[{"data":1,"prerenderedAt":699},["ShallowReactive",2],{"page:\u002Flearn\u002Foscillators":3},{"id":4,"title":5,"article":6,"body":7,"description":691,"extension":692,"meta":693,"navigation":6,"path":694,"seo":695,"seoTitle":696,"stem":697,"__hash__":698},"pages\u002Flearn\u002Foscillators.md","Oscillators: where every sound starts",true,{"type":8,"value":9,"toc":680},"minimark",[10,14,23,35,46,51,62,70,109,132,136,139,154,157,236,293,306,310,318,356,371,417,421,432,444,447,465,500,504,518,521,578,582,585,610,621,644,648],[11,12,5],"h1",{"id":13},"oscillators-where-every-sound-starts",[15,16,17,18,22],"p",{},"Every patch begins with something that makes a sound, and almost always that's an ",[19,20,21],"strong",{},"oscillator",". It's the simplest module in the rack, and it holds most of the ideas the rest of synthesis builds on. By the end of this guide you'll know why a note has a pitch, why some waves sound bright and others soft, and why synth players stack two oscillators slightly out of tune.",[15,24,25,28,29,34],{},[19,26,27],{},"New to patching?"," Take the ",[30,31,33],"a",{"href":32},"\u002Fplay?build","5-minute guided build"," first. It walks you through adding modules, patching cables, and unplugging and rerouting them, which every Try it box here assumes you can do.",[15,36,37,38,41,42,45],{},"Each ",[19,39,40],{},"Try it"," box opens the synth with its steps pinned on the rack, so you can read and listen at the same time. When you are done, ",[19,43,44],{},"Back to the guide"," (or your browser’s Back button) brings you back to the same spot.",[47,48,50],"h2",{"id":49},"a-sound-is-something-wobbling","A sound is something wobbling",[15,52,53,54,57,58,61],{},"When your speaker plays a sound, its cone pushes the air forwards and backwards. If that push repeats at a steady rate, your ear hears a ",[19,55,56],{},"pitch",". Repeat it 110 times a second and you hear a low A. Repeat it 440 times a second and you hear the A a tuning fork plays. That rate is the ",[19,59,60],{},"frequency",", measured in hertz (Hz): repeats per second.",[15,63,64,65,69],{},"An oscillator is just a thing that repeats a shape, over and over, forever. That's the whole job. In Kables the classic one is the ",[30,66,68],{"href":67},"\u002Fmodules\u002Fvco","VCO",", short for voltage-controlled oscillator.",[71,72,75,106],"try-it",{"title":73,"add":74},"Your first oscillator","vco",[76,77,78,95],"ol",{},[79,80,81,82,85,86,89,90],"li",{},"Drag from the VCO's ",[19,83,84],{},"OUT"," jack to the Output's ",[19,87,88],{},"MONO"," jack. You'll hear a steady tone. ",[91,92],"wire",{"from":93,"to":94},"vco.out","out.in",[79,96,97,98,101,102],{},"Turn ",[19,99,100],{},"Tune"," slowly. Faster repeats, higher pitch. ",[103,104],"turn",{"module":74,"param":105},"freq",[15,107,108],{},"Now take your hands off and wait. Notice it never stops?",[15,110,111,112,116,117,121,122,126,127,131],{},"That last part surprises everyone. An oscillator doesn't play ",[113,114,115],"em",{},"notes","; it just runs. Deciding when a sound starts and stops is a separate job, done by a ",[30,118,120],{"href":119},"\u002Fmodules\u002Fvca","VCA"," and an ",[30,123,125],{"href":124},"\u002Fmodules\u002Fadsr","envelope",". That split is the heart of modular: each module does one thing, and you decide how they work together. They get ",[30,128,130],{"href":129},"\u002Flearn\u002Fenvelopes-and-vcas","their own guide",", next.",[47,133,135],{"id":134},"the-shape-is-the-colour","The shape is the colour",[15,137,138],{},"Play two oscillators at exactly the same pitch, one making a smooth curve and one making a jagged ramp, and they sound completely different. Why, if the pitch is the same?",[15,140,141,142,145,146,149,150,153],{},"Because any repeating shape is secretly a stack of simpler waves. There's the main one, at the pitch you hear (the ",[19,143,144],{},"fundamental","), plus quieter ones at 2×, 3×, 4× that frequency and so on, called ",[19,147,148],{},"harmonics",". You don't hear them as separate notes; you hear them as the ",[113,151,152],{},"colour"," of the sound. The shape of the wave decides which harmonics are there and how loud they are.",[15,155,156],{},"The VCO has the four classic shapes:",[158,159,160,176],"table",{},[161,162,163],"thead",{},[164,165,166,170,173],"tr",{},[167,168,169],"th",{},"Wave",[167,171,172],{},"What's in it",[167,174,175],{},"What it sounds like",[177,178,179,194,208,222],"tbody",{},[164,180,181,188,191],{},[182,183,184,187],"td",{},[19,185,186],{},"SIN","e",[182,189,190],{},"Only the fundamental. Nothing else.",[182,192,193],{},"Pure and soft, like a whistle or a flute. Great for deep sub-bass.",[164,195,196,202,205],{},[182,197,198,201],{},[19,199,200],{},"TRI","angle",[182,203,204],{},"A few odd harmonics, fading fast.",[182,206,207],{},"Still gentle, a little more present. Like a recorder.",[164,209,210,216,219],{},[182,211,212,215],{},[19,213,214],{},"SQR"," (square)",[182,217,218],{},"Only odd harmonics, fairly strong.",[182,220,221],{},"Hollow and woody, like a clarinet or an old video game.",[164,223,224,230,233],{},[182,225,226,229],{},[19,227,228],{},"SAW","tooth",[182,231,232],{},"Every harmonic.",[182,234,235],{},"Bright, buzzy, rich. The sound of strings, brass and most classic synth leads.",[71,237,239,286],{"title":238,"add":74},"Hear the colours",[76,240,241,252,263,270,277],{},[79,242,243,244,246,247,249,250],{},"Patch the VCO's ",[19,245,84],{}," into the Output's ",[19,248,88],{}," again. ",[91,251],{"from":93,"to":94},[79,253,254,255,257,258],{},"Click through the waves without touching the pitch: ",[19,256,186],{},", ",[259,260],"knob",{"module":74,"param":261,"is":262},"wave","sine",[79,264,265,257,267],{},[19,266,200],{},[259,268],{"module":74,"param":261,"is":269},"triangle",[79,271,272,257,274],{},[19,273,214],{},[259,275],{"module":74,"param":261,"is":276},"square",[79,278,279,280,282,283],{},"and back to ",[19,281,228],{},". ",[259,284],{"module":74,"param":261,"is":285},"sawtooth",[15,287,288,289,292],{},"Listen for how ",[113,290,291],{},"bright"," each one is. The sine sounds almost like nothing is there; the saw sounds like it's buzzing with detail. That buzz is all those harmonics.",[15,294,295,296,300,301,305],{},"This is why the sawtooth is everyone's favourite starting point. It has the most harmonics, so it gives a ",[30,297,299],{"href":298},"\u002Fmodules\u002Fvcf","filter"," the most to carve away. Start bright, then shape it darker. That's called subtractive synthesis, and it's how most classic synth sounds are made (more in the ",[30,302,304],{"href":303},"\u002Flearn\u002Ffilters","filters guide",").",[47,307,309],{"id":308},"see-the-shapes","See the shapes",[15,311,312,313,317],{},"Hearing the difference is one thing; seeing it makes it click. The ",[30,314,316],{"href":315},"\u002Fmodules\u002Fscope","Scope"," module draws whatever you patch into it, so you can watch a wave's shape while you listen to it.",[71,319,322,329],{"title":320,"lesson":321},"Look at sound","06-scope-seeing-sound",[15,323,324,325,328],{},"This patch has a sine at 220 Hz and a square at 330 Hz going into a scope. In ",[19,326,327],{},"Time"," mode you see each wave's shape. Compare the smooth sine with the square's sharp corners: those corners are where the extra harmonics live.",[330,331,332,344],"ul",{},[79,333,334,335,338,339],{},"Switch to ",[19,336,337],{},"X\u002FY",". Because 330 is exactly 1½ × 220, the two waves line up and draw a steady loop. ",[259,340],{"module":341,"param":342,"is":343},"scope","mode","xy",[79,345,346,347,350,351,355],{},"Now nudge VCO B's ",[19,348,349],{},"Fine"," knob. ",[103,352],{"module":353,"param":354},"vco#b","fine"," The figure starts to turn, because the two waves are slowly drifting out of step. Hold on to that idea for later.",[15,357,358,359,362,363,367,368,370],{},"The scope shows a wave over ",[113,360,361],{},"time",". To see the harmonics themselves, use the ",[30,364,366],{"href":365},"\u002Fmodules\u002Fspectrum","Spectrum"," module, which shows a sound over ",[113,369,60],{},": bass on the left, treble on the right.",[71,372,375,378],{"title":373,"lesson":374},"Count the harmonics","47-spectrum-and-tuner",[15,376,377],{},"Hold a key and switch the VCO between waves while you watch the Spectrum:",[330,379,380,387,394,405],{},[79,381,382,384,385],{},[19,383,186],{}," draws a single spike. One frequency, nothing else. ",[259,386],{"module":74,"param":261,"is":262},[79,388,389,391,392],{},[19,390,228],{}," draws a whole comb of spikes, one for every harmonic. ",[259,393],{"module":74,"param":261,"is":285},[79,395,396,398,399,402,403],{},[19,397,214],{}," draws every ",[113,400,401],{},"other"," spike: only the odd harmonics. ",[259,404],{"module":74,"param":261,"is":276},[79,406,407,408,411,412,414,415],{},"The second Spectrum is in ",[19,409,410],{},"TUNER"," mode. Turn the VCO's ",[19,413,349],{}," knob and watch it tell you how many cents out of tune you are. ",[103,416],{"module":74,"param":354},[47,418,420],{"id":419},"pitch-works-in-octaves","Pitch works in octaves",[15,422,423,424,427,428,431],{},"Here's something odd about ears: we don't hear pitch in hertz, we hear it in ",[113,425,426],{},"ratios",". Going from 110 Hz to 220 Hz sounds like the same step up as going from 440 Hz to 880 Hz, even though the second jump is four times as many hertz. Each doubling sounds like \"the same note, higher\": an ",[19,429,430],{},"octave",".",[15,433,434,435,439,440,443],{},"So modular synths control pitch per octave. The VCO's ",[30,436,438],{"href":437},"\u002Flearn\u002Fglossary#v-oct","V\u002FOCT"," input works like this: add ",[19,441,442],{},"1.0"," and the pitch goes up one octave (the frequency doubles). Add 1\u002F12 (about 0.083) and it goes up one semitone, the step between neighbouring keys on a piano. That's why a keyboard can play a VCO just by sending numbers down a cable.",[15,445,446],{},"The knobs follow the same idea:",[330,448,449,454,460],{},[79,450,451,453],{},[19,452,100],{}," sets the starting pitch. It defaults to middle C (261.6 Hz), so keyboards play in tune.",[79,455,456,459],{},[19,457,458],{},"Oct"," jumps by whole octaves.",[79,461,462,464],{},[19,463,349],{}," nudges by cents, hundredths of a semitone. Tiny, but it matters more than you'd think (next section).",[71,466,469,479],{"title":467,"lesson":468},"Play it","01-your-first-note",[15,470,471,472,474,475,478],{},"Here a Keyboard drives the VCO's pitch. Follow the blue cable from the Keyboard's ",[19,473,438],{}," output to the VCO: that cable carries ",[113,476,477],{},"which note",", as a number.",[76,480,481,491],{},[79,482,483,484,487,488],{},"Play with ",[19,485,486],{},"A S D F G H J K"," on your computer keyboard. ",[489,490],"play",{},[79,492,493,494,496,497],{},"Change the VCO's ",[19,495,458],{}," and every key moves by an octave, because the keyboard's number is added to the VCO's own setting. ",[103,498],{"module":74,"param":499},"oct",[47,501,503],{"id":502},"two-oscillators-are-bigger-than-one","Two oscillators are bigger than one",[15,505,506,507,509,510,513,514,517],{},"Remember the scope figure turning when you nudged ",[19,508,349],{},"? When two oscillators are ",[113,511,512],{},"almost"," the same pitch, their waves drift in and out of step. When they're in step they add up and get louder; when they're out of step they partly cancel. The result is a slow, shimmering swell called ",[19,515,516],{},"beating",", and it's the secret behind the classic \"fat\" synth sound.",[15,519,520],{},"A few cents of detune between two or three sawtooth oscillators is how big analog leads, pads and basses are made.",[71,522,525,528],{"title":523,"lesson":524},"Make it fat","05-mixer-fat-sounds",[15,526,527],{},"Three sawtooth VCOs are mixed together: two tuned 8 cents either side of the note, and a third an octave below.",[76,529,530,547,555,563],{},[79,531,532,533,537,538,543,544],{},"On the ",[30,534,536],{"href":535},"\u002Fmodules\u002Fmixer","Mixer",", turn levels 2 and 3 down to zero, leaving one VCO. Thin, isn't it? ",[259,539],{"module":540,"param":541,"below":542},"mixer","l2","0.05"," ",[259,545],{"module":540,"param":546,"below":542},"l3",[79,548,549,550,543,553],{},"Bring the others back in, and hear it widen. ",[259,551],{"module":540,"param":541,"above":552},"0.3",[259,554],{"module":540,"param":546,"above":552},[79,556,557,558,560,561],{},"Push one VCO's ",[19,559,349],{}," to ±25¢: now it's wobbly, almost seasick. Too much beating becomes a sound effect. ",[103,562],{"module":74,"param":354},[79,564,565,566,569,570,573,574],{},"Patch a VCO's ",[19,567,568],{},"SUB"," output into the mixer's free ",[19,571,572],{},"IN 4",". It's a square wave one octave below, adding weight underneath. ",[91,575],{"from":576,"to":577},"vco.sub","mixer.in4",[47,579,581],{"id":580},"beyond-the-four-shapes","Beyond the four shapes",[15,583,584],{},"Once the basics feel familiar, two modules take the idea further.",[15,586,587,588,592,593,596,597,600,601,605,606,305],{},"The ",[30,589,591],{"href":590},"\u002Fmodules\u002Fwto","Wavetable"," oscillator can ",[19,594,595],{},"morph"," smoothly between four shapes, and its ",[19,598,599],{},"Width"," control squeezes one half of the wave and stretches the other. Patch a slow ",[30,602,604],{"href":603},"\u002Fmodules\u002Flfo","LFO"," into either, and the shape changes while the note plays, so the sound evolves instead of sitting still (",[30,607,609],{"href":608},"\u002Fplay?lesson=17-wavetable-and-pwm","lesson 17",[15,611,612,616,617,305],{},[30,613,615],{"href":614},"\u002Fmodules\u002Fnoise","Noise"," is the opposite of an oscillator. It never repeats, so it has no pitch at all, just every frequency at once. That makes it perfect for things without a note: wind, surf, the hiss of a hi-hat (",[30,618,620],{"href":619},"\u002Fplay?lesson=11-noise-wind-and-hats","lesson 11",[15,622,623,624,628,629,633,634,638,639,643],{},"Some sources copy real objects instead of drawing waves. The ",[30,625,627],{"href":626},"\u002Fmodules\u002Fstring","Plucked String"," fires a puff of noise into a loop one pitch-period long, and it rings like a guitar string (",[30,630,632],{"href":631},"\u002Fplay?lesson=18-plucked-string","lesson 18","). The ",[30,635,637],{"href":636},"\u002Fmodules\u002Freso","Resonator"," rings at the oddly spaced frequencies of bells, bars and gongs when something strikes it (",[30,640,642],{"href":641},"\u002Fplay?lesson=22-resonator-bells-and-bars","lesson 22","). Different methods, same idea: something vibrates, and its pattern of harmonics is what you hear.",[47,645,647],{"id":646},"what-to-remember","What to remember",[330,649,650,658,664,670,673],{},[79,651,652,653,655,656,431],{},"An oscillator repeats a shape forever. How fast it repeats is the ",[19,654,56],{},"; the shape is the ",[19,657,152],{},[79,659,660,661,663],{},"Brighter waves have more ",[19,662,148],{},". Sine has none, saw has all of them, which is why saws are great to filter.",[79,665,666,667,431],{},"Pitch works in octaves: ",[19,668,669],{},"+1 on V\u002FOCT is one octave up",[79,671,672],{},"Oscillators never stop on their own. Making notes start and end is the next job, for an envelope and a VCA.",[79,674,675,676,679],{},"Two oscillators slightly out of tune ",[19,677,678],{},"beat"," against each other and sound bigger than either one alone.",{"title":681,"searchDepth":682,"depth":682,"links":683},"",2,[684,685,686,687,688,689,690],{"id":49,"depth":682,"text":50},{"id":134,"depth":682,"text":135},{"id":308,"depth":682,"text":309},{"id":419,"depth":682,"text":420},{"id":502,"depth":682,"text":503},{"id":580,"depth":682,"text":581},{"id":646,"depth":682,"text":647},"A friendly guide to oscillators for modular synth beginners. Why a sound has a pitch, why a sawtooth sounds brighter than a sine, how V\u002FOCT works, and why two slightly out-of-tune oscillators sound so big.","md",{},"\u002Flearn\u002Foscillators",{"title":5,"description":691},"How oscillators and waveforms work — sine, triangle, saw and square explained","learn\u002Foscillators","8vmxJA2ME3JEDztbxVXah2-23gGcNQCH9r8W55_Binc",1792599837966]