Modulation and filter effects

Chorus

delays a copy of the original signal, playing the delayed version alongside the clean signal

giving the effect of more than one instrument playing a signal

Origins of chorus

made one voice or instrument sound like a chorus of voices/instruments

what the LFO in chorus does

delays a signal by a small varying amount of time, which affects the pitch simulating the sound when a number of musicians play together

like adding a vibrato to wet signal

Modulated delay effects

periodic modulation of delay time; an LFO is used to control how much the wet signal is delayed by

Parameters of modulation

• Rate- Speed at which modulation takes place

• Depth- the greater the depth the wider the range of values for the delay time

• Feedback- percentage of output from effect put back into input

Flanger

‘swirling’, ‘wooshing’ or ‘jet plane effect’

effect fed back in using the feedback control creating a sweeping pitched sound

Comb filtering

slight delayed version of a signal combines with the direct sound causing destructive interference

can create thin sound, can be used as creative effect

Famous song which uses flanger

seal - bring it on (1994)

Phaser

Similar effect to flanger but it is generally subtler

effect is created as the two signals combine in varying ways

a filter with an LFO sweeping through the frequency range

example of phaser

Eruption - Van Halen (1976)

tremolo

modulates volume of the signal using an LFO

song example of tremolo

Nancy Sinatra - Bang Bang (He Shot Me Down) (1966) electric guitar

Wah Wah

Makes instruments sound like they are ‘WAHing’ mainly used on guitars in funk music

created by sweeping the centre frequency of a band pass filter

Famous song which uses wah wah

Voodoo Child - Jimmy Hendrix (1968)

how modulation could be produced on tape recorders

simultaneously playing the recording on two tape machines

pressing down on one reel to slow it down slightly delaying and varying the pitch of the recording

combining the two signals creates a flange-like effect

Leslie Cabinet/rotary speaker

rotating horn

shifts pitch and changes volume and tone as the speaker spins

Ring modulation

creates a dissonant ringing effect

e.g. phrase ‘I am Iron Man’ in Black Sabbath - Iron Man (1970)