From SYSTEM Sounds on YouTube:
The Black Widow pulsar (PSR B1957+20) rotates at a frequency of 622.1 Hz, producing a radio signal can be heard as an Eb note when converted into sound. The pulsar gets its name from the fact that it is slowly destroying its partner, using its wind to blow material off the surface of the brown dwarf. This creates a clumpy comet-like tail of plasma that passes between the pulsar and Earth every 9.2 hours. The tail acts like a giant magnifying lens (or amplifier) causing the series of irregular flickers you can hear in the pulsar’s signal. Is the brown dwarf trying to signal S.O.S.?