This will be a general guide because even within each speaker type listed, there are various changes that have been made throughout its life.
For example, a late ‘60s Celestion 25 watt G12M will sound different from one made in 1979 because the ingredients used in the creation of the speaker changed over time.
These are the classic ceramic speakers most widely known and available.
Celestion G12M Family, 20 and 25 watt "Greenback" The earliest G12Ms from the mid 1960s were rated at 20 watts and later increased to 25 watts RMS power handling capacity.
The old adage, "a chain is only as strong as its weakest link" can definitely be applied to the topic of speakers.
The trick is to play with the bass and volume control of the amplifier to careful find the right balance of compression.how much energy it can transfer to sound) of most G12M’s, are several d B’s (average 3-4) lower than many other speakers.The end result is that it is a quieter speaker (at the same comparative output setting on an amp) than others including the G12H or Vintage 30.A few d Bs in reduced sound output makes quite a difference!The G12M-25 watt from the late ‘60s through the early ‘70s are my favorite Celestion speakers for classic hard rock and blues tones, and the Heritage series 20 watt G12M reissue is also a fantastic speaker choice for this genre.