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FM7 fm synthesis ?
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MeditationProfonde
IsraTrance Junior Member
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Posted : Dec 11, 2009 23:13:07
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In the NI FM7 manual, in the chapter about FM synthesis and FM programming there is written that oscillators modulate the other's amplitude, so that's AM ...
Where is the error ?
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Ascension
IsraTrance Full Member
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Posted : Dec 12, 2009 01:54
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MeditationProfonde
IsraTrance Junior Member
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Posted : Dec 12, 2009 08:44
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What a goof, a whole chapter explaining that their FM vst is based on AM modulation ... They even say that little modulation values make tremolo, which is AM. |
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Trip-
IsraTrance Team
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Posted : Dec 12, 2009 08:56
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Modulating other target's amplitude doesn't imply it is AM based. AM is when you use amplitude as a modulation guide - changes in amplitude create the modulation.
Please explain more if you meant something I didn't understand.
NOTE: this topic is not strictly about FM7. Crackling universes dive into their own neverending crackle...
AgalactiA |
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Speakafreaka
IsraTrance Junior Member
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Posted : Dec 12, 2009 11:18
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FM7, like all of the DX style FM synths work on Phase Modulation.
Phase modulation does indeed alter amplitude of the waveform by modulating the point of the wavecycle that is getting played at a specific time.
What the FM7 does not do, nor any FM synth that works on the same principal, is route one oscs output to the frequency of anothers, as is typically meant by 'FM' on say a classic analog synth.
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http://www.soundcloud.com/speakafreaka |
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MeditationProfonde
IsraTrance Junior Member
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Posted : Dec 12, 2009 17:31
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Are you sure of that ? If find very strange that they call frequency modulation "phase modulation" which IS NOT frequency modulation. Are there synths that are really frequency moduled ? |
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MeditationProfonde
IsraTrance Junior Member
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Posted : Dec 12, 2009 18:44
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hmm in fact phase modulation is a case of frequency modulation. |
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Speakafreaka
IsraTrance Junior Member
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Posted : Dec 12, 2009 20:36
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Completely certain.
I've built synths that work both the PM and FM (and AM and RM) way.
Think of it this way - when you play a note on a digital synth, what you are really doing is controlling the rate that you read through phase positions of an oscillator. The faster you cycle through the positions linearly, the higher the output pitch.
However, when you modulate the readthrough rate in a nonlinear manner, then you change the output waveform. If you modulate with oscilator which runs at say twice the freq of the carrier osc, then you impose the modulators two cycles onto the carriers one - which will be audible.
This is difficult to achieve in the same way on analog synths which typically do not work in this wavetable manner and do not offer such precise control of phase. *rule of thumb* and FM synth will be based on PM, whereas a synth with FM between two oscs will more likely be proper FM, although this most certainly is not always true, by any stretch of the imagination. .
http://www.soundcloud.com/speakafreaka |
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