Conversations about Jaco Pastorius often drift into hyperbole and misinformation. Jaco could easily stretch a major 3rd (possibly more) and yet, in the lower positions, he used Simandl 1-2-4 whenever possible. Probably because he thought it
sounded better (the whole entire point of playing music).
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To the original point, Jaco became a great bassist by spending as much time as possible
playing with other musicians (especially those who were better than him or had something to teach him).