" that only sets the volume for music and Alexa responses. For alarms, you need to go in the Alexa app on your phone > devices > Echo & Alexa > (select your device name) > sounds. There you will find a slider bar to set the volume for alarms, timers, and notifications. If you don't want to be blasted in the mornings, tick the option for Ascending Alarm to gradually increase the alarm volume.