Recording live ammo.
I’ve had a couple opportunities to record supersonic ammo from assault rifles. Here’s what I learned from recording guns:
The best recordings we were able to get were a PZM 50′ down range; a dynamic near the muzzle; a shotgun facing 180° to the gun about 40′ away; an XY 120′ down range perpendicular to the blast to catch flybys, and a lav taped to the post with the surface of impact.
Things 200′ or more away sounded great (probably better than any other mic) but the signal to noise ratio started getting iffy.
In our recording session we had about 14 different mics set at a number of different positions, and several different types of recorders. I wasn’t able to compare the transient quality of the various field recorder used (zoom H4s, Sony M10, zaxcom max, and sound devices 722 accurately) but the self noise isn’t an issue from any of the devices until you go beyond 120′.
Don’t use the built limiters on any of the devices unless you program in very specifically what parameters you want. The release times are usually designed for vocals and cause a ton of really bad sounding pumping.
Don’t worry too much about clipping on the transients. It doesn’t sound bad. In fact, it’s a quality people expect to hear with guns (not sure about cannons)
What it really came down to with us was you’re recording the gun in the space more so than the actual gun. (you’ll hear this advice from a lot of documentaries about this) There’s a sweet spot where you put your mics based on how much noise is in the environment where you get the best decays without starting to hear things like birds wind etc. and I think that comes down to experience recording guns etc.
Biggest advice is put up as many microphones as you can (even if it’s just your phone) and make sure everything stays rolling.