Effects, Part 1

Effects — often abbreviated “FX” — come in various flavors, each of which is used for specific purposes. Some provide subtle sonic enhancements, while others supply exciting colors. This month we’ll take a look at some of the most important effect types. These days, effects are most often found as software in a computer-based DAW, but hardware effects are still an important component in well-equipped studios.

Most DAWs come with their own suite of built-in effects, which will cover the basics, but third-party effects software can provide higher quality or extend your sonic palette with entirely new types of processing. Third-party effects are a type of software plug-in. (For more on plug-ins, see the March ’06 What’s This For.)

To use an effect in a DAW, you insert it in a mixer channel, so that the signal in the channel passes through it. The signal could come directly from a microphone, or it could be a previously recorded track in a multitrack recording, or it could come from a synthesizer or other keyboard. Most keyboards have built-in effects to enhance their sounds, but after recording the keyboard you may want to add still more effects in the DAW.

EFFECT TYPES

The two most important tone-control effects are equalization (EQ) and filtering. EQ is more or less equivalent to the treble/bass tone controls on a stereo. It’s typically used for subtle shaping of the sound. Filtering is usually used to add a more active character to a track. A vocoder is a specialized type of filter bank that allows speech characteristics, such as spoken words, to be imprinted on another signal.

More active forms of tone control are seen in distortion effects. Distortion can warm up the tone without calling attention to itself, or turn the tone into a glorious grinding hash. Distortion effects include bit-crushing (which simulates the sound of older digital gear), waveshaping/overdrive, and ring modulation. An enhancer, which adds high-end sparkle, combines distortion and EQ.

Compressors, limiters, downward expanders, and noise gates are all dynamic effects. The most often used is the compressor, which produces an output that has a smoother, more even dynamic level by squashing the loudest parts of the signal and raising the quiet parts. A limiter prevents a signal from exceeding a user-specified level, which prevents the output from distorting.

The standard modulation effects include chorusing, flanging, phase shifting (phasing), and tremolo. Chorusing gives a sound a richer, more animated quality. Flanging and phasing introduce whooshing, metallic colors that rise and fall. Tremolo causes the sound to pulse, getting alternately louder and softer. A stereo panner is a special type of tremolo in which the left channel gets louder while the right channel gets softer, and then vice-versa. A rotary speaker simulator is a specialized modulation effect designed to imitate the swirling sounds produced by a rotating Leslie speaker.

The two time-based effects found in almost every DAW are delay and reverb. Aside from EQ, reverb is arguably the most important single effect in the recording engineer’s arsenal: It gives the illusion that the sound was played in an actual acoustic space such as a concert hall, stadium, or cement-lined basement. Reverb creates a large number of closely spaced echoes, which smear the sound and make it seem more “live.” Delay (also known as DDL, for “digital delay line”) adds separate, rhythmically spaced echoes to the sound. Delay effects are often synchronized to the tempo of the song, and allow the delay time to be set in rhythmic values such as eighth-notes.

USING EFFECTS