Katz, Murphy, and Farina reply: Please note that our article was an overview of research in virtual heritage acoustics, not a presentation of modern acoustical design methods. The letter by David Klepper focuses on electroacoustic solutions to difficult acoustic situations.

Contrary to assumptions by the letter writer, we are very familiar with energy-ratio metrics in room acoustics,1 including their limitations.2 Although not relevant for our introductory article, we have used energy ratios—together with other measures—not only for characterizing acoustic spaces but also for calibrating and validating acoustic simulations and auralizations.3 In particular, characterizations of Venice’s La Fenice theater4 and Paris’s Notre Dame Cathedral5 before each burned (in 1996 and 2019, respectively) inspired the name of the Past Has Ears (PHE, for the constellation Phoenix) project.

These days, other measurable quantities are often preferable to energy-ratio metrics and more reliable as refined design criteria, especially regarding natural room acoustics. For example, temporal and spatial energy-repartition measures, such as interaural cross correlation and lateral energy fraction, and the sound strength, or gain, are of growing importance in representing the quality of experience and preference among audience members, musicians, and actors alike.

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