There is simple melody dominated homophony texture
The trumpet has the tune, the trombone plays a simple bass line, and the horn providing harmony with alternating notes
Sometimes the top two instruments join forces in two part texture, eg. Bar 12, where they are in 6ths
Bar 25: Monophony, where the tune is shared between instruments
Bar 26: three part texture where the trumpet and trombone move together in two part counterpoint, while the horn has wide ranging broken chords
Bars 40-45: 'Oom-pah' accompaniment
In the last bar all the instruments move in octaves, in homorhythm
Structure
Very loose ternary form containing several short themes.
Section A: Bars 1-25/G major
1-8: Main theme modulating to D major
9-17/17-21: Faster subsidiary pair of themes
22: Return of opening idea but slower and with suggestions of tonic minor (gm)
Section B: Bars 26-57
26: New slower theme in E flat, played by the trumpet
30: The horn then takes over
34: The trumpet resumes the theme
39: A four bar linking section includes two octave leaps for trumpet, followed by a miniature trumpet cadenza
40: A further theme, related to the opening melody of the movement, in B flat
Section A (including 4 bar Coda): Bars 58-end
Return of the main theme in the tonic key (G). Music from the end of Section B (Bar 48) is then interpolated
73: The subsidiary ideas return
86: A short chromatic coda, the piece begins to gradually slow
Tonality
Fundamentally tonal
Frequent discords, which reduce strength of keys
Frequent chromatic notes weaken sense of key
Bar 86: scalic phrase in trombone
Poulenc tends to modulate to remote keys instead of closely related ones
The beginning is in G major
The middle is in the unrelated key of E flat (Bar 26), though there are a number of chromatic notes, including the A and B naturals in the trombone (26-28)
Bar 40: music in B flat
Harmony
Harmonies often quite bare
Last bar in octaves with no chordal notes at all
Bar 4: 'Simple' perfect cadences transformed by discord
Harmony often outlines by broken chords. At the beginning of the middle section (Bar 26) there is a first inversion chord of E-flat, with the horn outlining the root and fifth of the chord
Bars 86-7: trumpet plays B flat, sounding underneath the trombone's chromatic descent
Melody
Melodies are frequently simple diatonic tunes, e.g. main theme in G, Bars 1-4
Tune often outlines broken chords, eg. first three notes of the trumpet music
Occasional large leaps, eg. octave on Bar 2
There are occasional ornamental phrases eg. the grace notes in Bar 12
Conjunct music found e.g. trumpet Bar 4
Sometimes extends to more scalic music e.g. Bar 9
Rhythm and Metre
Principal melody contains mainly quavers and semiquavers, with crotchets for the cadence
Tunes often begin on the anacrusis (up-beat), eg. the first phrase
Bar 39: semiquaver scale in free rhythm
Bars 13-14: syncopation in upper two parts
Times signatures change frequently
Bar 39: 9/8 time signature, though this is a way of notating a bar of 4/4 plus a quaver anacrusis leading into next section of the movement
There are three bars in quintuple time (bars 17, 65 and 81
Speeds change frequently and are ofte used to differentiate between sections