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Whats the diff b/w a fugue and an invention?

  1. Nov 4, 2015 #1
    I dont understand the difference. For example, the goldberg variations compared to the art of fugue. Are these both examples of fugues or are Goldberg variations not fugues. Is there a simple way to understand the difference or even better --to be able to instantly recognize a fugue from an invention, for a non musicians?
  2. jcsd
  3. Nov 4, 2015 #2


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  4. Nov 4, 2015 #3
    Fugues are generally unmistakable because they all begin in the same way, which is A.) The theme is played by itself starting on a given pitch, then B)The theme is played all over again, except at a different pitch. While it's played at that different pitch the first "voice" continues to play in a way that harmonizes with the second voice. Then C.) the theme is taken up by yet a third "voice" at yet a third pitch, while the first two voices continue to harmonize with it. Some fugues go on to add a fourth "voice."

    From there, things develop in complicated ways, but throughout you keep hearing the theme re-entering at different pitches while the other voices harmonize with it.

    Here is a kind of joke fugue written by Glenn Gould for 4 voices (It's a real fugue, but he intended the lyrics to be funny). It's actually sung, and has lyrics, which is why I point it out: it's easy to identify the different voices that way.

    Now here's Bach's g minor fugue on piano. Listen with an ear to catching the theme repeated at different pitches by all the different voices.

    If you listen to enough fugues you easily get to the point where you know it's a fugue as soon as the second voice enters, even if you haven't heard it before.

    As for inventions, the first three two-part inventions by Bach seem sort of like fugues at first, but they are different than fugues because the second "voice" repeats the theme at the octave, which never happens in a fugue. None of the other inventions have that form. The reason they're called "inventions" is because the composer invents the form rather than using some pre-existing form.

    The Goldberg variations are variations. It's hard to tell because they're unusual variations. He is varying some element of the base line instead of varying the theme, which usually makes variations instantly recognizable. The Goldberg's aren't good variations to use to learn what variations are.

    Here's a much more accessible example of variations:

  5. Nov 4, 2015 #4


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    I would like to change my answer.

    What Zooby said.
  6. Nov 4, 2015 #5
    You win The Tinhorn Fugue from Guys and Dolls!

  7. Nov 4, 2015 #6
    i can see how the mozart piece is variation after variation but the fugue in g minor more confusing.. to me it sounds like invention, based on it repeats that same theme octave lower. then later the theme is played higher, but its still fugue? great answer btw, but to be honest its still confusing to me.. but maybe its like this: you ask funk guy whats the diff b/w funk and acid jazz?....he can spot the diff right away but to the untrained ear.. no diff at all.. Seems like a complicated distinction (for fugues i mean)
  8. Nov 5, 2015 #7
    The fugue starts on g. The first repetition is on d below that, which is not an octave, but a fourth. The next repetition is on g below that d, which is a drop of a fifth. It doesn't drop or rise a whole octave from one repetition to the next anywhere.

    The inventions have first repetitions that drop an octave. This has a distinctly different feel than dropping a fourth or a fifth. (A fugue doesn't always drop a fourth or fifth, it can also raise a fourth or fifth on the first repetition. It won't drop or raise a whole octave, though.)

    If you're really interested in being able to hear the difference you should probably ignore the inventions for a while and just listen to fugues. If you have any kind of musical instrument around play fourths and fifths and octaves. You'll see they have a very different effect. Octaves sound kind of static: it's just the same note higher up. Fourths and fifths have more of a sense of movement to something different.
  9. Nov 5, 2015 #8

    If you want to sing along:

    Rah rah
    Ro mah
    Want your bad romance
  10. Nov 5, 2015 #9


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    Well, both were written by J. S. Bach who was an expert on fugues. In my opinion, fugue techniques and themes are part of most of his works, no matter what they are called.

    But - returning to the fugue. The simplest form of a fugue is the classic canon ( or round as it called in the UK). This is a simple device, somebody starts singing the song and after a line or so, others start singing from the beginning of the song (if this is confusing, a long explanation is here: https://en.wikipedia.org/wiki/Canon_(music)). The baroque fugue takes this concept and evolves it, using various transformations on the melody where the other voices join in (double time, half time, upside down, backwards etc). For a lengthy explanation, see https://en.wikipedia.org/wiki/Fugue.
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