I will try to give a bit of perspective. Some of it will overlap.
HiFi Wiki is a pretty useful site for gaining an overview. It's in German but numbers are numbers and any reasonably educated English speaking audiophile should still be able get a basic understanding of what is there.
https://www.hifi-wiki.de/index.php/Canton_Lautsprecher
Very early on there was the LE series on top, and one lower level series whose name escapes me. From '72 to '75 the LE 600 was the top speaker, from '75 to '78 the larger LE 900 was top dog.
In 1978 the GLE 1st series replaced the LE's.
In1980 the Quinto line was started, replacing the early GLE series (note that there was/is a later GLE series that are completely different than the early ones) and ran until 1985.
The Quintos's were replaced with the Karat series starting in 1986 and subsequent models run until this day.
The GLE (1st), Quintos and Karats seem to have been the upper middle class but I'm not sure about what stood at TOTL from 1978 until the CT appeared. These series are all solid good performers.
In 1984 to 1986 the CT 1st series first appeared and was as far as I can tell 2nd tier TOTL. They ran until 1987/1990 depending on the specific model.
The CT 2nd series appeared starting in 1987, again there was some overlap.
The CT speakers are all high quality, similar to the Quinto and Karat but with better components (higher quality drivers and better crossover components).
On the other hand, there was/is the Ergo series. Aside from a single "Ergo" active speaker that was made in 1980-81 the Ergo replaced the CT models starting around 1990 as the TOTL speakers.
Sometime in the (late?) '80s(?) there were 2 Reference models, the 3000 and 6000. There is almost no information available about them but they have nothing to do with the later Reference series. A friend has a pair of the Reference 6000's and they are a fine little 2.5 way speaker (1x 25mm dome tweeter + 2x 6.5" mid/midbass).
The quality very small/satellite+sub sized speaker segment were covered with the GL lines starting in 1980. They were replaced with the Plus speakers starting in 1991.
The above are imho the best that Canton had to offer into the early 1990's. After the early 1990's I am actually not all that well educated about what was going on in the Canton world.
The Fonum series started in 1980 and was the entry/budget level of "full sized" bookshelf (and later on, floorstanding) speakers. These are reasonably good speakers but not up to the same quality level of the Quinto/Karat series.
The Nestor series speakers fit in there somewhere, but I am not at all educated about them, except to say that the very first Nestor active speaker appears to have been a TTOTL statement piece and only a handful of them were made.
I think that pretty much all of the other series cover budget, PC, small home theater market segments, at least until the early '90s, but there can easily be some little jewel that I have missed.
I hope that this is sufficiently confusing. We now return you to your regular programming.
James
