Nonlinear effects arising when narrowband noise acoustic beams propagate are experimentally studied. Special experimental setup allows radiating noise acoustic signals with specified characteristics and recording broad frequency range data as the signals propagate. The base of experimental setup is Ultrasound Measurement System Control Centre (Precision Acoustics) with the absolute accuracy positioning no more than 6 microns. Membrane PVDF hydrophone is used for acoustic field registration. The hydrophone is calibrated by manufacturer for frequency range up to 40MHz with non-uniformity no more than 20%. Radiator Olympus with Q factor near 3 is used for radiating noise signals with carrier frequency 2MHz. Typical acoustic pressure level at initial aperture is 1MPa. Experiments show transformation of signal spectrum to universal structure as the signal propagates. The law of spectrum falling in high frequency range is frequency in minus one power.
$^1$Federal State Budgetary Scientific Institution "Federal Research Center The Institute of Applied Physics of the Russian Academy of Sciences" (IAP RAS)\
$^2$N.I. Lobachevsky Nizhny Novgorod State University
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