The raw energy of the album comes in part from spontaneity and experimental production techniques which give each track a unique sound. On ‘Cannonball’, in final rehearsals before recording, Josephine accidentally played the high note of the riff flat before correcting herself—a mistake which was incorporated into the song. To achieve the distorted vocal sound, Kim plugged her brother’s harmonica microphone into her Marshall. “There was quite a bit of feedback,” Kim recounts, “so I had to step in and out of the room to get just the right amount.” Kelley, anticipating possible downtime during the four-week recording session, brought her sewing machine to finish a quilt for her mother. Kim, hearing the whir of the machine, put a mic on it. “It’s the first sound you hear on S.O.S.—Zig-zag stitch” says Kelley, who gets an album credit for guitar, vocals, and Kenmore 12 Stitch. Kelley turned the Morse Code distress signal (▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄) into a guitar part, hence the name of the song. To get a more abrasive guitar sound, the band built what Jim termed ‘the vortex’ – “using sheets of plywood we laid a floor and assembled walls and a roof to make a giant funnel, with Kim’s amp at the big end and a microphone at the small end.” The tremolo-effect on Jim’s drums was achieved by sending his ambient room tracks into a Leslie Rotary Speaker. (The Prodigy later sampled the guitar and drums for “Firestarter.”) On ‘Do You Love Me Now’, Kim sang into the strings of a grand piano, using a brick to hold down the sustain pedal, to create an eerie reverb from the resonating strings. Kelley remembers, too, Kim’s singular approach to problem solving, “She thought the cymbals sounded “too new,” they were ringing too long after Jim hit them. She wanted to fuck them up… I was in the studio lounge sewing, while Jim and Kim dropped cymbals out of the second-story window.”