These explosions were recordered in the north-west of Mexico City on April 7, 2012.
This might be explained by fireworks.
The author’s comments:
My location was in the northwest of México City.
The second explosion is the strongest of all I heard, in fact resonated across the sky.
Notice how at 1:14 the third explosion triggered a car alarm.
It seems that the sound came from the south or above. These strange explosions occurred between 4 and 5:30 a.m.