The Company of Biologists

Table 2.

Particle accelerations in three orthogonal Cartesian directions and for the magnitude of the three directions combined^{^*}

Frequency (Hz)	x-axis acceleration (m s^–2)	y-axis acceleration (m s^–2)	z-axis acceleration (m s^–2)	Magnitude of particle acceleration (m s^–2)
100	0.015	0.010	0.182	0.033
200	0.018	0.061	0.578	0.370
300	0.064	0.082	1.17	1.38
400	0.080	0.096	1.01	1.04
500	0.084	0.129	0.428	0.206
600	0.113	0.109	0.670	0.473
700	0.141	0.114	0.482	0.266
800	0.168	0.125	0.510	0.304
900	0.184	0.115	0.305	0.140
1000	0.219	0.124	0.362	0.194
1100	0.218	0.206	0.413	0.260
1200	0.168	0.249	0.339	0.205

Frequency (Hz)	x-axis acceleration (m s^–2)	y-axis acceleration (m s^–2)	z-axis acceleration (m s^–2)	Magnitude of particle acceleration (m s^–2)
100	0.015	0.010	0.182	0.033
200	0.018	0.061	0.578	0.370
300	0.064	0.082	1.17	1.38
400	0.080	0.096	1.01	1.04
500	0.084	0.129	0.428	0.206
600	0.113	0.109	0.670	0.473
700	0.141	0.114	0.482	0.266
800	0.168	0.125	0.510	0.304
900	0.184	0.115	0.305	0.140
1000	0.219	0.124	0.362	0.194
1100	0.218	0.206	0.413	0.260
1200	0.168	0.249	0.339	0.205

Sound pressure level (SPL) was measured by hydrophone, and mean SPLs of these recordings (in dB re: 1 μPa) were: x axis (116.7 dB), y axis (116.3 dB), z axis (119.7 dB). The x axis was considered to be anterior–posterior along each subject's body whereas the y axis was considered to be lateral (right–left)relative to the subject. Particle acceleration was calculated from the particle velocity measured by the geophone for stimulus acoustic sound pressures. The speaker was mounted in air 1.5 m directly above each test subject. Most of the acoustic energy was along the vertical (z) axis coming from directly above test subjects. The magnitude of particle acceleration (m s^–2) was calculated as√(x²+y²+z²)

(sensuCasper and Mann,2006)

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