One of the chief problems with kick drums, especially in modern electronica where deeper and deeper sub bass sounds
have become popular is the timbral masking that occurs when two sounds occur simultaneously (the brain will tend to only
hear the loudest of the two sounds in this case).

A really cool trick that we used to use back in Analogue recording days was to take a
31 band stereo equalizer and put the kick in mono on one side of the stereo equalizer and the
bass sound in the other.

Beginning at 30 hz you cut 3 db on the kick drum and raise the melodic bass sound by 3 db
at the next band (60hz) you do the exact opposite
in the next band you do what you did on the first band.

Physically , looking at the equalizer, the EQ looks like a zipper, each side alternately cutting and adding
3db.

Interestingly, if you solo each channel, the kick and the melodic bass sound will sound a little strange
but when you put them both center in the stereo spread, they will not mask each other anymore and yet they
will both sound full spectrum and distinct.

I love this trick and have used it on so many records.

Next question................who has a really good freeware simulation of a stereo 31 band graphic equalizer
(or an inexpensive shareware one)?

I so sensitive to timbral masking as a producer that I design kick and bass sounds specifically to be complementary with each other so I haven't actually used this techniques with electronic music yet.

******
by the way, the only problem with side chaining as advised earlier in this thread is that one sound will duck out when the kick is played and in a lot of dance musics, it's vitally important that the kick and melodic bass play on the same note.

This is especially important in breakbeat music where the kicks and the bass sounds won't be as timbrally divergent as , say, in Drum and Bass, or the kick as prevalent and unrelenting as in Techno.