Which term describes reference tones used to calibrate the level of sound, typically 1 kHz sine waves?

• A. Calibration tones
• B. Line up tones
• C. Reference tones
• D. Test tones

Answer: (B)

Line up tones are the specific reference tones used to align and calibrate the level through the audio chain, typically a 1 kHz sine wave. The idea is to “line up” every part of the signal path—from preamps and converters to monitors or meters—so they all respond to the same known reference level. This makes it possible to set consistent gain staging across the entire setup, ensuring that subsequent dialogue and music are measured and reproduced at the intended levels.

This term is the best fit because it emphasizes the action being performed: aligning or lining up the equipment to a standard reference. Other terms are broader or describe different ideas. Calibration tones can refer to any tones used to test or calibrate equipment, not necessarily the act of lining up a particular signal path. Reference tones and test tones are more generic descriptors and don’t inherently convey the alignment process across a chain.