What about sound conditioners?

[NYMorningstar]

I ran across this piece of equipment today that would take the low end and process the sound adding one octave to the bottom end. It kind of threw me because I had always figured if it wasn't there you can't add it. This piece would also add body an octave above. Anyone ever use something similar?

 

[moresound]

Are you talking about the peavey cosmos?
For I have heard of some using it on the kick drum track.

 

[mshilarious]

You can add lots of things that aren't there. Subharmonic content can be done with a relatively simple analog circuit, although it's much cleaner done digitally.

One thing I like to do is use pitch shift to drop the fundamental of my kick, because I have this little 18" cocktail-size kick. I wouldn't go a full octave though, that's too low. About a third down seems right.

 

[dementedchord]

dbx made one that's real popular with the rap set... cant remember the number right now but you find them in pawn shops all the time... pretty effective...