In this FM8 Beginner Tutorial we explain although it was heavily used through the history of electronic music, FM Synthesis still hides potential which is further expanded by modern implementations such as the one in FM8.

This is short fm8 beginner tutorial to FM synthesis with NI FM8.

Understanding the fm synthesis in theory would require quite complex math so I will instead concentrate on more practical approach. Fm synthesis is believed to be hard to grasp but I assure you that with basic understanding of the principles behind it, it’s not that different from normal subtractive synthesis.

It sure requires a bit of a different mindset from that needed for subtractive synthesis and the main difference would be that in subtractive synthesis you build sounds from combining different individual elements (like oscillators, filters, vcas, etc) while the fm synthesis works trough interaction of basic building blocks called operators.

As one element changes in relation to the other, the changes in timbre are produced.

I also believe that fm synthesis is considered to be complicated because it offers such an immense world of possibilities and nuances in sound that makes it appear so difficult.

Also, f you do not understand the very basic principles behind it can be very confusing so the aim of this first tutorial is to teach you those very basics.

After this tutorial I will concentrate on more practical examples on how to create certain sounds, also sound design for dance music.

We will create leads, bass sounds, fxs from a scratch and hopefully after that you will be able to see how powerful technique fm synthesis can be.

Now let’s get to work.

We should start with a simple sine tone.

Although FM8 offers a wide range of different waveforms the original FM synthesizer works only with sine oscillators.

So how do we introduce some harmonics in a sound without changing the waveform from default sine wave?

We do that by either modulating our oscillator by another oscillator or we can modulate oscillator by itself.

Oscillators in fm synths are usually referred as operators.

The main operator which is producing tone we hear is called carrier and the ones modulating our carrier operator are called modulators. Modulators aren’t normally connected to audio output so we don’t hear them directly instead they are only frequency modulating carrier oscillator.

That modulation is producing additional harmonics in our tone from which we sculpt our sounds.

Go into the Osc tab found under the pitch and modulation wheel. Now you are looking at oscillator matrix. At the moment there is only F operator active.

This will be our main sound source and it will act as our carrier operator.

If we click on the Spect tab which is found right under the pitch and mod wheel we are able to see our oscillator spectrum.

We see there is only one fundamental frequency showing which is expected since we have only a sine wave at the moment.

Now put your mouse in the operator matrix on the bracket right above our F oscillator. Click and drag upwards and you will see a number appearing above the F operator. This is the amount with which the oscillator F is feeding back to itself.

As we slowly drag upwards we hear our tone changing from simple sine to a saw like wave in the middle value range up to almost noise like frequencies in highest values.

Take a close look at the spectrogram to see how it is changing and adding harmonics.

Here you have your first non sine tone out of a fm synth.

Now we have to add some interest to our tone.

Normally in subtractive synth you would now introduce the filter to emphasize or subtract certain harmonics in your starting waveform and add movement to the sound.

Although you can do that in FM8 with its filter and sound shaping capabilities the original fm synthesizer didn’t use filters.

For the sake of this tutorial lets stick to the more traditional fm synth approach and avoid using the filters for now.

Set the amount of self modulation to just over 50 percent. You should hear a nice saw wave like tone. If you click on F oscillator you will see the control page for that particular operator.

In the amplitude section of the control panel you can see level fader which represents the maximal amplitude of chosen oscillator. There you can also see the graphical envelope which is exclusively controlling the amplitude of our operator. There is no difference if we use our oscillator as a carrier or a modulator, that envelope always controls operators amplitude.

Also, the max possible value of the envelope corresponds to the maximum amplitude value set by the level fader. And since we are looking into carrier oscillator this also controls the audio output level.

If we would be looking at the modulator oscillator this would then correspond to modulation amount as we will see in a minute.

Now we have our tone lets introduce another operator by right clicking the operator E.

We have activated it but it isn’t connected to anything for now. Now place your mouse in the same horizontal row as operator F but under the operator E. Again, by dragging upwards you create connection between our two operators. Set it to 66 percent and also change the value of self modulation on operator F to 25.

Now we still hear only our carrier operator F directly but we also hear the frequency modulation effect operator E has on operator F.

That produces sidebands around the carrier frequency of operator F so even more additional harmonics are introduced which results in richer harmonic spectrum.

Now here is where things are starting to get interesting. If we change the amount of operator E we can hear how our sound spectrum evolves.

Double click on operator E and it will take you to the control page. Change the envelope of operator E.

Remember that the highest possible level of the envelope now corresponds to modulation amount you have set for modulator E modulating operator F.

Set an envelope like the one in the picture by dragging the respective points.

When you stretch the envelope outside the view region just double click in the empty background and the view will automatically snap to your whole length of the envelope. Play a few chords on your keyboard. Now you probably understand why there are no filters needed in fm synth.

You can change the spectrum and introduce tone variations just by changing the amplitude of a modulating operator and thus introducing the variety in timbre.

But luckily things don’t end here, you can go really wild from this point on. Imagine one operator modulating the next operator which is modulating carrier operator. Or maybe two parallel modulators modulating the carrier at the same time.

What about two carriers, one modulator which modulates two other modulators for each of the two carrier operators? You see where I’m going here?

This operator configurations or chains we call operator algorithm and they are the very heart of every fm sound. And the best thing in FM8 is that it comes with a huge pre-programmed bank of algorithms.

To try them out just click on the tab above the operator matrix which will open drop down menu from which you can choose different algorithms.

Have fun!!

At the default state all operators are operating at the same frequency.

That is of course the frequency of note you play on your keyboard. Because of the complex math behind it I wont go in further explaining the process but to keep sounds in tune we must change operators frequency relative to each other.

We must change them in simple integer ratios which we also call modulation index. And as long as we keep them in a simple integer ratios such as 2:1 the sound will keep its original fundamental tone. Now let’s go to the controller page of operator E which acts as a modulator in our case. We see the number representing the ratio of 1.

That means that both of our operators works at the exactly same frequency of a note played thus the ratio between our carrier and modulator is 1:1. Now change modulator E ratio to 2. This multiplies our modulator frequency by two, an octave higher in musical terms.

This also means that our ratio between carrier and modulator changes to 1: 2 But nevertheless the fundamental tone of our carrier operator stays the same because only the sidebands produced around our carrier frequency changes which results in different harmonic components of our sound. And this is another great feature of fm synthesis, you can create rich tones and strong modulations without loosing the fundamental tone.

If we want to introduce some detuning you can either change the offset value for few hertz which will create slight detuning.

Alternately you can change ratio value to a non integer number lets say 1.9500. You can hear interesting effect which produces really nice detuned tone. If we change the value even further we create non harmonic sidebands that are less related to our fundamental frequency and the tone slowly loses its musical value.

On a large scale by changing the ratios of either the modulator or carrier to non integer values one can create rich pallet of textures, noises and other unearthly sounds.

I hope now you see the great potential behind fm synthesis with this fm8 beginner tutorial.