Anybody know what the frequency of highest energy output is for the kickdrum used on the Clapton Unplugged cd is?

I did a walkabout of my apartment with this CD playing and the kickdrum did a great job of showing me where I have the greatest low frequency gain. The results were interesting.

Google is Cool: kick me

Cool graphic!

Thanks Mark, I've bookmarked that one. I would have expected a norrower range for the kickdrum.