Bach Analysis: 'Brandenburg Concerto No.4'

Bach: Structure:

1.    The piece is in Ritornello form, a common Baroque structure.

2.    Small ritornello fragments punctuate episodic sections (bars 89-91).

3.    The orchestra have a background role during solo sections (sustained A bars 125-128).

4.    The ritornello appears systematically in all 5 keys: G, D and C majors; E, B and A minors.

5.    Alternative structural terms can be applied: Vordesatz (1-13); Fortspinnung 1 (13-22).

6.    Opening music is repeated in the tonic key in the final ritornello (345-427). 

Bach: Tonality:

1.    Tonality is linked to the home key (G major); modulations to related keys.

2.    Alternative terms: Vordesatz, Epilog and Fortspinnung can be applied to the piece.

3.    The head motif begins in G major, bars 1-13.

4.    The 1^st Fortspinnung begins in bar 13 (G major) and then modulates to D major (15). The tonic is avoided until 23.

5.    The closing theme (bars 79-83) is signalled by antiphony, hemiolas and staccato marks. Harmony is carried through a circle of 5^ths.

6.    Chain of dominants bars 125-136. 

Bach: Resources/PF:

1.    Concertino: solo violin and 2 recorders/side-held flutes; Ripieno: 2 violins, a viola, cello, violone and cembalo.

2.    Few dynamic markings. Light and shade is achieved by textural changes, e.g. strong tutti sound bar 14.

3.    Dynamic instruction shows awareness, e.g. pp in ripieno violins bars 235-251.

4.    2 recorders/flutes play in imitation (285-289) and antiphonally (257-263).

5.    Violin soloist shows virtuosic activity, i.e. elaborate string crossing bars 83-124.

6.    Ripieno violins and violas sometimes take over thematic material (129-132). 

Bach: Texture:

1.    4-part counterpoint (3 independent concertino parts over a walking bass) bars 13-22.

2.    Accompanied canon head simultaneously with elaborate solo violin passagework (198-208).

3.    Changing texture. Opening bars are homophonic; polarised texture (4-6) – gap between the melody and bass.

4.    Melody-dominated homophony in the bass line (1-12).

5.    Brief monophonic passages (84, 86, 88) and antiphonal exchanges (257-263, flutes).

6.    Heterophony between cello and continuo, bars 165-171. 

Bach: Rhythm:

1.    Triple time signature of 3/8 suggests 3 quaver beats per bar, however, more likely to hear a dotted crotchet rhythm at this tempo.

2.    1^st 12 bars introduce 3 rhythms: 6 semiquavers; 3 quavers and a quaver rest, and; 2 semiquavers and a quaver.

3.    Typical Baroque rhythms from bar 13, walking bass line below soloists continuous semiquavers. 5-note anacrusis effect.

4.    Rhythmic variety bars 35-56; all parts share semiquavers and the bass now has an articulated accompanying rhythm.

5.    Syncopated flute melody (43-46). Faster harmonic rhythm in accompaniment (67-78).

6.    The closing theme introduces hemiolas (79-82). 

Bach: Melody:

1.    Melodies are simple shapes based on scales and broken chords. Recurrent interval of a 3^rd (violin, bars 1-3) gives a likeness to all the parts.

2.    Melodic lines include arpeggio figures which underline chords, e.g. 2^nd recorder (1-2).

3.    Harmonically charged melodic lines in extended violin solos, e.g. violin (84) G major triad (83) to dominant 7^th of C major.

4.    Clear harmonic implications during scale based figures (bars 187-208).

5.    Closing theme introduces more angular shapes, including leaps of a 4^th.

6.    Use of sequence results in ‘super melodies’ that move slowly across long passages, e.g. phrase peaks (13-23). 

Bach: Harmony:

1.    Many diatonic passages. Accidentals are essential to modulations and belong to new keys.

2.    Bars 1-13 consist entirely of chords I and V. Bars 2-3 and 6-7 are perfect cadences but the phrases are dovetailed.

3.    Harmonic sequence (bars 13-18).

4.    Typical walking bass (14-19) single chord articulated per bar and leaps on and off the 3^rd.

5.    Varying harmonic rhythm. Very slow (35-42); 3 chords per bar in the closing theme and rapid chord changes around a circle of 5^ths.   

6.    Frequent dominant 7^ths, e.g. closing theme introduced by V7D (bar 78).