Alright, I feel like stirring this pot again. I found a website that has a decent outline of what makes a band (or at least a song or album) "progressive rock"
, although I prefer the term "art rock" myself. Let's see how it applies to Pink Floyd.
1. "Long compositions, sometimes running over 20 minutes, with intricate melodies and harmonies." (like "Echoes")
2. "Many progressive rock songs are made up of shorter parts..." (like "Shine On You Crazy Diamond")
3. "Lyrics that convey intricate and sometimes impenetrable narratives, covering such themes as science fiction, fantasy, history, religion, war, madness, and literature." (like The Dark Side of the Moon
4. "Concept albums, in which a theme or storyline is explored throughout an entire album or series of albums..." (like The Wall
5. "Prominent use of instruments unusual in rock music, including electronic instrumentation, as well as unusual vocal styles." (they use synthesizers and the Mellotron as examples of unusual instruments (which I don't really agree with), and while a case could be made for how Syd played his guitar with weird objects, I could concede that this requirement isn't met)
6. "...Prominence of multi-instrumentalists..." (like Ummagumma
's studio side)
7. "Use of unusual time signatures, rhythmic techniques, scales, or tunings." (like "See-Saw" or "Money")
8. "An extremely wide dynamic range, with very quiet and very loud passages often occurring in the same piece of music." (like The Endless River
9. "Solo passages for virtually every instrument." (I'll concede here too, Rick and Nick didn't really get a lot of solo time to shine)
10. "Inclusion of classical pieces on albums." (not as far as I'm aware, as it refers to adapting actual pre-existing classical pieces and not writing original ones)
11. "An aesthetic linking the music with visual art..." (Pink Floyd might as well be pioneers of this, from album covers to live shows)
12. "The use of sound effects in compositions..." (again, Pink Floyd were the studio masters)
13. "Exchanging of members." (Tony Levin did play on A Momentary Lapse of Reason
, and Roger and David have played with a lot of different people in their solo careers... but I'll be willing to concede this point too)
That's 9 out of 13 for sure, 11 out of 13 if I stick to my guns. We're looking at Pink Floyd being between 69%-85% "prog", and that's good enough for me.