What is the purpose of reference tones used during production?

The purpose of reference tones used during production is primarily to calibrate playback equipment. Reference tones are standardized audio signals that help ensure that sound systems are accurately reproducing audio at the intended levels. By using these tones, audio engineers can adjust and balance the sound in various playback environments, making sure that the levels are consistent across different devices and setups. This is crucial in achieving a professional sound quality that maintains fidelity to the original recording during playback.

In contrast, while enhancing video quality, setting lighting for a scene, and generating audio effects are important aspects of production, they do not directly relate to the role of reference tones. Reference tones are specifically targeted at audio calibration, rather than the other functions described.