His orchestral music is complex and colorful with more than a hint of impressionism in it. He composed 7 symphonies, many tone poems, and other pieces for orchestra as well as chamber, choral, and solo piano music. He was a fine pianist, but very rarely was on the concert platform.
His Symphony No.6 was written in 1935 and premiered later that same year. It was Bax's favorite symphony. Formally it is in three movements, but there are two sections in the opening movement and three in the final movement. The symphonic music of Bax shows his skill with the orchestra and use of materials as well as good, original material to begin with.
I. Moderato - Allegro con fuoco - The symphony begins in C-sharp minor with the bass trombone playing an ostinato figure:
II. Lento molto espressivo - The themes of this movement are related to the material already heard in the first movement. An interesting variant appears over a steady beating accompaniment a little over halfway through the movement. The movement winds down to a gently quiet ending.
III. The last movement is in three sections:
a) Introduction (Lento moderato) - A solo clarinet plays material that will be heard later in the movement. The strings enter with a variant of the clarinet theme that builds in intensity. Other woodwinds enter and play another motive until transitional material segues into the scherzo section.
b) Scherzo & Trio (Allegro vivace - Andante semplice) - The opening theme of the scherzo is a variant of the clarinet theme heard in the introduction. Other snippets of music resemble motives heard in previous movements. The trio moves gently through the orchestra, primarily in the strings. The scherzo returns with a vengeance and slowly builds to an impressive climax. The music slowly winds down and segues to the last section.
c) Epilogue (Lento) - A solo horn plays the clarinet theme over a delicate accompaniment of divided and muted solo strings, as well as the harp. The music slowly throbs with previous motives in colorful but subdued instrumentation. The music turns mysterious as it gradually dies away until it comes to rest in the key of C major.