What is the instantaneous maximum audio level being processed at a given time called?

The term that describes the instantaneous maximum audio level being processed at a given moment is peak level. This refers to the highest level of audio signal achieved during a short period of time, which is crucial in audio engineering as it indicates the loudest point in the audio signal. Monitoring peak levels helps in preventing audio distortion that can occur if levels exceed the available headroom during processing or transmission.

Average level, while also important in audio processing, represents the mean level over a longer period and does not convey real-time extremes of volume. Root mean square is another method of measuring audio levels, particularly useful in assessing perceived loudness, yet it does not signify the immediate peak. Threshold level usually refers to the point at which processing may be applied, such as triggering compression or other audio effects, rather than to maximum level measurement. Thus, peak level is the most fitting term when identifying instantaneous maximum audio levels.