Because my iPhone doesn’t hold all my music, just some of it, I often find myself these days having to listen to stuff a few times in a day, because of going through a playlist in particularly heavy rotation.
Among others, I’ve been listening to U2’s Lemon today, and perhaps it’s a result of having particularly good headphones or something, but I can’t help but hear - and focus on - an unmistakable squeaking percussive noise, about once a second, starting at about 20″ in:
It doesn’t seem to be in precise time, and it sounds like a squeaky floorboard, which leads me to the inevitable conclusion/mental image that Bono, Adam Clayton or one of the other boys was recording his part while sitting in a rocking chair on a porch or something. Or a cicada got caught in the studio.
Listen to it and tell me it’s not the only thing you can hear. Distracting!

Ahh yes I hear it. The rocking chair does sound the most likely explanation, although, I’m sure they’d attempt to blame it on a guiro. Those thingies that you rub a stick along… I know what I mean!
Deffo a guiro - and it’s on a beat, not the but a beat. They probably got the bassist to lay it down to keep him interested during the long hours that Edge perfected his guitar
pedalsolo.(When I was in a crap indie band recording overnight - it’s cheaper - me and the drummer used to kill the many hours we were surplus to requirements while the guitarist and singer noodled by closing the door to the other recording rooms and running around madly in the dark bouncing off each other and the padded walls. The the drummer farted in a small sound booth and locked me in it, and ruined the whole thing.)
thats nothing if you listen to lamb’s “small” you can clearly hear a mobile phone going off 1.47 into the track. check it out:
http://www.last.fm/music/Lamb/_/Small