Serge Auckland wrote:

I would love to try one of the ultra-low sub-sub woofers that work on
the variable vane principle. They should go down to 0 Hz
theoretically...you could dry your socks in front of one.......
but I doubt there's much actually recorded below 20Hz as current studio
mics don't go down below that.

You could try this sub:
http://www.bkelec.com/HiFi/Sub_Woofers/buttkicker.htm
Perhaps bolt it under your armchair.

I thought there were some organ recordings and that Telarc 1812
with sub 20Hz energy.

--
Eiron.