The Earliest Black Sabbath albums where most likely recorded using Greenbacks and the mid 1970s albums like Sabbath Bloody Sabbath and Sabotage where most likely recorded using Goodman speakers. In this video I'm comparing a 1972 Celestion G12M25 75Hz Greenback to a 1976 Goodman Audiom 12P-G. I'm using a 1975 Gibson Flying V, a 2016 Pure Tone Amps Offset and Marshall 1933 cab for the comparison. Tony Iommi used Laney Super Group stacks and Gibson SG Special and Dallas Rangemasters modded for full range though. Check out the links below for more videos on that. The Laney Cabs had T1221, T1217 and T1976 Celestions. T1976 is actually the model that's most often suggested as Tony's Greenback in online discussions but compared to the Goodman they sound very similar.