He told me the other day that he can create the illusion of bass.
I wasn't convinced at first but he explained that instead of using low frequences [20Hz - 150Hz] you can create a harmonic higher up at 150Hz - 1000Hz that tricks the ear into thinking that there's more low frequencies present.
This is called the 'missing fundamental': http://en.wikipedia.org/wiki/Missing_fundamental
This is achieved with a bit of hardware called 'MaxxBass'. [But I think you can actually get a VST for this.

Skip to 2:35 for the demonstration.
All in all, pretty impressive, halfing the peak size of your sub would give you a lot of room in the mix and throw a spanner in the works as far as the gain structure is concerned.
Anyone come across this before?

Maxxbass: http://www.waves.com/Content.aspx?id=327