Harmonic distortion with the Soundtoys Decapitator

Harmonic distortion is the soul of electric music. But what is it? How do we make it? And what does it sound like on a simple source like a sine wave, and then applied to an electric guitar?

Automated transcript

Let's have some fun with harmonic distortion what is distortion and what's this harmonic thingy what's it today you're going to find out learn audio online with audio masterclass audiomasterclass.com let's start with a totally clean sine wave of 100 hertz that's all you'll hear 100 hertz with no other frequency components you'll need to be on speakers or headphones that can handle 100hz if you're listening on laptop speakers you probably won't hear much

why did i choose 100 hertz well it leaves plenty of room in the upper frequencies for harmonics and that's what i'm interested in today it would be nice to visualize this so i'll play the 100hz sine wave through an oscilloscope

plugin

we can see the frequency components more clearly using a spectrograph there will be only one at 100 hertz

the spreading out at the bottom of the spectrogram plot is so my mathematical friend tells me due to spectral leakage and you can either ignore it or look it up online let's just ignore it for now so now i'm going to create some distortion one way to do this is to insert a harmonic enhancement plugin i'm going to use the sound toys decapitator i'll start with the default settings

we can also look at this in the oscilloscope

there isn't much to see here but if we look at the spectrogram

now we can see that there's a strong component at 100 hertz which we expect and also components at 200 hertz and 300 hertz so the plug-in has created additional frequencies that were not originally present 200 hertz and 300 hertz a whole number multiples of the original 100 hertz frequency this is usual in string and wind musical instruments and also the human voice we call it the harmonic series in this case 100 hertz is the fundamental and also the first harmonic 200 hertz and 300 hertz are the second and third harmonics respectively because of the similar pattern of frequencies to the harmonic series we call this type of distortion harmonic distortion right now the distortion is fairly mild but i can easily increase it using the drive control of the decapitator

let's look at it in the oscilloscope

and the spectrogram

we can see changes in the waveform clearly the tops and bottoms of the waveform have been squared off the tilt is due to the low cut filter which is set to 20 hertz also the positive going and negative going halves of the waveform are slightly asymmetric every change from the shape of the sine wave contributes to the sound texture in the spectrogram we now see a mass of harmonics all at whole number multiples of the original 100 hertz fundamental some are missing and i'll attribute this to quirks in the decapitator plugin all of this is interesting but how does it apply to a real world instrument well here's an electric guitar

ish

it's a software instrument guitar and it sounds really quite weak like a real electric guitar direct from the jack but if i add the same distortion as i did to the sine wave it sounds like this

and with a little echo and reverb and maybe just a touch of mod will while i

play

at this point it sounds perfectly usable musically and would improve further with tweaking of the controls and of course this is just one distortion plugin and one setting there's an almost infinite variety of distortion effects and settings from which to choose the tune by the way is from caroline by sky i'll put a couple of links in the description oh and if you think you can get exactly the same sound as the carolin solo from a software instrument let me know and if i think it's close enough i'll feature your work here in this channel distortion is an amazingly useful audio process and in this quick video i've only just scratched the surface of the possibilities i'm david meller course director of audio master class thank you for listening.

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