Sounds like a laser going off, then a big rumbling explosion. Created in adobe audition using the generate tones to create a saw wave sweeping from 22khz to 20 hz, then reverbed and eq'd.
Recording of me flipping an electric switch in the bathroom, when i pitched down & went on to process it with weirdo effects, sounded off an explosion like that of a depth charge.
This is the first version of cannon. Wav. I tried to make a sort of explosion with my voice, and added a compressor, reverb and a little bit of distortion. Slow mo cannon. Wav was edited a bit more.
I took a gunshot, put a little bit of flanger on it and then rolled off the highs of an explosion and layered that underneath. I also added a few other effects to give it that fluttery sound in the end.