Size increases, standard group of 4 sections (strings, woodwinds in pairs- clarinet is new. Brass: pairs of horns, trumpets. Percussion: 2 timpani.) Note: trombones used in opera/church music. Composers expploited individual tone colors. Role of each section (strings most important; 1st violins with melody. Woodwinds add contrasting timbre; melodic solos. Brass adds power. Timpani for rhythmic bite and emphasis.