The Impact Of Effects On Recorded Drums
Inserts & Sends
Once you’ve decided to use a real-time effect on a track, you need to “instantiate” it. (“Instantiate” is computer jargon for “create an instance of.”) The DAW owner’s manual will tell you how to do this; most DAWs let you select the effect from a menu (Fig. 1).
There are two basic ways to use effects: as inserts and as aux sends. An insert effect is applied to a single mixer channel. The word “insert” means that the effect is inserted directly in the mixer channel’s signal path, so that the sound passing through that channel passes through the effect. If you add several insert effects to a single channel, the signal will pass through one and then the next in a linear way (this is called a “series” routing).
Effects almost always have wet/dry controls. The dry signal is the signal entering the effect, and the wet signal is the sound that emerges from the effect itself. By adjusting the wet/dry mix, you can control how the insert effect is balanced with the dry signal.
An aux send effect is typically used to process the signals from several channels at once. Each channel will have a few sends — outputs that route the signal to an auxiliary (aux) bus. The effect is inserted on the aux bus, and processes whatever signals are sent to that bus from various channel sends. Each send is in the form of a level control, so you can send each sound to the aux effect at a low level or a high level.
By sending a signal from one channel to several aux busses, you create a parallel routing, in which the same dry signal is processed by several effects. The outputs of effects in aux busses are usually set to 100-percent wet because the output of the original mixer channel (the one whose sends you’re using) provides the dry signal.
Most often, you’ll use insert effects for tone-altering processes like EQ and distortion, and for dynamics-altering processes like compression. There’s generally no reason to apply these to several channels at once. Send effects are more commonly used for reverb and delay lines. For example, you may want to send several instruments through the same reverb to create the impression that they’re all playing in the same concert hall.
Why not just insert an identical reverb on each channel? Because that would make editing more difficult — if you needed a bigger reverb sound on the mix, you might have to edit the reverbs on as many as a dozen channels. But the main reason is because reverb in particular can use a significant amount of your computer’s CPU power. You’ll be able to play more tracks and use more software instruments and effects if you use only a single reverb where it’s practical to do so.
Effects can also be inserted on the master output bus of the mixer. The effects used most often on the master bus are EQ, which shapes the overall frequency contour of the mix, and compression or limiting, to ensure that the mix is as loud as possible without overloading.
Fig. 2 The graphic equalizer in Image-Line FL Studio 7 has 31 narrow frequency bands. The cut/boost is individually adjustable for each band. The frequencies of the bands are shown in the row below the band sliders. This particular EQ can morph among up to eight different presets, so you can do complex frequency-based modulation.
Equalizers are used to boost or cut the levels of signals within specific frequency ranges. If a snare doesn’t have enough snap, for instance, you can use an equalizer to boost the highs or high mids (see the Frequency Ranges sidebar). It will boost these same frequencies for everything else in that mixer channel. One reason for using multiple mikes on a kit is so you can EQ the most important drums individually.
A typical EQ effect has several bands. Each band may be locked into a separate frequency range. For instance, you may have a three-band EQ whose bands are dedicated to the lows, the mids, and the highs. Or you may have a multi-band EQ in which you’re free to choose the frequency range and bandwidth for each band (as in Fig. 1). This allows you to shape the sound with more precision. This type of EQ is called “parametric,” because it has three parameters for each band.
Each band of an equalizer has its own cut/boost control. You may also find a frequency control, which governs the center frequency of the band (the area where the cut/boost has the most power), and a bandwidth control.
A “graphic” EQ (Fig. 2) has more bands than a parametric EQ, but the only parameter you get to adjust is the cut/boost for each band. The bank of cut/boost sliders in a graphic EQ gives a rough idea of the frequency response curve of the effect; it’s called a “graphic” EQ because the sliders resemble a graph.
A filter is like an equalizer in that it’s designed to boost and/or cut the partials in certain frequency ranges. But the design is different. Filters often emulate the designs found in synthesizers. (See the section on Filters in my “Synth Basics” article in the March 2007 issue of DRUM!) A filter effect will usually have a built-in envelope follower. This tracks the loudness of the incoming signal (its natural amplitude envelope). The output of the envelope follower is used to raise or lower the
filter’s cutoff frequency. Filter effects with envelope followers can be useful with drum sounds because of the sound’s sharp attack and quick decay, but you may get the best results if one drum is well isolated from the rest of the kit.