Gate Your Way to Tighter Bass Grooves
By Anderton |
Lock your bass to the kick (or other drums) for a super-tight groove
By Craig Anderton
One of life’s better moments is when the bass/drum combination plays like a single person with four hands—and really tight hands at that. When the rhythm section is totally locked, everything else seems just that much tighter.
When you’re in the studio, several tools can help lock the rhythm section together. While they’re no replacement for “the real thing” (i.e., humans that play well together!), they can provide some pretty cool effects. Following is one of my favorites: a technique that locks bass to the kick drum so that they hit at exactly the same time.
Understanding this process requires using a noise gate, a signal processor designed to remove hiss from a signal. It typically has two inputs and one output. One of the inputs is for the audio signal you want to clean up, while the output is where the processed signal exits. In between, there’s a “gate” that either is open and lets the signal through, or is closed and blocks the signal.
The second input is a “control” input that senses an incoming signal level and converts it into a control signal. If the signal level is above a user-settable threshold, then the gate opens and lets the signal through. If the signal level is below the threshold, then the gate closes, and there’s no output.
Noise gates were very popular in the days of analog tape, which had a consistent level of background hiss. You’d set the gate threshold just above the hiss, so that (at least in theory) any “real” signal, which presumably was higher in level than the hiss, would open the gate. If the signal consisted of just noise, then the gate would close, blocking the hiss.
Most noise gates can do more than just simply turn the signal on and off. Other controls include:
Decay: Determines how long it takes the gate to fade out after the control signal goes below the threshold.
Attack: Sets how long it takes for the gate to fade in after the control signal goes above the threshold (good for attack delay effects).
Gating amount: his determines whether the "gate closed" condition blocks the signal completely, or only to a certain extent (e.g., 10 or 20dB below normal).
Typically, the control input senses the signal present at the main audio input. However, some hardware noise gates bring this input to its own jack, called a “key” input. This allows some signal other than the main audio input (like a kick drum) to turn the gate on and off. In today’s computer-based recording system, noise gates typically have a “sidechain” input which acts like a key input. A send from a different audio track can feed the sidechain input as a destination, and thus control that gate independently of the signal going through it.
Fig. 1 shows the basic setup. The kick track has a send bus, with one of the available destinations being the bass track’s gate sidechain input. Whenever the kick hits, the bass passes through the gate; if there’s no kick signal, the bass track’s gate closes and the bass signal becomes inaudible or reduced in level..
Fig. 1: The kick track’s Bus 1 feeds the PC4K Expander/Gate module’s sidechain input, which is shown as part of the Sonar ProChannel that's “flown out” from the Gated Bass track (track 3). Track 2 carries the unprocessed bass sound.
However, note there are two copies of the bass track, although you don’t necessarily need this. You may want to vary the blend between the gated and “continuous” tracks, or process the gated track—for example, send the bass through some distortion, then gate it and mix this track in behind the main bass track. Every time the kick hits, it lets through the distorted bass burst (which can be kind of cool). Another example involves adding a significant treble or upper midrange boost to the gated track. Whenever the kick and bass hit simultaneously the bass will sound a little brighter, thus better differentiating the two sounds.
Also note that the kick track send post-fader button is turned off, so the send signal is pre-fader. This means the send level is constant regardless of the channel’s fader setting.
Having the bass gated on/off can be very dramatic, but don’t forget about using gating to bring in variations on the core sound. Also remember this technique isn’t exclusive to the studio—you can gate live as well. Sure, gating is a “trick”—but it can add some really rhythmic, useable effects.
Craig Anderton is Editor Emeritus of Harmony Central. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.