 The two takes of the song are performed at moderate , but somewhat different tempos . Both begin slower and speed up ; the first is about 106 beats per minute ( bpm ) , while the second is about 96 bpm . Johnson prepares to go into the fifth section for the slower second take , but the engineer apparently cut him off because of the time limits of ten @-@ inch 78 rpm records . In addition to the slower tempo , Johnson sings the verses at a lower pitch , although both takes are in the same key . This allows for greater variation and nuance in the vocal . Together with refinements to some guitar parts , the differences serve to help further distinguish the second take from " Terraplane Blues " and give it more of its own character . 
