Idée Fixe

What is an Idée Fixe?

Idée fixe (French for “fixed idea”) is a term used by Berlioz in his Symphonic Fantastique and other pieces to describe a recurring theme in a piece of music that depicts a person or emotion – it is effectively the composition technique that is more commonly known as a leitmotif.

Hector Berlioz

The Idée Fixe in Symphonie Fantastique

Berlioz’s Symphonie Fantastique (1830) is an orchestral work inspired by Berlioz’s unrequited love for an an Irish actress Harriet Smithson (whom he later married!).
The idée fixe is a melody that portrays his love for the actress and it recurs in various forms throughout the 5 movement piece to depict how his unrequited love is expressed in various settings.

Reworking the Melody

Here are 3 examples of how the melody is reworked throughout the Symphonie Fantastique:

First movement – “Reveries – Passions” (Dreams, Passions)
In this 1st movement, the Idée fixe is introduced. It takes the form of a sweeping melody that evokes the longing and love that Berlioz is feeling:

Berlioz Dreams idee fixe

Berlioz Dreams Idee Fixe

Second movement – “Un bal” (A Ball)
In the 2nd movement, the motif is altered to be a waltz in the time signature of 3/8 and is much more decorated rhythmically to portray his unsettled emotions which he is struggling with despite being at a supposedly celebratory and joyous event:

Berlioz A ball idee fixe

Berlioz A Ball Idee Fixe

Third movement – “Scene aux Champs” (Scene in the fields)
In the 3rd movement, the music is a much slower tempo (adagio) as Berlioz contemplates his mixed emotions of hope that he will be with her, but the loneliness and sense of fear that he may not. This reflective mood characterises the return of the main theme played by a solo flute and violins, this time in 6/8 and with a slow tempo:

Berlioz Scene in the Fields idee fixe

Berlioz Scene aux champs Idee Fixe

In his Symphonie Fantastique, Berlioz showed that he was a master of reworking a main melodic idea to capture an emotion (his unrequited love for Harriet) in various different scenes and settings.

Whilst this concept is now mainly explored under the title of leitmotifs, Berlioz’s work is extremely valuable to composers who want to develop their craft. The ability to be able to adapt a melodic idea to depict different emotions, moods and places is one that will always be of considerable value.

It is certainly worth listening to the work in its entirety to see how Berlioz develops his idée fixe.
Here is a performance by the Orchestre philharmonique de Radio France conducted by Myung-Whun Chung: