The AKG 460 will respond down to a few hertz once the output
transformer is removed. Air blasts pick up quite well. If you have a DC
or 2 hz response of the playback system, you can watch the woofers pump
in and out as you move the mic forwards and backwards.

Makes for really tight and deep bass, just watch out for wind! (And
subways)

Jim Williams
Audio Upgrades