Final answer:
The oboe typically tunes the symphony orchestra by playing a reference pitch that all other musicians use to tune their instruments to match.
Step-by-step explanation:
The statement that the oboe is the instrument that tunes the symphony orchestra before a concert performance is true. In an orchestra, the oboe typically plays a note (usually A440, the A above middle C at 440 Hz) that other musicians use as a reference to tune their instruments. This practice stems from the clear and penetrating sound of the oboe, making it an effective pitch standard for the ensemble. During the tuning process, woodwind, brass, and string players adjust their instruments to match the oboe's pitch. Fundamentally, different instruments, such as the trombone or the tuba, will use their own mechanisms—like slides or valves—to tune to the reference pitch provided by the oboe.