Convention Paper
Equivalent Acoustic Distance
AES Convention 45 · Paper 911 · May 1973
Abstract
In certain acoustic environments, with no electro-acoustic system present, there exists a maximum path length between the acoustic source (talker) and the receiver (listener) beyond which meaningful communication and intelligibility suffers. When, for various reasons, listeners must hear at distance much greater than the maximum path length, it becomes necessary to use electro-acoustic systems. The goal of such a system is to provide at some distance much greater than the maximum path length described above the equivalent acoustic environment present at the maximum path length distance. That is to say, the electro-acoustic system must provide the loudness, tonal balance, and clarity present at the maximum path length when no electro-acoustic system is in use. The role of the signal-to-noise ratio, direct-to-reverberant sound, time delay of reflected sound, acoustic gain, and basic sound system configurations in establishing usable Equivalent Acoustic Distance (EAD) in real life sound systems will be discussed. A new all-inclusive sound system acoustic gain formula will be introduced as well as modifications to existing, widely used critical distance formulas.
