 Rounding out the genre, Saturday’s "Greasy Tracks" is steeped in Southern soul, but always manages to mix in late 1960s and early 1970s British blues stylists and extended acid jazz and fusion instrumentals.Since 2010, "Greasy Tracks" has presented an annual, single-day, Stax Records marathon of six or seven hours.The "Soulsville" special, believed to be the only program of its kind in the country, has featured interviews with 40-plus Stax-specific guests, including a veritable who’s who of Southern soul greats