Making Music
  Computer Music Software and Hardware

Phasing

Phasing is very similar to flanging and not many people can listen to an effect and say whether it's one or the other so full marks to you if you can. Rumour has it that phasing was the first attempt to create the flanging sound electronically, but there's no need to get hung up on the history. In essence, phasing uses a narrow bandwidth filter. The source signal is split in two, one half is passed through the filter, phase shifting is introduced around the central frequency then it's mixed back with the original. This produces phase cancellations in the output and the whooshing sound is created by moving the filter up and down the frequency spectrum. Voila!

Phasing and flanging played a major part in many records during the late 60s and 70s. The one everyone remembers - even if they weren't around at the time - is the Small Faces' Itchycoo Park.

Phasing and flanging are excellent effects for adding interest to a sound. They are not as heavy as a filter sweep and can be applied to delicate sounds such as strings and vocals as well as to heavy guitar and synth sounds.

Ring-a-ding

Although these are the most common and popular modulation effects, there are many others. They include ring modulation, for example, which is traditionally a synthesiser effect but models have been developed to work with audio. Ring modulation takes two inputs and creates an output that is the sum of and difference between the frequencies of the two signals. Because of the mathematical way the signals are combined, the output frequencies are rarely part of the harmonic series and the result often sounds metallic. Steinberg's Ringmodulator in Cubase and Cubase SX has a built-in oscillator that is multiplied with the input signals to create a ring modulation effect.

Another effect usually found in the modulation category is the rotary speaker, based upon the Leslie speaker cabinet which was ubiquitously used with Hammond organs which were an essential, if heavy, part of every rock band in the 60s and 70s.

The original Leslie used rotating speakers to create a complex doppler effect that has become one of the most distinctive sounds in popular music. The doppler effect occurs when a sound moves towards and then away from the listener making the pitch rise and fall. Rotary speakers create a swirling chorus-like effect. Obviously, it's de rigour to use with a Hammond organ sound but you can run any instrument through it and at gentle levels it can be used for subtle effects with vocals and other light sounds.

Modulation, in its many forms, is now an essential part of modern music and can be used to enhance, thicken and enliven just about any sound from synthesised and acoustic sounds to vocals.

For more info... Vibrato vs tremolo: www.vibroworld.com/magnatone/vibrato.html Time-varying delay effects: http://ccrma-www.stanford.edu/~jos/waveguide/Time_Varying_Delay_Effects.html Harmonic series: www.sfu.ca/sonic-studio/handbook/Harmonic_Series.html www.redshift.com/~dcanright/harmser/ Phase cancellation: www.sfu.ca/sca/Manuals/ZAAPf/p/phase.html Leslie speakers: www.mitatechs.com/leslierumors.html