Studio tricks

There are several fairly basic studio techniques for linking the kick drum and bass effectively. These have become fairly standard tricks, but they aren’t particularly obvious (particularly when they are done well), so I’ll review them for fun and profit. All of them make use of a compressor/limiter/gate with a side-chain insertion point, and the basic thrust of all of them is to control or enhance the interaction between the two instruments.

Ducking

This is probably the most standard of the techniques. In effect, it lowers the level of the bass when the kick drum impulse occurs, and then turns it back up again while the kick is not sounding.

	Figure 6a. Envelopes of kick drum, bass, and bass “ducked” by kick drum (see flow chart below).

	Figure 6b. “Unducked” and ”ducked” combinations of the two instruments.

	Figure 7. Flow chart for ducker. Bass signal is in compressed by envelope of kick drum. Use the fastest release time unless you want a really weird and disorienting bass reverse envelope.

Looking at the Figure 7, you can see that the electric bass signal is run through a compressor. The compressor will reduce the level of the bass when it gets too loud, under ordinary circumstances. In this case however, the bass signal is not sent to the amplitude follower (which controls the gain of the compressor). Instead, the signal from the kick drum is inserted into the side chain (or control path) of the compressor, so that it is the level of the kick drum that causes the bass level to drop. Set with fastest possible attack and release times, the compressor permits the bass to be mixed at high levels without obscuring the kick, and causing the kick attack to over-ride the attack of the bass. The result? A more intense rhythmic pocket with no increase in overall level.

Pitched kick drum

In this case, there is no actual interaction between bass and kick. Instead, by use of an oscillator (sine wave is typical but other waveforms can be used for really interesting effects), a pitched decay is added to a dry kick drum impulse. Take a look at Figures 8 and 9:

	Figure 8. Envelope of very dry kick (or click track?), the gate envelope derived from it and the mix of the kick plus the gated sine wave in combination.

	Figure 9. Flow chart of the above gated sine wave plus kick.

In this case, the kick drum is used to key a noise gate with a timed or slow release, and a sine wave is passed through the noise gate. Typically, its frequency is in the bottom or second octave (between 20 and 80 Hertz), and it can be tuned to the root of the key of the song. As a result, the kick begins to acquire some of the musical characteristic of the bass, and to have considerably more punchy and full bottom end. The length of the decay (or timed release) is critical to the character of the sound, and should be determined by the character of the song.

Tightening submix

This last technique is a technique for keeping marginal rhythm tracks much tighter in amplitude, and much more closely balanced, but without really affecting the overall sound much, except where levels sag. Kick and bass (and sometimes I have also mixed snare into this) are mixed normally. In addition they are gathered into an auxiliary submix (sometimes with a little hyped EQ on both top and bottom), then through a limiter that is really squashing them, and then adding this squashed submix to the overall mix a couple of dB below the direct kick and bass. Under these circumstances, the submix is only heard when either of the two direct tracks sags a little in intensity or level. The rest of the time, it is pretty well masked. The result? A kick/bass groove that feels tight, intense and focused, even if it wasn’t during tracking.

	Figure 10. An aux mix of kick and bass is heavily limited and mixed with the dry tracks a few dB below their level, to keep them really tight and punchy, even when the dry tracks sag a little.