Niall Magennis, Personal Computer World, Wednesday 17 September 2008 at 10:00:00
A lessing in flanging and phasing
Previously we've taken an in-depth look at audio effects and how you can best use them in your music. We covered distortion, delay and reverb. Here we’re going to finish off by taking at look at modulation effects such as phasing, chorus, flanging and pitch vibrato, while also touching on pitch shifting.
Whereas distortion, delay and reverb have an obvious ‘in your face’ influence on your audio, modulation effects tend to sound more subtle. Nevertheless, they are key elements of many types of music, including reggae, trance and 1960s-style psychedelica.
However, because the controls on modulation effects are often labelled with obtuse terms such as frequency, depth and rate, they can be a bit tricky for novices to get their head around. But don’t worry because we’re going to explain how the effects create their distinctive sound, describe what the various controls do and give you some tips on how to make the most of them in your music.
One of the great things about modulation effects is that they are quite simple for today’s computers to create. This means the plug-ins that create these effects don’t take up much processing power, so generally you can get away with using as many of them as you like, even on slower computers.
Vibrato Effects such as chorus, phasing and flanging are called modulation effects because they are created by using a process known as pitch modulation. To create this pitch modulation, a low frequency oscillator (LFO) is used. An LFO is like the oscillators used in synthesisers to create sound, except with an LFO the frequencies are so low that they can’t be heard by human ears.
However, an LFO is useful because it can be used to influence other elements of a sound. In the case of pitch modulation, the sound is first delayed by a few milliseconds and then the LFO is used to modulate this delay time.
