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FM modulation unwanted artifacts
Posted: Sat Dec 12, 2015 6:34 am
by Father
How would you eliminate the noisy artifacts when doing a simple FM setup like the example?
Is this the right way to do it at all?
Re: FM modulation unwanted artifacts
Posted: Sat Dec 12, 2015 11:37 am
by Spogg
Hi Father
I believe the noise is caused by wavetable switching inside the Prim. If you set the FM knob to a low value the noise goes. A set of wavetables is created by the Prim to limit bandwidth based on the base frequency selected for the note played. With a wide FM excursion in the Freq input the Prim will be selecting different tables rapidly.
The more usual approach is to modulate the phase. This means altering the readout rate from a single chosen table and the sound is the same but without wavetable switching.
I've Spogged your schematic: Changed the FM input to the Phase input and changed the FM knob to go between 0 and 1 and to my old Vulcan ears the result is good.
If I'm wrong about all this I'm sure someone will let us know!
Cheers
Spogg
Re: FM modulation unwanted artifacts
Posted: Sat Dec 12, 2015 4:28 pm
by Father
Aha didn't know that.
Yes sounds good enough i think, and its very similar to the old one which is good.
Thanks so much
Re: FM modulation unwanted artifacts
Posted: Sat Dec 12, 2015 8:19 pm
by Father
Still happening, specially with different waveforms its more obvious and annoying.
Does this happen only with wavetables?
Re: FM modulation unwanted artifacts
Posted: Sat Dec 12, 2015 10:00 pm
by martinvicanek
Re: FM modulation unwanted artifacts
Posted: Sat Dec 12, 2015 11:47 pm
by Father
martinvicanek wrote:It's a bug;
Oh man that's too bad.
Re: FM modulation unwanted artifacts
Posted: Sun Dec 13, 2015 12:03 am
by martinvicanek
Not necessarily:
1. You can use algorithmic oscs that allow through zero FM
2. Now with the new 3.0.9 features we can build our own wave reader
Re: FM modulation unwanted artifacts
Posted: Thu Dec 17, 2015 1:11 am
by Father
martinvicanek wrote:Not necessarily:
1. You can use algorithmic oscs that allow through zero FM
2. Now with the new 3.0.9 features we can build our own wave reader
1. Not following you, a quick example would be great if you have the time.
2. Thats nice. Well have to upgrade for that.
Re: FM modulation unwanted artifacts
Posted: Thu Dec 17, 2015 7:55 am
by martinvicanek
Father wrote:1. Not following you, a quick example would be great if you have the time.
Scroll down...
Father wrote:2. Thats nice. Well have to upgrade for that.
Not sure it is stable yet.
Re: FM modulation unwanted artifacts
Posted: Thu Dec 17, 2015 4:06 pm
by Father
Nice stuff. the polyBLEP Saw Osc sounds clean! (I think hehe). I just wish it was a wave table read
Any chance the bug gets fixed on next update?