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make music now Modulation FX masterclass

048 | COMPUTER MUSIC FEBRUARY 2006 TUTOR IAL

ModulationDiscover what modulation’s all about and how you can

incorporate its family of effects into your tracks

This month in our Advanced FX

series we’re looking at the class

of processing tools and

techniques known as modulation

effects. This is a bit of a strange one, as

unlike reverb and delay effects (all the

respective types of which are merely

variations on a theme), modulation

effects are connected in the sense that

they all share a common element –

namely, they involve some type of

modulation. In other ways, many

modulation effects can be quite

different. So what’s it all about?

Well, modulation, in production

terms, simply means using one

parameter to control another. In

practice, with effects, this almost always

involves using a Low Frequency

Oscillator to exercise said control,

although there are some exceptions.

But never mind that for now: if

‘modulation effects’ is simply an

umbrella term for a variety of different

effect types, we’d better have a go at

explaining the main ones… cm

On the DVDTUTORIAL FILES

The audio files used in the walkthrough on p51 can be found in the Tutorial Files folder on the DVD

Modulation typesCHORUS

Legend has it that chorus was inventedby Roland in their Jazz Chorus amplifier.

The amp sent a dry signal to one ampand speaker, and the same signal wasdelayed, modulated and sent to another amplifier and speaker within the samecabinet. This is a good explanation of how chorus works – except that insteadof feeding two amps, in a modern plug-in

the two signals are combined. Thesecond, modulated signal is not only delayed but also pitchshifted slightly, andan LFO controls the modulation of thispitch and thus the character of theeffect. Originally intended to simulate

the sound of more than one instrumentor vocal part, it soon became apparent

that it didn’t, andnow chorus issimply used as acreative effect.

7 Chorus sounds

particularly good on

pads and guitar riffs

PHASING AND FLANGING

The terms phasing and flanging havebecome confusing over the years, largely because the effect we now call flanging

was originally called phasing and theeffect we now call phasing is rather similar to flanging. The concept of

flanging stems from running two synced tape machines (playing the same signal)and manually slowing one with your

finger (and then the other). This created adistinctive whooshing sound. Phasing, on

the other hand, is similar, but without the fast changes and whooshes. In bothcases, as the two signals move closer (phasing) and further (flanging) apart,some interesting frequency cancellationsoccur as similar or identical frequenciescancel each other out or build on eachother. Dynamic variation to these effectscan be produced with an LFO controlling

the timing and intensity of themodulation, and in the case of flanging,

the effect is intensified by feeding someof the wet signal back into the equation.

RING MODULATION

Ring modulators are tricky to understand,but very simple to use, fortunately. Thebasic concept is that two signals arebrought together and then the sum anddifference of the frequencies of both aregenerated, while the rest of the signal isremoved. So if you had a 500Hz sine

wave and an 800Hz sine wave, theoutput would feature tones at both1300Hz and 300Hz. Of course, realsounds are much more complicated

than that, and it would make your head explode to figureout on paper what thisactually produces when twocomplex signals arecombined. To summarise theeffect, it can sound an awfullot like the Daleks talking.

VIBRATO/TREMOLO/PANNER

If you reduce the delay time inmodulation effects down to 10ms or less,it's difficult to distinguish between theoriginal and delayed signal, and so youcan then get on with the business of creating tremolo and vibrato. Variationson a theme, the basic difference is that

the latter involves modulating the pitch of a sound, the former the volume. Thingsget a bit more interesting when you offset

the left and right channels of a tremoloso that as one peaks the other’s at itslowest point, thusgenerating either synced or LFO-driven panning, theuse of whichshould be self-explanatory!

7 Tremolo is an

endlessly useful

volume-related effect

ADVANCEDEFFECTS

PART 4

CMU96.t_fx 048CMU96.t_fx 048 22/12/05 11:24:27 am22/12/05 11:24:27 am



TUTOR IAL FEBRUARY 2006 COMPUTER MUSIC | 049

Q&A focus

make music nowModulation FX masterclass

THE ANATOMY OF MODULATION EFFECTS

Discover the inner workings of some popular modulation effects. The onesshown are from Cubase, but your software will probably have equivalents…

Chorus

Flanger

Ring modulator

FREQUENCY This sets the speed of themodulation effect

SHAPE

Enables you to choose themodulating waveform type

DELAY

Sets the delay time of the repetition(s)

STAGES This adds additional ‘voices’(up to three more), for anultra-thick sound

MIXControls the balance between the wet and dry signals

TEMPO SYNC

Does what it says on the very handy tin

RATEIn sync mode, this determines the note value for

the modulation; otherwise you can set it freely

DEPTH

Sets the depth of themodulation sweeps

STEREO BASISOffers a choice between mono, normaland enhanced stereo operation

FEEDBACKGreater feedback settings producea distinctive metallic effect

OSCILLATOR RANGESets the oscillator’s

frequency range

OSCILLATOR LFO AMOUNT

Controls the effect of the LFO on the oscillator frequency

OSCILLATOR ENVELOPE AMOUNTControls the effect of the envelope(generated by the incoming signal) on theoscillator frequency

OSCILLATOR WAVEDetermines the oscillator wave

type (square, sine, etc)

OSCILLATOR FREQUENCYControls the oscillator frequency tobetween plus or minus two octaves,

within the selected range

ROLL-OFF A low pass filter for smoothing the oscillator waveform

INVERT STEREOInverts the LFO for the right-handchannel, creating a stereo effect




050 | COMPUTER MUSIC FEBRUARY 2006 TUTOR IAL

make music now Modulation FX masterclass

MODULATION EFFECTS WILL almost

always take away from the sense of

presence of a sound at the same time

as they give it size and space, so be

careful what you use them on. Used on

lead elements they’ll detract from

energy and prominence in most mixes.

TO COUNTER THE tendency of chorus

to push sounds into the background, try

applying it only to the reverb send signal

– or insert it into the reverb bus itself.

This gives some lush thickness to the

sound, but will allow you to keep the

main sound upfront.

IF YOUR PHASER or flanger enables

you to sync its modulation action to

track tempo, be sure to do so, as you

can set up some nice cyclic patterns

(over eight bars, for example), which

make the effect much more useable

and easy to manage when mixing

your track.

The thing about modulation effects

is that they have almost no

parallels in nature. In fact, the

closest approximation to flanging in the

real world is a low-flying jet aeroplane

skimming a concrete jungle (so much

so that almost every single explanation

of flanging you’ll ever read uses this

example), and that’s about as close to

natural as any of these effects really

come! Consequently, they fall into the

category of effects that we like to call

‘special’. Why? Because, with a very few

exceptions, any time you use them they

will be very apparent and are nearly

always meant to be noticed (there are

very few reasons you might add them to

impart realism and subtlety). As with any

such effect, they can become tiresome

very quickly, so restraint is the name of

the game. We wouldn’t recommend you

try all of the forthcoming suggestions

and techniques in one track, but don’t

let that put you off trying them all at

some point and coming up with some

of your own. With that in mind, we’ve

put together a selection of tips to get

you thinking about some creative (or

useful) applications for these potentially

extreme effects…

Special effects

TRY PLAYING WITH the modulation

rate on your phaser. Slow speeds create

nice long sweeps, while much faster

speeds can have a great old-school

rotary cabinet effect. You can even

alternate between the two, or have one

panned left and the other right…

IF YOU’RE AFTER a classic ensemble

effect, take a leaf from the synth

programmer’s book and use a

pitchshifter in detune mode to generate

another version of your signal, slightly

detuned from the original. This avoids

the distinctive cycling of the LFO.

THE SOUND OF the electric guitar is,

quite simply, the sound of the effects

being used on it, and some of the most

enduringly popular are chorus, phasing

and flanging. So if you’re ever working

with an electric guitar riff, you’d be crazy

not to at least try one or all of them.

MODULATION EFFECTS ALL rely on a

very critical wet/dry balance, so it’s

generally more convenient to use them

as insert effects rather than as part of a

send and receive effects loop. They

should also usually come near the end

of an effects chain (ideally, penultimate).

A GREAT WAY to get more useable and

musical results from the unpredictable

and usually severe sounding ring

modulator is to mix in some (or loads!)

of the unprocessed main signal. Taken

to the opposite extreme, the ring

modulator output can be used as

nothing more than a backing layer.

PERCUSSION LOOPS AND individual

drum hits can sound fantastic when run

through ring modulators. Try combining

snares, hats and cymbals for some very

electronic and bizarre techno

percussion sounds…

Modulation tips

Use them on… There are no hard and fast rules as to what you can and can’t use modulation effects on, buthere are some suggestions based on the most popular uses.

CHORUS

Backing vocals, pads, backingguitars, strings

VIBRATO, TREMOLO

Pads, vocals,percussion, loops

RING MODULATION

Special vocal effects, drumloops, edits

PHASING AND FLANGING

Guitars, lead synths, drumloops, edits

1Some chorus effects offer multiple delays for an

even thicker sound

3If your modulation

effects offer tempo

sync, use it!

3 Try a straight

pitchshifter to avoid

obvious LFO cycling




TUTORI AL FEBRUARY 2006 COMPUTER MUSIC | 051

Q&A focus

make music nowModulation FX masterclass

MOST MODULATION EFFECTS

(particularly phasers) will create

significant fluctuations in the signal levelof any channel to which they’re applied.

To counter this, add a compressor

immediately after the inserted

modulation effect, thus flattening the

level slightly.

RING MODULATION EFFECTS

REQUIRE simultaneous signals to

generate any noise whatsoever, so if

your ring modulator accepts two

external signals you might want to add

a compressor to each, just to be sure of constant sound output.

PHASING CAN BE just the ticket for

taking the edge off harsh sounds and

frequencies. Try some subtle phasing on

your lead synths and guitars – it can

soften them up and help them fit into a

mix. It’s also great for softening

distortion effects.

FOR CLASSIC CHORUS, flanging and

phasing effects, the best initial wet/dry

balance is 50/50. Using this as your

starting point, try shifting the balance,

and you’ll find that you usually end up

back on the halfway line…

SOME PHASERS ENABLE you to set a

frequency floor and ceiling, above and

below which the phasing of frequencies

is disabled. If yours does, try narrowing

the range to around 300Hz-5KHz, as

this will offer the greatest audible effect without significant volume fluctuation.

ALMOST ANY MODULATION plug-in

can be used as a stereo width effect,

simply by offsetting the modulation of

the left and right channels. As one peak

is reached, the other side is in the

trough – just as with tremolo.

DON’T FORGET TO automate your

controls. By their nature, modulation

effects are very in-your-face, so listenerscan get tired of them pretty quickly. Turn

this to your advantage and only use

them at certain times – or at least

lessen their effect in parts.

IF YOUR FLANGING is more like a

windy fart than an Airbus test-flight, try

whacking the feedback up nice and

high – this will intensify the whooshing

effect that we all know and love (blame

Van Halen for that one… )

IF YOUR PHASER enables you to set

the delay time manually, you can use

this to shape the sound. Shorter delay

times make for more high frequency

action and a thinner sound. Lengthen them and the sound is fatter and more

focused on the lower frequencies.

YOU CAN USE chorus and other

modulation effects to generate some

fantastic stereo effects by panning the

dry signal to one side and the

effected signal to the other side. The

resulting effect can be used to give

width to a sound, to help it blend into a

mix, or to add dynamic excitement. To

find out how, follow the walkthrough on the right… cm

“IF YOUR FLANGING IS MORE LIKE A

WINDY FART THAN AN AIRBUS TEST

FLIGHT, WHACK UP THE FEEDBACK”

STEP BY STEP Using chorusto create stereo width

3Finally, insert the chorus plug-in of your choice into the auxiliary channel (if it has a wet/dry control, set it to fully wet). You may

need to tweak the left and right balance again. Also, if the effect

is too obvious, try some less extreme panning.

2Now pan the audio channel completely left, send the output to

the auxiliary channel and pan the auxiliary channel all the way to

the right. Balance the levels of the left and right channels now,using the send control on the original channel and the volume on

the auxiliary. >>

1Start by creating one audio channel and one auxiliary channel in

your sequencer. Set the tempo to 128bpm, add the audio fileSynth Riff @ 128bpm (on the DVD) to the audio channel and set

the project to loop over two bars. >>

1Live’s phaser puts all the controls you need in

one very clear interface

1For some serious flanging action, make sure you

experiment with the feedback control

1 When it comes to bundled plug-ins, Logic leads

the pack, and its Phaser is quite excellent


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