Step 4. Patterns
By this stage you will normally have been able to complete a large portion of the exercise already, but there are likely to still be some larger gaps where it has not been obvious what to do, or which part to write the notes into.
The best approach is to look for melodic patterns which are already in the piece (preferably close by) and try to follow those patterns. Look at the size of the intervals used, and the direction of movement.
A large number of trios begin with imitation or a sequence in the upper parts. One part begins, then the second part plays basically the same music, or very similar music, starting a few beats later. You will lose marks if you fail to spot an opening with sequence/imitation, so always check to see if you can do it.
In this example, we have not yet managed to complete very much, apart from adding in a few roots:
At chord ①, we need a third. To work out which is the best part, look at the melodic patterns in bars 1-2. The top two parts have three-note figures, which rise by a 4th, then fall by a smaller interval. To continue this pattern, we would need to put the Bb into the top part:
If we then add the 5th (D) into the middle part below the G, we can begin another instance of the same figure (rising 4th) into chord ②:
The same approach can be followed in the top part for chord ②, and we can also fill in the rhythms to match. This is an example of an opening that begins with a sequence.
In this opening, we are not able to fill in much at all, and have a number of queries.
At ①, the chord needs a third (C#), but moving from F to C# is a diminished 4th so may not be the best solution (semiquavers (16th notes) normally continue as scales or arpeggios).
At ③, again we need a third (C#). While the C# seems ok at the point it sounds, there is another C# in the upper part, and we would want to avoid doubling the leading note if possible. This means we should be moving away from the C# before the end of this beat.
At ④, we already have two roots. We probably need a third (F), but the middle part would need to rise to the tonic for proper voice-leading (which it cannot do, because it would create consecutive octaves with the top part), or fall to the dominant as an emergency alternative, so this chord is also problematic.
To work out what to do, look at the top part and compare it to the opening of the second part. We can see that the first three notes are the same. Look at the bass part in bar 1 – the harmony across beats 3-4 is also the same as across beats 1-2, so we can simply copy the top part over.
Copy as far as possible, making sure that the notes fit the harmony each time it changes. In this case, we can also continue the top part a bit longer, just by copying. All the problems we had earlier have now been fixed: F moves to E (instead of C#), there is no doubled leading note at ③, and the mystery at ④ is now solved. This is an example of imitation – the second part echoes the first with the same notes.
Here is another example.
The 7ths, along with their preparation and resolution notes seem to be possible in either of the top parts. But is this really the case?
Looking at the figures themselves, you can see that there is a repeated pattern: 7-6-5, 7-6-5, 7-6-5. The bass line itself is changing pitch – it is moving up one step each time the figured pattern is repeated. This is a good clue that a sequence will work. We do not have much to go on in terms of melody, but notice that the top part has a 3-beat note which is tied over into the strong beat, and the middle part is showing the end part of tied note into a strong beat, which then continues by moving down by step. We can then assume that the top part might also continue by moving down by step:
We now know that the 7th at ④ (which is a G) must be placed in the middle part, along with its preparation and resolution notes, but which octave should they be in?
Looking at the sequence so far, we know that it starts on E (middle part, previous bar), then moves up by step to F# (top part first visible bar here). To continue the sequence, we should move to the G a step higher, rather than the lower G (which would be a 7th lower), at ③.
The sequence would start on A, another step higher, at ⑤.
All that remains now is to fill in the missing notes. The quavers (8th notes) move down by step to the 3rd of the following chord.