The difference, by ear
Rock in Opposition began as an explicit alliance against prog's commercialisation, and its music is far more dissonant and less romantic.
Both are sung cleanly and move at much the same pace, around 60 to 180 bpm. Songs run longer in progressive rock: usually 6 to 20 minutes, against 4 to 12 minutes in Avant-prog / RIO. To hear the difference, play Henry Cow next to King Crimson. Avant-prog / RIO grew out of progressive rock, ten years later.
In figures
Avant-prog / RIO
Where it sits
Rock › Progressive rock › Avant-prog / RIO
In short
Rock in Opposition: dissonance, chamber music and left-wing politics. Prog that refuses on principle to be pleasant.
How it sounds
- Systematic dissonance and harmony drawn from twentieth-century chamber music.
- Unusual acoustic instruments - bassoon, violin, harmonium - alongside rock.
- Rigorously composed structures, without improvisation or melodic concessions.
Key acts
- Henry Cow
- Univers Zero
- Art Bears
Start here
The pickUnivers Zero - Heresie. Closer to Bartók than to rock.
Full page →Progressive rock
Where it sits
In short
Rock with classical ambitions: odd meters, twenty-minute suites, mellotron. The direct foundation of progressive metal.
How it sounds
- Odd meters - 7/8, 5/4, 13/8 - used routinely rather than as an effect.
- Mellotron, Hammond organ, Moog and later polyphonic synthesizers.
- Long suites, concept albums, sometimes a single piece per side of vinyl.
Key acts
- King Crimson
- Yes
- Genesis
- Rush
Start here
The pickKing Crimson - In the Court of the Crimson King. The first track tells you everything.
Full page →