I thought I would share this and it works for this problem.Requires root which most of us have anyway.Hope this helps some with the same issue.
1. GO TO /SYSTEM/ETC AND LOCATION MIXER_PATHS.XML
2. OPEN FILE USING A TEXT EDITOR OR DOWNLOAD AN XML EDITOR FROM THE PLAY STORE.
3. SCROLL DOWN CLOSE TO THE BOTTOM AND LOOK FOR <PATH NAME="SPEAKER">
4. BELOW IT YOU WILL SEE THIS LINE:
<ctl name="RX3 Digital Volume" value="84" />
5. CHANGE VALUE FROM "84" TO WHATEVER YOU WANT, I RECOMMEND 90 - 95.
6. SCROLL TO THE VERY TOP OF THE SCRIPT AND FIND:
<ctl name="RX1 Digital Volume" value="84" />
<ctl name="RX2 Digital Volume" value="84" />
<ctl name="RX3 Digital Volume" value="84" />
<ctl name="RX4 Digital Volume" value="84" />
7. CHANGE ALL OF THESE VALUES TO THE SAME VALUE YOU SET AT BELOW.
8. SAVE CHANGES AND REBOOT.