Detailed Program Editing Using Filters
49
Using Filters
Thefiltersallowsyoutodiminishoremphasize
specifiedfrequencyareasofthesound.
Thetoneofthesoundwilldependsignificantlyonthe
filtersettings.
Thebasicfiltersettings,includingtherouting,type,
cutofffrequency,andresonance,aresetontheP3:
Filterpage.
Filter Routing
Eachoscillatorhastwofilters,FilterAandFilterB.The
Routingparametercontrolswhetheroneorbothofthe
filtersareused,andifbothareused,itcontrolshow
theyareconnectedtoeachother.
TheSingleroutingusesonlyFilterAasasingle2‐pole,
12dB/octavefilter(6dBfo
rBandPa
ssandBandReject).
TheSerialroutingusesbothFilterAandFilterB.The
oscillatorfirstgoesthroughFilterA,andthenthe
outputofFilterAisprocessedthroughFilterB.
ParallelalsousesbothFilterAandFilterB.The
oscillatorfeedsbothfiltersdirectly,andtheoutput
sof
thetwofiltersarethensummedtogether.
The24dB/4‐poleroutingmergesbothfilterstocreatea
single4‐pole,24dB/octavefilter(12dBforBandPass
andBandReject).IncomparisontoSingle,thisoption
producesasharperroll‐offbeyondthecutoff
frequency,aswellasas
lightlymoredelicate
resonance.Manyclassicanalogsynthsusedthis
generaltypeoffilter.
SerialandParallelRouting
Filter Types
Thisselectsthepartsofthesoundwhichwillbe
affectedbythefilter,asdescribedbelow.Withthe
SerialandParallelroutings,youcanindependentlyset
thetypesforFilterAandFilterB.
Thefilterswillproduceverydifferentresults
dependingontheselectedfiltertype.Theselections
willchangesli
ghtlyacco
rdingtotheselectedFilter
Routing,toshowthecorrectcutoffslopeindBper
octave.
LowPass.Thiscutsoutthepartsofthesoundwhich
arehigherthanthecutofffrequency.LowPassisthe
mostcommontypeoffilter,andisusedtomakebright
timbressou
nddarker.
HighPass.Thiscutsoutthepartsofthesoundwhich
arelowerthanthecutofffrequency.Youcanusethisto
maketimbressoundthinnerormorebuzzy.
BandPass.Thiscutsoutallpartsofthesound,both
highsandlows,exceptfortheregionaroundthecu
toff
frequency.Sincethisfiltercutsoutbothhighandlow
frequencies,itseffectcanchangedramatically
dependingonthecutoffsettingandtheoscillator’s
multisample.
Withlowresonancesettings,youcanusetheBand
Passfiltertocreatetelephoneorvintagephonograph
sounds.Withhigherresonancesettings,itcancreate
buzzyornasaltimbres.
BandReject
.Thisfiltertype–alsocalledanotchfilter–
cutsonlythepartsofthesounddirectlyaroundthe
cutofffrequency.Trymodulatingthecutoffwithan
LFOtocreatephaser‐likeeffects.
Filter A (Low Pass)Oscillator Filter B (High Pass)
Oscillator
Filter A (Low Pass)
Filter B (High Pass)