Can sound distort the fabric of space?

[Andy SV]

Well yes but that is for what starts the explosion.
What does the edge of the expanding void do to space time as it sweeps up
The air and converts it to a dense shell of plasma. It probably contains a great deal of mass in a comparatively thin shell before it starts to implode.

 

[PeterDonis]

What does the edge of the expanding void do to space time

Not much in a practical sense. Even at 1000 times the density of ordinary solids, which is larger than the largest compression ratio I can get from the web site, the gravitational effects of the matter in the weapon would only be detectable by sensitive devices like torsion balances. Any analysis of the weapon's effects could assume flat spacetime in the weapon's vicinity as an extremely good approximation.