Nowthatwe’vemadea coupleof
customwavetablesofourown,let’s
seehowFathomCMallowsusto
manipulatethem.Youmaywellbe
wonderingaboutoursecondwavetable.
Thatonecanbecombinedwiththefirstin
interestingways,theamountofwhichis
controlledbytheAmountknob.Setit to
thehalfwayposition.1
Thatmadelittledifference,asour
AlgorithmknobissettoSubtract.
Thisknobcontrolshowthetwo
wavetablesinteractwithoneanotherto
createa compositewavetable.Let’stry
settingit toMorphinstead.Now,whenwe
twisttheAmountknob,thesound
morphsbetweenthetwowavetables,
creatingsomethingnewinbetween.2
Next,notethe Frequency parameter.
Thisisn’tan overall pitch knob, but
ratheraffectsthe right-most wavetable
which,incidentally, is referred to as the
‘operator’,while the leftmost table is
calledthe‘operand’. Changing the
operatorfrequency can drastically affect
thesound,especially when the Algorithm
issettoPhase, as we have here.3
> Stepbystep
5.Buildinga two-oscillatorwavetablevoiceFathomCM’sabilitytogenerateand
combinewavetablesisverypowerful,
butasmentionedearlier,wavetablesonly
springtolifewhenmodulated.This
modulation-drivenscanning– anda
classicanaloguesignalpath– earnedthe
PPGWaveitslegendarystatus.Westart
whereweleftoffinourprevioustutorial,
butreturntheFrequencyknobto1.0.1
Next,wesetouroperatorwavetable’s
Indexbacktoitsfirstposition.That’s
therightmostIndexknob.Oursoundis
quiteabrupt,soclicktheOscillator
buttononthelefttogettoourfamiliar
Oscillatorcontrols.WereducetheVolume
to 0 , andclickitscentretoselectit asa
modulationtarget,thenAddMod,
choosinganADSRasitssource.2
Wecrankthe amount of modulation to
full,thenadjust the envelope to create
a lessstaticoverall amplitude. We
decreasetheattack level on ours, and
increasedtherelease time. We also give
thePeriodknob a little nudge to expand
thewholething. Our sound now rings out
a bitfora bell-like tone.3
Now,weclickSignalFlow, chooseour
WaveTablecomponent(theonlyone
yetinplay)andthengobacktoour
parameterseditor.WiththeAmountknob
setto 0 , weclickitscentretomakeit a
modulationtarget,AddMod, thenchoose
anotherADSRasthemodulator.Setthe
modulationamounttoaround0.70.4
Thecompositewavetablenowshifts
fromouroperandtoouroperatorina
verydramaticfashion– it’sa bittoo
dramatic,tobehonest!Let’saddanother
segmenttoourenvelopeanddrawa more
interestingshape.Onceagain,weincrease
thePeriod, thistimetoover 11. Whenwe
playandholda note,wegeta slowly
shiftingtimbre.5
We’venowgot a lovely chiming timbre
withsomereal interest in the sustain
segmentofthe sound. Let’s add another
elementofinterest by assigning a Note
Velocitymodulator to affect the amount
ofourmostrecent envelope modulator.6
> Stepbystep
6.Buildinga classicwavetablesynthvoice66 / COMPUTER MUSIC / July 2019
make music now / digital modular synthesis with fathom cm