If I'm playing quarter notes at anything above 120 BPM my palm muting just falls apart. I'm either not muting all the strings I need to, leaving some ringing out, or muting the one I'm playing and possible even ones higher than it. Could anyone show me some videos about palm muting technique? I think my biggest problem is that even when I can I use a fanning motion to mute with my palm instead of proper positioning, so before I get into that habit I really want help with this.