I've never heard "equinox" pronounced with a short "e" before.
both are okay, and in the Midwest I always heard the short vowel (at least for the album title)
Main Entry: equi·nox
Pronunciation:
'E-kw&-"näks, 'e-kw&-Function: noun
Etymology: Middle English, from Middle French or Medieval Latin; Middle French equinoxe, from Medieval Latin equinoxium, alteration of Latin aequinoctium, from aequi- equi- + noct-, nox night -- more at NIGHT
1 : either of the two points on the celestial sphere where the celestial equator intersects the ecliptic
2 : either of the two times each year (as about March 21 and September 23) when the sun crosses the equator and day and night are everywhere of equal length