Reverberation multiplies perceived speech loudness well beyond measured level gains

Evidence

Using the loudness exceeded 10% of the time as an indication of the perceived loudness, it can be expected that speech is about 1.21 times louder in the room with 0.6-s reverberation and about 1.78 times louder in the room with 2.5-s reverberation, in comparison with the loudness produced in open-air free-field condition. The increment in loudness is very helpful for the intelligibility of speech as long as the reverberation time does not produce temporal masking. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 2058

Categorization

• QUESTION: The 1.78× figure is specific — would be worth verifying the equations linking reverberation time to loudness increment and where the ceiling before temporal masking kicks in lies.
• XREF: Connects to loudness summation modeling in earlier chapters of this book (specific loudness vs time functions used throughout). — connects to: Reverberant fields supply most perceived loudness in normal rooms — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1776; Early reflections boost perceived loudness while loud late reverberation degrades intelligibility — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 273; A source’s changing directionality with frequency alters perceived timbre via the reverberant field — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1796 (+3 more)
• corroborated: 3 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 2058

Broader Connections

• Reverberant fields supply most perceived loudness in normal rooms #corroborates (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1776
• Perceived loudness does not map one-to-one onto acoustic amplitude #corroborates (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 616
• Early reflections boost perceived loudness while loud late reverberation degrades intelligibility #corroborates (0.80) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 273
• Perceived loudness of time-varying sounds tracks near-peak levels, not averages #corroborates (0.75)
• A source’s changing directionality with frequency alters perceived timbre via the reverberant field #expands (0.70) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1796