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Table 1 Measured levels (dBA) and free-field predictions for acoustical survey sound sources, with source-receiver distances (meters)

From: The Huánuco Pampa acoustical field survey: an efficient, comparative archaeoacoustical method for studying sonic communication dynamics

Peak sound level measures for typical background noise level: ≈35 dBA; windy gusts: 50–70 dBA PUTUTU
Strombus conch shell horn (Lobatus galeatus)
WHISTLE metal/cork safety (proxy for Andean flute/whistle) CLAPPER
wooden percussion
VOICE
male; Quechua & Spanish speech (tenor/baritone range)
ESS (2^19)
repeated exponential sine sweep via mini loudspeaker
MEAS. (dBA) Free-field (FF) prediction MEAS. (dBA) FF pred. MEAS. (dBA) FF pred. MEAS. (dBA) FF pred. MEAS. (dBA) FF pred.
Characteristic frequencies 300 Hz tone;
harmonic peaks
≈610 Hz & ≈920 Hz
  3 kHz dominant tonal area (≈2.6−3.2 kHz)   broadband; esp > 1 kHz   Varies w/words; low-mid frequencies emphasized (≈150 Hz;  ≈350–450 Hz;  ≈500–600 Hz; ≈1.25 kHz articulation peak)   150 Hz–20 kHz (broadband) but low frequencies less robust due to loudspeaker  
 1 m calibration 96 dBA 105 dBA 95 dBA 75 dBA 90 dBA
Source (S1) at top-CENTER
 S1-R1 (7 m) 82 80 89 89 80 79 70 (audio) 59 76 74
 S1-R2 (14 m) 77 74 79 83 80 73 64 (audio) 53 71 68
 S1-R3 (25 m) 78 68 79 77 81 67 59 (audio) 47 62 62
 S1-R4 (27 m) 61 68 66 77 57 67 58 (audio) whispers understood 47 52 62
 S1-R5 (37 m) 58 65 60 74 57 64 45 44 53 59
 S1-R6 (64 m) 54 60 50 69 44 59 51 39 43 54
Source (S2) at E-wall niche overlooking plaza
 S2-R6 (43 m) 67 64 70 73 66 63 62 clearly understood 43 57 58
 S2-R7 (133 m) 51 54 60 63 45 53 39 33 43 48
 S2-R8 (225 m) 40 49 45 58 21 (audio) 48 34 (audio) 28 40 43
  1. Measurements below the sound level meter’s 30 dBA detection threshold were estimated from audio recordings where noted by (audio). Measured and predicted level data given here are graphed for visual comparison in Figs. 11, 12, 13, and 14