Re: Kick Drum ?
Not having a resonant head wouldn't make the drum any less loud, and if the kick is heavily muffled, as they usually are in old school open kick drums - since unmuffled single head kick drums sound like dog shit - it should sound punchier, with more thump, not less. Unmiced, and side by side with a kick with a resonant head, the headless one should seem louder, because of the extra punch.
Along the lines of what JR was saying, perhaps the subs weren't being engaged by the muffled frequencies, and that's why it sounded anemic in the PA.
A lot of sound guys use kicks more like triggers, so when the lowest frequencies go into a large diaphragm kick mic, the sound (which is not representative of the overall unmiced sound) comes out of the subs magnified to sound like thunder.
