Someone asked me about how I did this technique so I am going to post a quick and dirty guide on how I go about getting this done. Others may have a variation or entirely different approach so, if you can, share your tech tips so we can improve, trouble shoot or get a bit of perspective on this elusive treatment to add that "oomph" to drum kicks.
I rarely use just one kick in my drum tracks and I use layering liberally. Here is my approach. This applies to the dance genre but I've used the same measure to treat the sub bass of acoustic drums as well.
-I get a kick that I really, really like and I make sure that it has the right length, volume and decay on it. We will call this Kick One. I don't add any effects at all to the raw kick sample.
-Then, I find a complementary kick (Kick Two) which closely matches my kick of choice but has a different tone that I like as well. I put this is a different track, grouped together with my main kick sample.
-Using a pitch shifter, I tailor Kick Two to Kick One, adjusting the pitch a few cents above and below the pitch of the main kick. I look for a sweet spot where both samples blend the best.
-Bounce the resulting track to EQ as one file.
-EQing: I normally EQ just one frequency bracket to do as less to the sample as I can but in cases where a bit of shaping is called for I target the following frequency bands: 20-60Hz for the sub-bass, 80hz or so for that fatness and warmth, 1-2khz and 20-30khz for attack and high end sparkle.
A general rule of thumb I use is: get as much of a good take as you can because fixing something at the board is something you shouldn't have to do. However, when you do have to EQ or shape something, take a minimalist approach and consider the entire context of the drum track to give it what it needs to become more cohesive. You want the drums to sit well in the track, not clash against it.