In response to WhatDoYouWantNow's comment:
In response to royf19's comment:
I've always defined Classic Rock as mid-'60s ('65 to '67 or '68) through 1989.
I tend to agree a lot more with RockScully's definition.
Though behind my position there is a decent bit of subjectivity. If you go all the way to 1989, you're including disco, punk, new wave.....all the way through bands like Nirvana, Alice in Chains, Guns n' Roses.
No way do I consider the latter three "classical", and I don't think I'm that old....
As you point out, heavy metal was just a progression from rock. Well a band like Alice in Chains is, if not still metal (Cantrell said he always considered it a metal band), a slightly further progression from it. It's simply "more metal" than metal - early Black Sabbath, but even rougher, louder, darker.
Nirvana is the farthest away from prior music out of the three, but they started up at the same time Alice in Chains was starting - 1987.
1975 or thereabouts seems like a pretty reasonable cutoff to me. You've got the first slew of rockers going into decline. You've got bands like Sabbath rising. You've got a slew of new genres gaining steam along with it. You've got the rise of the focus on the single. Not long after you've got MTV. Etc.
The reason I don't like 1975 as an end is that there were still bands that are generally agreed to be Classic Rock bands that were still in their prime long after 1975. That is why I'm a bit looser with my definition.
Two things to keep in mind too.
1. Regardless of what the time frame is for any of the designations, Classic Rock, Modern Rock, etc., not every genre in that time period IMO would fall under the Classic Rock label. I would never include disco or punk as Classic Rock.
2. Regardless of when you want to start and end any of the designations, it's going to be a bit fluid because nothing is ever cut and dry. While one era is winding down, new stuff has already been under way. That's why I like the 1989-91 period to end Classic Rock. There certainly were new things starting in the late '80s that fit in better with the 1990s, but there definitely were things ending around '89, '90 that fit in more with the 1970s than the 1990s.
One way to define the eras is having overlap in the starting end dates. For example I might start Classic Rock as early as 1962 with the start of the Beatles and the Stones and bring it all the way through to the end of the 1980s. Yet I might end oldies era after 1962 (around 1965) and start the Modern Rock era prior to 1990.
In any case, we're all free to define it any way we like. To me, I made the transformation from listening to Top 40 to album rock around 1979-80. So at that point there were a lot of bands from the 1970s that I liked, many of which started in the 1960s and that music was being played on album rock stations along with new rock that came out. And I liked/listened to current/new stuff throughout the 1980 -- stuff that was being played on album rock stations, which obviously was a lot of the hair metal bands -- Whitesnake, Guns and Roses, etc. When rock stations started playing stuff that was popular in the 1990s that's when I stopped liking new/current stuff.
You could see the transformation in this period with what rock stations were going through. Established album rock stations tried to bring in both listeners -- younger audiences who wanted bands like Nirvana or Alice in Chains, etc. along with their longtime audiences who like older stuff from the '70s and '80s. Those stations ended up losing audiences because the old crowd didn't want the new stuff and the younger crowd wanted more new stuff and less of the old stuff.
That's when Classic Rock stations began to emerge in the early 1990s. They catered to the older crowd, while other rock stations emerged that played mostly new stuff, occasionaly sprinkling in certain old stuff that fit their format.
So in the end, that's why I use the '89 to '91 period as the end of Classic Rock because it was right after that when stations ID'ing themselves as Classic Rock stations emerged playing pre-1990 rock.