Regarding the IsoAcoustics test results, here are some simple "back of the envelope" calculations. Below are the IsoAcoustics GAIA II NRC Canada test results.
The highest peak in the surface velocity with spikes is ~7.8e-6 m/s at ~280 Hz. Using the formula given by Siegfried Linkwitz (source) shown below, we can come up with some estimates of the resulting dB SPL.
Assume (1) the dimensions of the panel that was vibrating is 1.0 m × 0.5 m = area of 0.5 m² (it is assumed that the sound produced would be the same as that from a pulsating sphere of 0.5 m² surface area); and (2) listening distance r = 3.0 m in free space:
Volume velocity U = surface velocity × area = 7.8e-6 × 0.5 = 3.9e-6 m³/s.
Density of air at sea level, 20° C, q = 1.204 kg/m³
Frequency, f = 280 Hz
Distance, r = 3.0
Sound pressure p = U q f /(2 r) = 0.000219 Pa = 20.8 dB SPL.
Thus, from the speaker FR curve as shown in the IsoAcoustics measurements, the SPL produced by the speaker cones was90 80.5 dB [Edit: Forgot the 3 m listening distance correction, assuming the graph was for r = 1 m] , and the rough estimate of the sound from the panel vibration is 21 dB.
The highest peak in the surface velocity with spikes is ~7.8e-6 m/s at ~280 Hz. Using the formula given by Siegfried Linkwitz (source) shown below, we can come up with some estimates of the resulting dB SPL.
Assume (1) the dimensions of the panel that was vibrating is 1.0 m × 0.5 m = area of 0.5 m² (it is assumed that the sound produced would be the same as that from a pulsating sphere of 0.5 m² surface area); and (2) listening distance r = 3.0 m in free space:
Volume velocity U = surface velocity × area = 7.8e-6 × 0.5 = 3.9e-6 m³/s.
Density of air at sea level, 20° C, q = 1.204 kg/m³
Frequency, f = 280 Hz
Distance, r = 3.0
Sound pressure p = U q f /(2 r) = 0.000219 Pa = 20.8 dB SPL.
Thus, from the speaker FR curve as shown in the IsoAcoustics measurements, the SPL produced by the speaker cones was
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