When I booked Earth for a college show some years back, I made off with a hand-written note that Dylan Carlson had left in the cafeteria. It read: "DO NOT PLACE ANYTHING especially BEVERAGES on or near this amp & equipment. You will be stabbed repeatedly and will be forced to pay for it if you live. Thank you." His cautionary screed still makes me chuckle, but I totally get where he's coming from: Earth's music is so deliberate, so sparse, so full of pregnant, between-beat inhalations that if the timbre of the guitar was even slightly off, the immersive, hypnotic effect of the whole song would be endangered. Earth's gear is a big part of their sound. So, y'know, stay the fuck away from it. 

[Northern, with Wyrd Visions, Broken Water, Angelo Spencer et les Hauts Sommets, 8 p.m., all ages, $10, 321 Fourth Ave., Olympia, northernolympia.org]