Sound enhancer from the Sprint-exclusive 'Harman/Kardon HTC One M8' (link)
Download this file and follow instructions. After flashing this, and flashing the adsp firmware zip, and disabling boomsound in the customize/ACC/default.xml, everything is working fine.
here's the post: http://forum.xda-developers.com/show...postcount=2810
it's a flashable zip which makes xml edits to enable harman sound and adds equalizer files.
I was wondering would this be safe / would it work to flash on our Verizon M8s??