Double concerto
Concerto for two solo instruments.
What it means
A double concerto is a concerto for two solo instruments and orchestra. The soloists can be of the same kind, for instance two violins or two pianos, or different, for instance violin and cello. The construction as a rule follows that of the solo concerto with three movements, but the layout of the solo sections is different: instead of a single counterpart to the orchestra, a conversation arises between two partners who pass material to each other, complement each other, and set themselves against each other.
Musical use
The genre extends from the Baroque, where it stands close to the concerto grosso, to the present. With soloists of the same kind, the appeal lies in imitation and mirroring; with different ones, in the difference of tone colours and ranges that the composer can exploit. For the writing it follows that solo sections are often more densely worked than in the solo concerto, because two voices are to be led. At the same time the orchestra must be treated differently, since two soloists claim more space. The kinship with the concerto grosso is founded historically and factually.
Performance practice
Rehearse first as a duo without orchestra and settle phrasing, articulation, and handling of time; differences in these points stand out immediately in ensemble playing. Decide who leads where, especially in imitations, and adapt tone colour and volume to each other. With unequal instruments, watch the balance, because one of the two usually carries more easily. Work out the transitions between solo and tutti with the conductor. Breathe together at entries so that the soloist group acts as a unit.
Bear in mind that the two soloists are perceived as a unit: differences in articulation, vibrato, and handling of time stand out more than with separate appearances. Rehearse therefore at length as a duo before the orchestra joins. Settle who leads in imitations and how the connection is shaped. Talk to the conductor about the strength of the accompaniment in the solo sections and breathe together at entries.
Position yourselves so that everyone hears each other and does not merely see the conductor.
Also check whether the edition offers a version with a second piano for rehearsal work.