Not everyone!
Check out the Function->Voluntary Control section here: https://en.m.wikipedia.org/wiki/Tensor_tympani_muscle
I tried to find stats on what proportion of people could do it, with claims of “a small number” through to “over half the population”.
This study says 55% in the general population. It’s also interesting as it’s exploring the ability to use this voluntary rumble as a control method for assistive technology.
Check out the Function->Voluntary Control section here: https://en.m.wikipedia.org/wiki/Tensor_tympani_muscle
Next time you yawn, listen for a low rumbling sound. Some people can do that voluntarily. Apparently 55% of the general population, but many people think you could train almost anyone to do it with some practice.