o . . . . . . _ . . _____ _____ _ __| |_ ___ _ __ ___ ___ / _ \ \ / / _ \ '__| __/ _ \| '_ \ / _ \/ __| o . | (_) \ V / __/ | | || (_) | | | | __/\__ \ \___/ \_/ \___|_| \__\___/|_| |_|\___||___/ . o . . . o _ _ _ _ . . (_)_ __ ___ _ _ _ __ | |_| |__ ___ ___(_)___ | | '_ \ / __| | | | '_ \| __| '_ \ / _ \/ __| / __| . | | | | | \__ \ |_| | | | | |_| | | | __/\__ \ \__ \ . |_|_| |_| |___/\__, |_| |_|\__|_| |_|\___||___/_|___/ |___/ . o . o . . . o o o o . . _____ /\ o | | . |\ | | / \ | | | \ | || | ___/ \ ____ __| | ___ ___| \____ _|||||||||__ \ / | | | || | \/ |___| | | . o o o . . o o o . . . . . Synth sounds can sound very sterile sometimes, especially if you only have 1 waveform - one oscillator - a static cold flat wave. Of course, you can add some vibrato with an LFO on the pitch to make it less sterile and more alive. But you can also add soft 'overtone harmonics' to make it sound more 'organic' and less harsh. An important factor in real instruments, and what gives them their character, is how certain harmonics resonate in and outside the instrument. For example: When you hit a note on a piano you don't just hear the pure pitch of the note you just played. Inside, certain other strings apart from the one you just hit also vibrate, a lot softer in volume, almost unnoticeable.... but enough to give a certain harmonic content and character to the sound. Nature has its way and these harmonic frequencies always follow the same path, we won't go in too much scientific blablah here now if you want to know more about that look it up in google. So the frequencies that give these harmonics, which are always pretty much the same, are called overtones or partials. And these are the notes/frequencies of these overtones: C - C(1 octave up) - G - C(2 octaves up) - E - G With these notes in mind its easy to create 'natural' sounding overtones on a synthesizer. EXAMPLE: Let's say we have 5 oscillator synth, a modular system of some sorts. and we want to add some overtone harmonics: ________________ ______________ | whatever | | | | osc 1 you want |______________ volume 100% __________| filter | |________________| | env etc. |_______ _________________ |______________| | | pitch | | | osc 2 sine +12 |_____________ volume 20% __________ | |_________________| \ ______________ | _________________ \ | || | pitch | \ | filter. || | osc 3 sine +19 |_____________ volume 10%______________\____| env etc || |_________________| / _/ |______________|| _________________ / | | | | pitch | / | |________| | osc 4 sine +24 |_____________ volume 5% ___________/ | | |_________________| | | _________________ / mixer | pitch |_____________ volume 2% _____________/ maybe other | osc 5 sine +28 | filter vca |_________________| env etc. | | \ / V output Oscillator 1 is the main fundamental frequency tone - tuned neutral on C Oscillator 2 Tune 1 octave up (+12 ) volume 20% Oscillator 3 Tune 1 octave + 7 notes up (+19) volume 10% Oscillator 4 Tune 2 Octaves up (+24) volume 5% Oscillator 5 Tune 2 Octaves + 4 notes up (+28) volume 2% (If you have more oscillators you can tune oscillator 6 to 2 Octaves + 7 notes up (+31) volumet 1% etc.etc.etc. Of course you don't have to follow the laws of nature, try any different frequency and see what eerie vibes you can give to your sounds - from a universal parallel dimension were our laws of physics do not comply. If you have a more common 3 oscillator synth like a minimmoog, novation nova, Waldorf Blofeld etc. you can add only 2 more overtone notes - either G, C, E...experiment see what gives the best result. Some stuff to check: Give different volumes to different oscs..use keytracking, randomize the volume etc. It should be barely noticeable, slightly within the human hearing range. Let the volume of each oscillator gradually go down, the lower ones louder, the higher ones softer. If possible give each oscillator or at least the overtone ones its own VCA envelope, higher pitches overtones have shorter sustain/release then the lower ones. Try different waveforms, maybe even for the different partial oscillators: A sinewave might be more suited to the high overtones, a soft square to the low- but it can also be the other way around. To finish it off add an almost unnoticeable amount of noise to blend everything together in a nice organic soup. If you have a pitchshifter that can do more then 1 tone at the same time (Harmonic pitchshifter or whatever these things are called) - you can set the pitches to the overtone series and put the dry/wet mix really low so you can barely hear it but it does effect the sound. ___ / / By Prof.Dr.Emiel EmmerEend University of Texel. / / \_/