A pedal point is a tone that is sustained throughout several changes of harmony. Depending on the changing harmony, the pedal point may be consonant with it, creating the impression of stability, or be dissonant with it, creating the impression of tension. Therefore, a pedal point is a device that composers use to sustain an impression of stability or tension, or to effect a sudden change of mood through the shift from consonance to dissonance or vice versa without introducing a distinctive new melody.
The use of pedal points is visible in the 1st movement of Mozart's Symphony no.41. Please refer to the Immerseel 2001 recording for time frame references. In this movement, pedal points are evident at 1:07~1:18 and at 8:34~8:44. Here, the violins play the melody which deviates from the key of C major in which the movement is written. In order to sustain stability and as a reminder of the movement's home key, Mozart wrote a long sustained tone in the dominant 5th for flute, oboe, horns and trumpets to pull the harmony back to its root into consonance.
Several pedal points are used throughout Beethoven's 5th Symphony, but the most significant of them is its use at the end of the 3rd movement. Please refer to the Gardiner recording. From 6:45, there is a great sensation of stillness, with almost no activity. This is when the timpani sounds out the pedal point on C, the violins on C, the violas on E, cellos on Ab, and bass on Ab. Then the violins switch to E, the violas to C, and the cellos and bass to G. All of these notes are tonic, dominant, or subdominant notes of the C major scale, in which the final movement is written. Thus when the brass instruments strike out the theme of the final movement in continuum of the pedal point tones, the sensation of triumph and completeness is immensely amplified.
A syncopation is "a disturbance or interruption of the regular flow of rhythm": a "placement of rhythmic stresses or accents where they wouldn't normally occur." It is usually used as an element of surprise or to create variety. According to encyclopedia Britannica, a syncopated melody's disruption of the listener's expectations arouses a desire for the reestablishment of metric normality, thereby acting as a "forward drive" for the music.
The entire minuet part of the third movement of Mozart's Symphony no.40 is dominated by syncopation. Please refer to 0~1:18 of Mackerras 2007 recording of the symphony. In this minuet, syncopation is achieved by sustaining the note on the third beat of one bar onto the first beat of the next bar. Therefore, instead of the first beat being stressed as under normal metric, the third beat of every bar is stressed. The sensation of falling onto the first beat of the following bar of melody through the note that is sustained over the bar line creates a drive to progress forward.
Heavy use of syncopation is evident the final movement of Beethoven's 5th symphony. Please refer to the Gardiner recording. For example at 0:07~0:15, where the piccolo, flutes, oboe, horns, trumpets and violins progress in eighth notes the first note of that progression is a continuum of the previous beat, stressing the 3.5th beat of those bars which would normally be a weak beat. The sensation of falling onto the progression of eight notes intensifies the already progressive melody with the progression eight notes increasing in pitch. This intensified sensation is suitable to the overall mood of the melody that seems to carry the theme of ultimate triumph.
Non-conventional Orchestration Decisions
The symphonies of the composers we are discussing make some orchestral decisions that are non-conventional, and perhaps these decisions widened the scope of the apparent expression of the inexpressible for the composers. Perhaps quite common in the more recent periods, but abnormal at the time of Mozart was the decision to start the...