Second Movement (Largo) As is typical, Vivaldi’s Violin Concerto in G has three contrasting movements — the first and third vigorous and brilliant, the second gentle and slow. This slow movement is in basso ostinato (ground bass) variation form.

Our first impression of this music is probably of its texture and timbre — the gentle throbbing, the ingenious weaving in and out of the orchestral violins and the solo violin, and the delicate, subsidiary continuo sounds. There is, however, not much melody to listen to in the violin’s music. There is less, in fact, as the movement goes along and the texture changes.

Sooner or later we notice that the only real melody is in the bass, where a solemn, quiet theme (the ground bass) is heard repeatedly in the cellos and bass viol. The theme sinks down and down, ending with a strong cadence:

We develop a sort of double listening for music like this, listening simultaneously to the unchanging theme and to the changing material presented above that theme. (This is a little like taking in a distant view while noticing someone in the foreground.) After the theme’s initial statement, four more statements with violin variations follow, during which the solo violin plays faster and faster material above the unvaried ground bass. In its quiet way, this movement is showing off the violinist’s ability to play music that is fast and sleek.

After Variation 4, however, there is a marked stop. Variation 5 makes a grand contrast of the kind relished by Baroque composers and audiences. The continuo stops, and since the texture is now thin and ethereal, the ground bass (played by the orchestra violins) can be heard more clearly — and what we hear is that the theme itself has been varied. It is now in the minor mode.

The mood becomes muted and melancholy; the violin is now showing off not its speed, but its expressive capabilities. The mood deepens in Variation 6. Rather abruptly, after this, the original theme returns in the full orchestra and continuo, played just as it was at the beginning, to end the movement.

The construction of this movement as a set of variations over a ground bass exemplifies the thorough, methodical quality of so much Baroque music. The effect of the contrast that Vivaldi has added with Variations 5 and 6 is not diminished by the steadily repeating, even obsessive bass. On the contrary, double listening can make the contrast seem richer and more interesting.