Signal properties of amplified speech outdoors

Phonetics is replete with studies about speech in quiet indoor environments. However, many speech events occur outdoors. Additionally, in the modern era, they are frequently amplified. The present study examines signal properties of amplified speech in an outdoor setting. Four speakers read a subset of the Harvard sentences over a loudspeaker using a wireless handheld microphone in a quiet soccer field outdoors in late summer of 2025 on a sunny day. Recordings for each speaker were taken simultaneously at 4 m, 8 m, and 16 m away from the loudspeaker, in addition to a recording directly from the microphone. Intensity measurements were taken using a sound level meter several times at each distance during each session. Loudspeaker volume was adjusted for each speaker to produce an average intensity of approximately 95 dB measured at 1 m away. The overall intensity drop as distance increases will be measured for each sentence, which is predicted by the inverse-square law to be approximately 6 dB each time the distance doubles. The signal-to-noise ratio will also be estimated for each sentence. These and other quantities will be interpreted in relation to speech intelligibility in outdoor settings.