[Pt. III Proj.3] – A Bach Chorale- Exercise 3. 5. B: Chorale Harmonisation of J.S. Bach’s Cantata ‘Wachet auf, ruft uns die Stimme’ BWV 140.
[Pt. III Proj.3] – A Bach Chorale- Exercise 3. 5. B: Chorale Harmonisation of J.S. Bach’s Cantata ‘Wachet auf, ruft uns die Stimme’ BWV 140. Returning to the chorale harmonisation, working phrase by phrase, sing through each part to develop a feel for the shape of the melodies and the sense of movement towards and away from cadences. Then sing all the way through each part from beginning to the end. Reflect upon what the lines were like to sing. How did the differ? How were they the same? Every chorale harmonisation you look at will have has its own character indicating the boundless number of ways Bach employs the techniques of common practice tonality to create unique harmonisations of the melody. Let’s work through the harmonisation observing some points as to its composition. Annotate your own copy of the score as you go.
Phrase 1: Harmonically we have a temporary shift to Bb major at the first cadence, indicated by the An in the tenor part. This is a compositional choice made by Bach – another composer could have stayed in Eb and is an example of how Bach creates longer term interest and structure in his chorale settings by moving between different key areas, however briefly
Phrase 2: There is another temporary shift to Bb major at the end of this phrase and something unusual happens here. The A in the alto which would conventionally rise to the Bb to effect the cadence, falls, and the Bb is in fact taken by the soprano. This is an instance of Bach showing us how rules are there to be broken. Though, for us, we must be vigilant that if we break rules we steer the right side of anarchy.
• There is a lovely use of suspension in this final cadence creating a sweet clash of the interval of a major second between the soprano and alto.
• There is a very interesting sound created on the 3rd beat of bar 9 produced by an accented passing note in the bass interacting with the harmony above it. A similarly interesting sonority happens on the 3rd beat of bar 3.
The range of the soprano voice in these first three phrases is unusually wide – spanning an octave and a third from Eb above middle C to high G. When composing in this way care must be taken so as not to create flimsy melody lines which are stretched too wide. However, we may speculate upon why Bach has chosen to do this. Might it be because here the music ‘paints’ the words which are about our being with angels singing God’s praises, wir sind Konsorten Der Engel hoch um deinen Thron, and the overall theme of the text is about watchmen high on the rooftops extolling us to wake up, Wachet auf?
Now considering the spacing of the voices, in general there are more shared notes, instances when the same note is sung by two voices at the same time, than one might expect in a Bach chorale. See how many you can spot in the entire chorale harmonisation.
There is a particularly noticeable instance of note sharing in b. 14 where a C minor chord appears in close position. This is a stark sonority which feels emphasised by the fact that the melody is in sequence, a repeated pattern, but the harmony is not.
Bach’s imaginative use of sequence here is an example of his boundless invention and how he does not rely on formula. It would have been much more obvious to have the harmony in sequence with the melody.
Even though there are shared notes in the chorale setting, there are no instances of part crossing – say, if the tenor were to dip below the bass. In general the voices are distributed evenly across the vocal range and seem to make space for each other. There is an instance of chromaticism in the bass’s melody which employs both a Db and a Dn in the same phrase. This creates a distinctive flavour for the phrase and the chorale setting overall.
Here the tenor voice takes over the crotchet movement from the bass seemingly in imitation of the previous bass part in b. 12.
There is an interrupted cadence V-vi to close the phrase.
Here the soprano melody is a repeat of the preceding phrase but it is reharmonised and the phrase cadences onto chord I rather than the previous chord vi.
The texture is also different from the preceding phrase. This reinforces what we find in Bach’s harmonisations in general: he prefers to do something new to reveal more about a musical situation than to repeat.
The bass line here imitates the soprano’s descent in the previous two phrases.
This means the cadence at the end of the phrase has a distinct sound, the bass falling from step two of the scale, the note F, to the tonic note, Eb, the cadence being a relatively scarce viib-I.
In phrases 4, 5, 6, 7 and 8 the parts seem to refer to each other’s melodies in imitation.
This creates a sense of consistency to the chorale’s texture though there is enough variety introduced to be constantly ear catching.
There are many other interconnections between the phrases in the chorale in general. Can you spot any of your own?
Of note here particularly is the drop in the bass, from Eb to An to facilitate a temporary modulation to C minor.
The interval Eb to A – the tritone – is reserved for special occasions in music of the period – going by the name of ‘the devil in music’ for many years prior to Bach’s use of it here.
C minor, appearing as a key or as chord vi takes a prominent role in the second half of the chorale harmonisation, including as part of the interrupted cadence V-vi in phrase 8.
Both the tonic chord, Eb major, and chord vi, C minor, contain the note Eb which is used extensively in the melody and which may partly explain the frequent appearance of chord vi.
Phrase 8: See Phrase 7
The melody is a repeat of phrase 3 but with a different harmonisation.
The phrase closes with a firm cadence onto Eb, establishing a sense of finality and completeness for the whole chorale setting by concluding firmly in the home key.