"Denne Ultra-Subben er bygd for å prestere i Frekvensområdet 2-20Hz - MEN er avrundet på 8Hz slik at du trygt kan installere 2 stk. uten at hjertet ditt dør i området rundt 6 Hz" WTF?!!?
Danielsson et al. (1985) investigated the effect of LFN on blood pressure, heart frequency and serum cortisol. 20 male study participants were exposed to pure tones at different levels (95 dB, 110 dB and 125 dB) and frequencies (6 Hz, 12 Hz and 16 Hz) for 20 minutes in the first series of experiments. In the second set of experiments, a one-hour exposure (125 dB, 16 Hz) was followed by a silent control period. On alternate days, the same subjects were exposed to either infrasound (125 dB / 16 Hz) or a so called control exposure (50 dB / 50 Hz, just 5 dB above the mean hearing level). The one-hour exposure to LFN led to a significantly increased diastolic blood pressure and a significantly decreased systolic blood pressure in comparison with the control exposure. No significant changes of the heart rate and serum cortisol were obtained. Landstroem et al. (1983) exposed 10 normal hearing and 10 deaf subjects to 115 dB / 6 Hz for 20 minutes. In normal hearing volunteers changes of EEG patterns - interpreted as diminished wakefulness -, alterations of systolic and diastolic blood pressure and of heart rate were observed. These effects were not found in deaf persons. No differences in vibrotactile sensation were detected between both groups. Therefore the authors attributed the observed physiological effects to cochlear stimulation. Karpova et al. (1970) obtained the following physiological reactions caused by 15 minutes exposure to 5 Hz and 10 Hz simulated industrial infrasound (100 dB and 135 dB): significantly decreased respiration rate, "depression of the encephalic haemodynamics", changes of EEG patterns, increased heart rate, reduced heart muscle contraction strength. Wysocki et al. (1980) reported on tendencies of decreased heart rate, diminished electrical conductance which may result from the peripheral vascular changes and reduced skin temperature. 40 subjects were exposed to a low frequency spectrum typical for vehicles (control group: 20 subjects, no exposure). Evans et al. (1972) recorded vertical nystagmus and described a subjectively reported "feeling of body sway" in 25 subjects exposed to pure tones (2 Hz - 10 Hz) above 130 dB. The effects were primarily pronounced at 7 Hz. The authors developed a threshold curve for vertical nystagmus induced by a 7 Hz binaural signal. No level of the infrasound (1 Hz - 20 Hz / 115 - 120 dB) caused any visual disturbance. Takigawa et al. (1988) examined the influence of infrasound (5 Hz and 16 Hz, 95 dB, 5 minutes) on the control of upright standing posture. The authors concluded that the excitability of the vestibulum seemed to be accelerated by LFN, whether or not the subjects perceived any sensations. Doroshenko et al. (1983, methods see above) reported on significantly abnormal findings regarding the vestibular functions in the exposed group (test of statokinetic function, calorific test, rotational test). Waye et al. (2002) exposed 32 subjects to a low frequency noise and a reference noise with a flat frequency spectrum at the same A-weighted sound pressure level (40 dB(A)). For the LFN, sound pressure levels in the frequency region of 31.5 Hz to 125 Hz were added. Higher cortisol levels (six saliva samples during the two-hour exposure) were associated with high sensitivity to noise and being exposed to LFN (significant interaction). This association was not found for the reference noise.