ACOUSTIC TESTING BENCH FOR SOUND ABSORBERS Russian patent published in 2017 - IPC B06B1/00 

FIELD: testing equipment.

SUBSTANCE: acoustic testing bench for sound absorbers contains the metal case with the removable front lid, the walls of which are lined with the tested sound absorber, differs in that the adjustable noise source is set on the body bottom through the elastic damping gasket, besides, the adjustment is carried out according the sound volume and signal frequency, using the signal power amplifier and oscillograph, and at the distance of 1 m from the housing cover the microphone is fixed, the sound pressure levels signals from which go to the frequency spectrum analyzer, and then to the computer to process the information received, at that the sound power level L_p is determined by the measurements results of the average sound pressure level L_cp at the measuring surface S, m², which is taken as the hemisphere area: , where S=2πr²; r - the distance from the source center to the measurement points; S₀=1 m² and the corrected sound power level L_pA: , where L_Aav -average sound level at the measuring surface and value of the sound pressure level ΔL reduction in the sample reflected sound field the is calculated by the formula where L-sound pressure level at the calculating point up to acoustic treatment of the room, dB; L_obl -sound pressure level at the calculating point after the acoustic treatment of the room, dB, B- constant of the vessel cabin before its acoustic treatment, m²; B₁- constant of the room after its acoustic treatment, m², which is determined by the formula where where A₁=α(S_total-S_obl) - the equivalent area of sound absorption by surfaces, not occupied by the sound-absorbing lining;α= (B)/(B+S_total) - average sound absorption coefficient in the room before it is acoustical treatment; α₁-average sound absorption coefficient of acoustic treated room, defined by the ratio , where ΔA - the value of total optional absorption, made by the design of the sound absorbing lining or single piece sound absorbers, determined by the formula ΔA=α_oblS_obr+A_psn, where α_obl - reverberation sound absorption coefficient of lining design; S_obl - area of this design, m²; A_ps - the equivalent sound absorption area of single piece absorber, m²; n is the number of single piece absorbers in the room, differs in, that for testing the effectiveness of acoustic ceiling coated with sound absorber, remove the absorber from the metal body walls and the effective part of adjustable noise source direct to the ceiling part of the body and turn it on by subsequently changing the sound volume and the signal frequency, then send the signals from the microphone to the power amplifier, such as strain gauge, and send the signals from it to the oscillograph and record the oscillograms of the sound pressure levels, according to which determine the efficiency of acoustic ceiling.

EFFECT: expanded technological capabilities of objects testing, having several elastic couplings with the body parts.

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