If we could hear black holes, how loud would they be? I know that this is basically the same question as the question "How loud would the Sun be?", except this time there is a black hole. But since the black hole sucks in stuff like a passenger jet engine sucks in air, about how many decibels would it be? Also, would it lethal to humans if we were 1 AU away and what would it do to our planet?
Nothing comes out from the BH (well, with a single known, very small exception).
The accretion disk of the Black Holes most likely has various streams, pressure differences and so in it. Calculating it or measuring it is surely a very hard task, if you have luck, a professional explains the results in a better answer.
The accretion disc of the typical, star-sized black holes is much smaller as 1AU. And sound doesn't propagates in vacuum. Thus, from 1AU distance from the Black Hole we most likely wouldn't hear anything.
Other radiations (mainly gamma from the disc) may be deadly even from 1AU, but not its sound.
Physicists talk about phonons to describe energy transmission in elastic media similar to sound. There hasn't been much research about phonon transmission through the void of space because it is a forbidden event in physics. There is no sound in space. Some scientists have studied phonon tunneling through few angstroms of vacuum. https://physicsworld.com/a/phonons-tunnel-across-the-vacuum/
To find out more, you can read about phonons and sonic black holes.
Ears and microphones require air pressure and displacement of mass onto the auditory diaphragm. The mass and pressure of the interstellar medium is too low to actively move sound-sensing diaphragms, unless you have a lot of ions/gas massive objects to do that. In space there is a vacuum. if an astronaut played drums beside you in space, they would not displace any air pressure. there would be no noise.
If you had a 1000Watt studio speaker beside you in space, it's quite possible that you would receive less than a single electron worth of sound pressure energy from that speaker per m2. something like 10^-20 watts. 100 dB is about 0.01W/m2 and is at the limit of hearing impairment.
Do you know the warning: "In Space, No one can hear you scream"... the film aliens...