"Goodmans Audiom 51" is waaaaaay to wide a field to be able to answer this! Over the decades these speakers were produces, they were made with MANY variations! Some had cast frames, some did not ... some had smooth cones, some had ribs ... some used AlNiCo, some were ferrite ... some were true 15-watt max speakers, latter they were 30-watt.
"Goodmans Audiom 51" is waaaaaay to wide a field to be able to answer this!
Over the decades these speakers were produces, they were made with MANY variations! Some had cast frames, some did not ... some had smooth cones, some had ribs ... some used AlNiCo, some were ferrite ... some were true 15-watt max speakers, latter they were 30-watt.
Sooo ... narrow it down and maybe I can help!