From a related site on Tunguska, I found this:
Repeated testimony of strange sounds before the event.
In terms of the speed of sound in Earths atmosphere, the reports of weird sounds in advance appear absurd. But they are entirely plausible as “electrophonic sounds” heard either before, or simultaneous with, the sighting of brilliant meteor fireballs up to 100km distant. Electrophonic sounds signify the direct conversion, by transduction, of very low frequency electromagnetic energy into audible sounds (through a medium that can be as simple as a gold tooth filling or a pair of glasses). Abundant reports of peculiar sounds in connection with meteors, auroras, earthquakes and even nuclear bomb tests are sufficient to substantiate the effect. The cause is most easily understood as a natural resonance of an extensive plasma discharge in the Earth’s atmosphere (or underground in the case of earthquakes). In the case of an approaching comet, the incoming body is electrified with respect to the Earth.
http://www.thunderbolts.info/tpod/2006/arch06/060203tunguska2.htm
Once, about 20 years ago, my dad, brother & I were out watching a meteor shower in the back yard. We saw a large streak go across the sky, and then explode in a shower of sparks that lit up the sky and ground. To say it was awesome is an understatement. Even though it was probably 10 miles high in the atmosphere, I could have sworn I heard a hissing sound as it went across the sky and then a “pop” as it exploded. But I knew that could not be so; the sound would need many seconds to travel that distance. This seems to provide an explanation.
When interviewed, many of the Natives that witnessed the Tunguska incident claim to have ‘heard’ it before they looked and saw it streaming in the sky.
About 25 years ago, I saw a relatively large meteor (or space debris) hit the atmosphere at what must have been a fairly low angle, because of how slowly it moved across the sky. As it burned up and fragmented, I could hear a quiet roaring sound, much like the flame of a gas stove or a propane torch. Pretty cool - wish I had it on tape...
I heard one 'sizzle' so loudly and clearly that I said as much to the people around me. Followed with "...of course I know that's impossible, but..."