Getting Your Head Around FM Synthesis.

[legend4ry]

I was looking at the production bible and there wasn't a special part of FM synthesis and I remember there was this mad surge a while back of people wanting to get into building sounds using FM.. So lets get into the basics of this type of synthesis.


What is Frequency Modulation Synthesis?

Well, Wikipedia tells us.. "Frequency modulation synthesis (or FM synthesis) is a form of audio synthesis where the timbre of a simple waveform is changed by frequency modulating it with a modulating frequency that is also in the audio range, resulting in a more complex waveform and a different-sounding tone. The frequency of an oscillator is altered or distorted, "in accordance with the amplitude of a modulating signal."

I don't know about you but thats just some technical mumbo jumbo what only makes sense to a handful of people (who probably snort when they laugh).

Lets look at this video.

http://insidesynthesis.blogspot.com/200 ... art-1.html

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Welcome back, get your head around it? I hope you did but heres a basic breakdown for those who wasn't paying attention.




FM Synthesis works with a different set of rules to say, subtractive synthesis.

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It has two types of Oscillators - Modulators and Carriers.

Carriers carry the sound and its what you hear.

Modulators, modulate (change) the sound in the back end, you don't hear the sound of this but you hear the effects of it.

This is all a bit confusing but this guy can explain it better than me.

.

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Harmonic ratios explained

I am going to be digesting and rewording (for easier reading) this nice tutorial : http://www.sfu.ca/~truax/fmtut.html if you can get your head around fancy lingo then read the link instead!!

Intro

If you didn't know FM works with something called "Ratios" and "Sidebands" to produce harmonic (or inharmonic) ratios these are the relationship between the modulator and the carrier in frequency.

"When the frequency of the modulator (which we'll call M) is in the sub-audio range (1-20 Hz), we can hear siren-like changes in pitch of the carrier. However, when we raise M to the audio range (above 30 Hz) then we hear a new timbre composed of frequencies called SIDEBANDS."


Now if that didn't make sense, please watch the videos above then come back because it will after .


"Rule: for a ratio to be in Normal Form, M must be greater than or equal to twice C, or else be the ratio 1:1"

"The rule for determining harmonic/inharmonic is easy for Normal Form Ratios:

Harmonic N.F. ratios are always of the form 1:N, and inharmonic ones aren't.

Harmonic Ratios: 1:1 1:2 1:3 1:4 1:5 1:6 1:7 1:8 1:9


Inharmonic Ratios: 2:9 2:7 3:8 2:5 2:7 4:9"



I hope this makes sense.. To sum this up in simple terms.

Harmonic ratios are like multiples, 1 is a multiple of everything so any number it is attached to in the ratio of 1:X will be a correct multiple. These are how harmonic ratios work..

For instance..

1:9, 3:9, 6:9, 9:9 all work together nicely but
2:9, 4:9, 5:9, 7:9, 8:9 don't sound horrible but don't sound as harmonic.

Try it out and hopefully this helps a bit more.

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Building your first structured FM sound

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Freeware vs payware (and some shareware if I can find some?)

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Hopefully this clears up most of it for now and I will add more tutorials soon.. Just getting rid of my "drafts" ive saved on DSF as I have over 30 .. haha

[ctang]

quick question, in massive usually wave tables and filters are modulated, in FM would which would u modulate the carrier or modulater or both

[eldoogle]

I learned FM synthesis by practicing a lot.

[eldoogle]

quick question, in massive usually wave tables and filters are modulated, in FM would which would u modulate the carrier or modulater or both

Either.

[legend4ry]

quick question, in massive usually wave tables and filters are modulated, in FM would which would u modulate the carrier or modulater or both

Heres an easier way to look at it..


Tone > goes into [a] > [a] goes into > is now the end of the signal chain but [a] can modulate the sound coming out of > goes into [c] > modulations from [a] now go into then into [c] so can now modulate the signal coming from [a] as a separate entity, its another stage in the signal path [c] will carry all those sounds into the output.

etc, etc, etc.. Its not endless but it can get VERY complex, you can create a signal path where everything is modulating each other till eventually you set a signal to split from the loop into the out put.

So the answer is both

[3za]

quick question, in massive usually wave tables and filters are modulated, in FM would which would u modulate the carrier or modulater or both

Either.

You can modulate both the amplitude, and the pitch of them. Operators Can be carriers, and/or modulaters, they can also modulate their self (feedback).

Edited: for logic fuck up

[deadly_habit]

uploading the old documents folder from the sample swap had some fm stuff in there for ya
will edit the link into this post when it's done

link: http://www.mediafire.com/?qzz72p38lpyrbeq

[jrisreal]

pretty much all you gotta do is watch a couple tutorials and then try to figure it out on your own...

[ctang]

So i guess it depends on wether you like the sound at the end, because you can modulate the carrier for example putting an lfo on the entire sound, or you can LFO the modulater's amplitude or pitch.

Edit: Anyone know how i can modulate pitch or pitch bend in FM8? Kinda like in Massive where you are able to set an envelope on the pitch to either pitch upwards or downwards.

[RandoRando]

So i guess it depends on wether you like the sound at the end, because you can modulate the carrier for example putting an lfo on the entire sound, or you can LFO the modulater's amplitude or pitch.

Edit: Anyone know how i can modulate pitch or pitch bend in FM8? Kinda like in Massive where you are able to set an envelope on the pitch to either pitch upwards or downwards.

there is a pitch envelope in FM8 that controls the master pitch, but im trying to find how to change the amount of the pitch envelope, there is setting to change how much teh pitch bend affects the sound, but i cant find a setting for envelope, cause it seems like no matter how i do my envelope, its only like 2 or 3 semitones, barely enough to hear it at all

[ChadDub]

So I just started trying to learn Sytrus, and just by twiddling knobs and messing with the waveform editor I got some pretty decent results.

What I would LOVE to know now is harmonic ratios. Get on that ish yurd meh.

[legend4ry]

So I just started trying to learn Sytrus, and just by twiddling knobs and messing with the waveform editor I got some pretty decent results.

What I would LOVE to know now is harmonic ratios. Get on that ish yurd meh.

Done .

[ChadDub]

You've been holding out on us this whole time?

XD

Thank you, though. Really appreciate it. I LOVE Fm synthesis now, you can make so much shit with it it's amazing.

[legend4ry]

i just wrote it now .

[Fbac]

Posting so i can follow ;D

Whats synths people using for this? i know fm8 is populer. anyone on the ACE (u-he), phantom or Fmheaven?

[Ldizzy]

honestly fm8 is the shit.. ive never come across something as powerful and as intuitive...

i tried swapping it for a dx.. almost crapped my trousers.

[jrisreal]

Posting so i can follow ;D

Whats synths people using for this? i know fm8 is populer. anyone on the ACE (u-he), phantom or Fmheaven?

Sytrus FTW

[Fbac]

I poo pooed your sytrus comment at first .... then reasurched comparing it to Fmheaven,
both have 6 fm operators, both have mod matrixs, Fmheaven has 2 filters and sytrus has 3.
179 dollla for sytrus & fm heaven is 70 dollas..
So anyone tried Sytrus & Fm8 & uhe ACE ?

here are two tutorial videos i have yet to view: (will come back and edit later if there useless)
Reasen Video: http://www.thesoundofreason.net/reason/ ... hesis.html
ableton operator video: https://sites.google.com/site/mfalab/sy ... sis-videos

[RandoRando]

So i guess it depends on wether you like the sound at the end, because you can modulate the carrier for example putting an lfo on the entire sound, or you can LFO the modulater's amplitude or pitch.

Edit: Anyone know how i can modulate pitch or pitch bend in FM8? Kinda like in Massive where you are able to set an envelope on the pitch to either pitch upwards or downwards.

there is a pitch envelope in FM8 that controls the master pitch, but im trying to find how to change the amount of the pitch envelope, there is setting to change how much teh pitch bend affects the sound, but i cant find a setting for envelope, cause it seems like no matter how i do my envelope, its only like 2 or 3 semitones, barely enough to hear it at all

never mind, figured it out, i had to turn the amount knob in the the pitch envelope window

[-[2]DAY_-]

great thread just markin' it