Cause And Solution

-drop d tuning,high to low: eBGDAD-

Clean Riff,First Time:
e [---------------------15-]
B [-----------------18-----]
G [-15--15--15br--17-------]
D [---17--17----17---------]
A [------------------------]
D [------------------------]

Clean Riff,5x:
e [-----------------------------15-]
B [-------------------------18-----]
G [-15br--15br--15--15br--17-------]
D [-----17----17--17----17---------]
A [--------------------------------]
D [--------------------------------]

Clean Riff,Last:
e [--------------]
B [--------------]
G [-15br--15br---]
D [-----17----17-]
A [--------------]
D [--------------]

Distorted Riff: x2 (and x4 at the end)
e [---------------------------------------]
B [--------------------4-4-4-4br--4--/555-]
G [-5-5-5-5br--5--/333--------------------]
D [---------------------------------------]
A [--3-3-3----3-3-------3-3-3----3-3------]
D [---------------------------------------]