Method for acoustic adjustment using a loudness value and a clipping occurrence rate of a test sound source

A method for acoustic adjustment, which is executed by an arithmetic device including at least a preamplifier and an equalizer, the method comprising:

• setting an initial value of a gain value of the preamplifier based on a difference between energy of a test sound source before correction by the equalizer and energy of the test sound source after correction by the equalizer;
• amplifying a volume of the test sound source by the preamplifier using the initial value, calculating a loudness value and a clipping occurrence rate of the test sound source after a frequency characteristic of the test sound source is corrected by the equalizer, and determining whether a calculation result of the loudness value is less than a first threshold and whether a calculation result of the clipping occurrence rate is less than a second threshold;
• and
• reducing the initial value of the gain value by a specified value when the calculation result of the loudness value is equal to or greater than the first threshold or the calculation result of the clipping occurrence rate is equal to or greater than the second threshold.