A 1 Pa peak-amplitude tone produces 91 dB SPL

Evidence

To illustrate the relationship between pascals and dB, we can use the stimuli in Figure 2–1 to determine the rms amplitude and dB SPL level. First, we assume that the peak amplitude in the waveform of Figure 2–1 is represented in pascals, and is 1 Pa. From Eq. 2–3, we can calculate the rms pressure as 0.707 Pa. Using this value in Eq. 2–4, we see that the dB SPL value of this tone is 91 dB SPL [20log(0.707/20 × 10−6) = 91 dB SPL]. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 208