Fugue

Definition

a polyphonic composition based on one main theme called the subject

the subject is imitated by different voices throughout the fugue

the subject can be transformed in various ways:

1.  inversion: turned upside down

2.  retrograde: begin with the last note of the subject and proceed backward to the first

3.  augmentation: the original note values are lengthened

4.  diminution: the original note values are shortened

Answer: an imitation of the subject a fifth above

1.  real answer: a transposed restatement of the subject without alteration of intervals between successive pitches; implies a change of key (modulation)

2.  tonal answer: a transposed restatement of the subject with one or more pitches altered by a step; remain in the original key

Countersubject: a different melodic line that accompanies the subject

Exposition: the opening portion of a fugue where each of the voices enters and states the subject in succession

Episode: transitional passage between the various statements of the subject; nonimitative and freestyle

Middle entries: restatement of the subject after the exposition

Stretto: a subject is imitated before it is completed (from the Italian stringere, to draw close)

Pedal point (organ point): a single tone, usually in the bass, is held while the other voices produce a series of changing harmonies against it

1.  tonic pedal: a pedal point on the tonic pitch of the key

2.  dominant pedal: a pedal point on the dominant pitch of the key 

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Listening

J. S. Bach, Organ Fugue in G Minor (c. 1709)

Exposition

0:07  Subject enters in soprano

0:25  Answer in the alto voice, imitating the subject; countersubject in running notes in soprano

0:42  A short episode, featuring sequential repetition

0:46  Subject enters in tenor; countersubject in alto

1:03  Answer in the bass, imitating the subject; countersubject in tenor

 

Episode → Middle entry

An episode with downward sequence, followed by a return of the fugual subject (middle entry).

1:18  Brief episode, descendingsequence

1:28  Subject begins in tenor, continues in soprano, accompanied by sustained tone in bass

1:46  A brief episode, running notes in a descending sequence

 

Continuation → Ending

1:55  Subject in alto, major key; countersubject in soprano

2:10  An episode in major, upward leaps and running notes

2:21  Subject in bass (pedals), major key, countersubject and long trill above it

2:37  A longer episode, downward sequence; begins in major, ends in minor (circle-of-fifths sequence)

2:54  Recapitulation – Subject in soprano, minor key, countersubject below it

3:08  Most extended episode, running notes in a downward sequence; ascending sequences

3:36  Subject in bass (pedals), countersubject in soprano.

3:50  Fugue ends with the tonic major (Picardy third)