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Around 1968, the G12M became a 25w speaker and the label of the 15ohm version also changed to 16ohm at some point.G12M Blackback 25w 55hz The sound of the G12M tends to be very pronounced on the midrange, with a sweet, woody, warm and smooth sound.
It was also bright, lively and had a more restrained bottom end.
It’s simply a “generic” name that was given to the speakers of this period, similar to how “Plexi” is a name to all the pre-1969 Marshalls.
In other words, both the G12M and G12H can be called “Greenbacks”.
Speakers are extremely important when we are talking about tone. This article will be a (maybe not so) small post about the history of Celestion, as well as a brief description of each model they produced over the years. I’ll simply feature the ones that I think are the most popular and most widely used models. Early years and the G12 Al Ni Co Celestion started as a manufacturer of speakers for general use (radio, TV, etc.) back in the 1920s.
They give the amp its “voice” and so, in order to get the right sound, you will need to use the right speaker. In 1947, it was bought by British Rola and, one year later, production moved to Thames Ditton.