Me too. Here’s some thoughts that are probably wrong:
They’ve measured a supermassive black hole as spinning at 1/2 the speed of light. We’ll go with 150,000 m/s (wicked rounding there).
At first, I calculated the harmonic frequencies but unfortunately, at the VERY FIRST harmonic, you end up with the speed of light. Crud. Apparently can’t go any faster there.
So, a different tactic:
What’s another feature of black holes?
Gravity slows down time.
I’m thinking: Should you be able to get a monitoring instrument to record a black hole at JUST THE RIGHT DISTANCE away…
..you could find a “sweet spot”.
In that sweet spot, the apparent frequency of spinning would be slowed down enough by gravity’s time effect to bring the pulses (hertz) down to audible human range.
I could be wrong about this totally. Again, I’m thinking sweet spot. You’d have to be a particular distance away from the monitoring unit which would have to be a particular distance away from the black hole for this to work.
But at that sweet spot, where your location, the location of the “ear” and the spinning dark star, you could hear the song it sings.