The phrase "audible sound" refers to the sound that we can hear with our ears. It is the noise or vibrations that travel through the air and reach our ears, allowing us to perceive and understand it. Full definition
I'm already quite curvy and if my thighs are making audible sounds... it would just make me self conscious. (bylaurenm.com)
During my visit, conversation among the employees was the only audible sound. (theverge.com)
Bad gas will make an engine run rough and this can cause all kinds of vibration which can be converted to audible sounds throughout the vehicle. (mechanics.stackexchange.com)