Brahms, Piano Quartet op.60/i in C minor
Harmonic pedal has clear harmonic function. Dominant pedal prolongs the dominant harmony. It is functionally dissonant with (some of) the chords above it. Its power comes from the strong expectation of the reuniting of the bass and the other voices in the dominant, and their resolution into the tonic.
The long dominant pedal at the end of the development section in the first movement of Brahms’ piano quartet op.60 is a very powerful one. Although its power is charged on the listener’s expectation of the resolution, it’s harmonic pedal-ness is not the only parameter that forms its identity.
The pedal in m.176 emerges from the end of the quasi-theme (mm.142-176) in the middle of the development. The main material of the quasi-theme (mm.142-154) returns in mm.164-176 (in different key). Between them, there is a sort of fragmentary transitional section. The main material is open-ended: after the arrival on the tonic (too-early or too short to be considered the cadence), the tonic chord transforms into the dominant seventh chord, with which the following section begins (no real cadence). The moment when the dominant pedal enters, is comparable to the beginning of the transitional section in m.154. Although the material in mm.154-164 is taken from m.142, and the material in mm.176-198 is based on the second theme, the new section in m.176 is felt as another transition. The key was not really confirmed before m.176, although the pedal starts clearly on the dominant pitch.
Because of a possible relation to the quasi-theme that is just described, and especially because of the beautiful counterpoint that unfolds above the bass, the first reaction to this dominant-pedal section can be a feeling that a new section within the development section begins. The pedal-section is restless but not clearly directed to any aurally obvious goal. The first eight bars are in C minor, on the dominant harmony. Instead of resolving it to tonic (at least in the layers above the pedal) or starting another imitative cycle, Brahms suggests the sequence of the previous material, a major second up (m.184). The imitation of the motif, now in closer stretto, unfolds above A7 chord. From this point on, both harmonic rhythm, and melodic phrasing are faster, but the acceleration is not synchronized. This causes certain aural disorientation. After Eb7 harmony, a new imitative cycle begins on C7 (suggested F major key). Via chromatic line the last tonic chord (F-major in m.194) transforms into the double-diminished predominant (F#d.d.) to G-major chord. This progression is very implicative, the G-minor chord is un-doubtfully expected. The home key is re-established and the recapitulation may begin.
The dominant seventh-chords in the middle part of the pedal-section actively destabilize the home key. When the thematic material reappears as a sequence on A7 harmony, the home-key C minor is not necessarily kept as the anchor. In the foreground is the ascending sequence with gradually more complex counterpoint.
The pedal tone endures all the ‘challenges’, and the harmony finally returns to G-major. But before this moment, its harmonic identity is strongly subverted by the sequence that promotes other keys. In short, the G is not felt as the dominant. And while this might lead us to think that G is now more dissonant, and thus more strongly needs resolution, the effect of the series of modulations is a kind of alienation of the G, as a pitch that ‘doesn’t really fit’ the bass line. The truth is that G is not at all dissonant with the harmonies above it. It is actually a chord-tone in each of them; it is integrated in the harmonic progression. After being the root of the chord, it is the seventh, the third, and the fifth of the following ones. Only close to its end, the pedal tone becomes dissonant with the harmony that moves in standard progression towards uniting with it.
The pedal tone is thus consonant with all of the chords, and still dissonant in the context. What makes it dissonant is exactly the fact that it does not change. It does not follow the movement in the other voices. Although the chord succession is not perceived as one particular progression, all the voices move in a logical way to the next harmony. The sustained tone does not move; the other voices change and define its identity. Although it is the same tone, it feels as being always different. It is thus not independent from the other harmonic events, and it does not really suspend the harmonic progression (does not prolong the dominant). Because of this, its character as a pedal is somewhat ambiguous. Its harmonic pedal-ness is only at its beginning and at the end strong; in the modulating section its strength decreases.
What are then the other forces that make this pedal powerful? I believe that the growing tension is direct result of the growing of the pedal itself. The rhythmical repetition, in cooperation with crescendo from pp to ff, and the register (low G in the contra octave), works even on physiological level, as it resembles approaching of something big and (thus) strong. The raised tension prepares us to react to danger. We are in state of expectation: something will happen. This pedal is formed as an ostinato pattern. Melodic actors within the pattern strongly contribute to the intensification. It begins with the characteristic ‘sigh motif’, the core-motif of the piece. The ‘sigh’-interval grows progressively, first at slow rate, then faster and faster. Thus, two lines become established within the pedal-ostinato: the sustained pitch G, and the ascending line. The stretching of the melodic boundaries of the ostinato motif is felt as increasing of the conflict within the ostinato layer. The position with the most inner energy is G-F# interval, which is even more intensified by the appearance of Ab in violin. The resulting harmony is strongly implicative and the listener experiences strong expectation-tension related to the anticipated G-major chord, with the dominant function. Its appearance confirms the understanding of the sustained G as the dominant pedal, and the tension that is accumulated from m.176 is now projected onto the expected tonic chord. The deceptive cadence that once more stirs the emotions and colors the reappearance of the first theme, forms a wonderfully exciting opening of the recapitulation.
In conclusion, the unequivocal dominant pedal in the score, right on the place where it is most expected, is for its most part not working as harmonic pedal. The interaction between the sustained pitch, harmonic progression, and the organization of the thematic material undermines its potential pedal-ness. Its pulsating omnipresence in the low register transforms from harmonic function into the thundering sound in the background; the drone-ness increases. The overall growing of tension, together with the dynamicity within the ostinato pattern, and harmonic direction, gradually turns the sustained pitch again into the dominant pedal. The sustained pitch in the bass has, in its turn, united the sequential movement of the material, and intensified the energy they have created. In this way, the static G in the bass and the other musical processes intensify each other.
Brahms’ music is abundant in all the variants of pedal tones, some of them extremely long. In his Violin Sonata op. 108 in D minor, the whole development section unfolds above the dominant pedal. This pedal is not consonant with every single harmony, but there are many parts where it is on the local level quite comparable to the one discussed in this chapter.
 See Huron (2006).