Which instrument families are included in a modern symphony orchestra?

A modern symphony orchestra typically comprises four primary instrument families, which have evolved over centuries to provide a wide range of tonal resources. These sections are:12

• Woodwinds: This section generally includes flutes (often with a piccolo), oboes (including the English horn), clarinets (including the bass clarinet), and bassoons (including the contrabassoon).32
• Brass: This family typically consists of trumpets, horns, trombones, and the tuba.12
• Strings: The core of the orchestra, this section includes first and second violins, violas, violoncellos (cellos), double basses, and often one or more harps.12
• Percussion: This section is led by the timpani, which are standard in the orchestral repertoire, and includes a wide variety of other instruments such as cymbals, the xylophone, the celesta, and tubular bells, depending on the specific musical work.1245

While these four families form the standard foundation, the exact composition can vary based on the requirements of the composer and the specific musical era.12