Fathom Synth Development Thread

[Scrubbing Monkeys]

Also, this is off topic, but I’m asking it here among friends to get advice.

Yesterday I was just relaxing and was reading through the LennarDigital Sylenth thread here, and noticed amazingly that Lennard himself is a member here and still responds personally to many of the posts.

The Sylenth Filter is the Holy Grail of DSP analog emulating filter algorithms, and I’m dying to ask him how he did it, but it could be perceived as rude to directly request such a closely guarded company secret. Can any one offer me some advice on how to pose the question, such as “give me some pointers on what academic papers might deal specfically with Analog filter emulation.”

I’ve spent hours listening to that thing, and there is something going on that is much more sophisticated and fundamental than just adding an arctan non-linear function to the output. It sounds like a zero delay algorithm of some kind, but I can’t be sure.

Fathom already has the industry standard ladder and diode filter emulators, but to be honest, they still can’t even touch the Sylenth filter.

Filter diiscussion in progress.

viewtopic.php?f=33&t=495413

Not sure it helps but.....

[FathomSynth]

Yes, I think that's the same interview I already have the German translation for.

He talks about the filter but gives no hints for the algorithm, except that he developed it himself from the ground up.

But it's understandable. If I developed an algorithm like that, it would be in a titanium vault somewhere with a password as long as the source code.

[FathomSynth]

SM, Thanks so much.

I knew there was a thread like that somewhere here, but I was not sure where.
I think I'll post something there.

[Scrubbing Monkeys]

If I want to share a preset with a custom wavetable do I need to send the wavetable file as well?

[FathomSynth]

No, all waves needed by a preset are saved inside the preset including the ones needed by the wave table.

Also, if someone wants to use the wave table from your preset they can export it after they get the preset.

Heads up, I think I may do the sample and hold random modulator for the next release, so let me know if you have any preferences for the way that should work. I'm also hoping to make it run at the audio level as well as a random sequencer.

[nordickvr]

...Heads up, I think I may do the sample and hold random modulator for the next release, so let me know if you have any preferences for the way that should work. I'm also hoping to make it run at the audio level as well as a random sequencer.

Great!
Something telling me you'v already thought of a "smooth" option.

[Scrubbing Monkeys]

No, all waves needed by a preset are saved inside the preset including the ones needed by the wave table.

Also, if someone wants to use the wave table from your preset they can export it after they get the preset.

Heads up, I think I may do the sample and hold random modulator for the next release, so let me know if you have any preferences for the way that should work. I'm also hoping to make it run at the audio level as well as a random sequencer.

[FathomSynth]

I think so, I'm planning on providing a toggle for Step v.s. Continuous,
for both Amplitude and Time Period variance.

But just to be sure, tell me exactly what you would want by "Smooth".

[nordickvr]

I think so, I'm planning on providing a toggle for Step v.s. Continuous,
for both Amplitude and Time Period variance.

But just to be sure, tell me exactly what you would want by "Smooth".

Exactly what you just wrote, i.e. "Step v.s. Continuous".
"Morphing" in between would be great option too.
Slowly going from step-y/drastic to continuous/rounded-up.
Morphing would be luxury/extra.

[FathomSynth]

Ah I see exactly what you are saying.
Yes, I will make it so.

[Scrubbing Monkeys]

Can Fathom do "sync". One oscillator will restart the period of another.

The may be very obvious once someone points it out to me.

Also, can Fathom's Oscillators be free running.

Again this may be very obvious. I do not have it in front of me. Song starts it on host beat. Note starts it at the press of a key or midi note. Is there ever a point that it is running free?

Hmmm......... well I thought about this for a moment. Song and Note refer to modulator starts. I guess its not really possible for a vst to have true free running Osc with out constantly running in the back ground. Most that claim free running actually just start at a random phase. Does Fathom do this?

[FathomSynth]

Yes to both the first two questions. Fathom can exactly sync ALL the oscillators, and Yes, the oscillators can be truly free running. However, no, they do not run in the background when idle.

In more detail. Oscillators and modulators technically are both oscillators, but they work a little differently.

Fathom's audio oscillators always run in one of two modes: Trigger Note, or Free, controlled by the "Trigger" toggle on the Detune page of every oscillator. Each voice that plays a note, is actually a collection of detune voices, that are totally independent, each running its own code thread.

If an oscillator has Trigger set to Note, all the detune voices within a single poly voice will always start at waveform position zero, when the voice note is first pressed, even if the voices are detuned in relation to each other. This creates the soft "pow" when the note starts, just like a hardware synth with trigger set to note. As the note voice plays, if the detune voices are detuned, they will quickly diverge slightly in pitch until the steady state is reached.

Furthermore, all oscillators in the instrument with Trigger set to Note will be exactly synced at the start of each voice note. In addition, all oscillators with Detune disabled and playing mono, have their waveforms exactly synced permanently so they all play as one oscillator with no phase cancellation.

Conversely if an oscillator has Trigger set to Free, it runs freely with no relation to any other detune voice, always obeying only its own detune parameters for pitch. When the voice stops after playing a note the oscillator picks up where it left off in phase when it starts a new note, so it always stays free running. As a matter of fact, when the oscillator is first added and plays its very first note, if Trigger is set to Free, the detune voices are spread out evenly in phase before the first note is played so the first note starts out truly free.

However, out of respect for the efficiency of other plugins on other tracks, Fathom does not play its free voices in the background while idle.

Modulators work in a similar fashion, except Free running is replaced with Song sync. If a modulator trigger is set to Note, an independent copy of the modulator runs on each polyphonic voice and starts its graph envelope at the start of the voice note. If set to Song the modulator runs as a single entity for all voices and is synced exactly to the song position.

Furthermore, Fathom modulators, when synced to song, do not run using their own timers, they are synced exactly down to the individual sample to the exact song sample count which comes in with each host block. This way you never have to deal with the unpleasant hurdle of somehow clearing modulators with timers that have gone out of sync with the song, like with some other synths. This was done so that 16nth note rhythmic modulations, often used for EDM, Trance and Rave music and the like, can have stacked modulations and remain absolutely precise and clean in relation to all the other tracks.

[Scrubbing Monkeys]

Thanks for the detailed explanation. Ya know...I didn't even think about the detune parameters. I kinda think of those as extra waves but I guess the original is in there too. That makes since.

How would one set up the "sync" effect used on older analog synths? Where the master oscillator restarts the slave oscillator at the end of each cycle regardless of the frequency of the slave oscillator? The effect sounds kinda like PWM with more edge.

[plexuss]

First, what a great find Fathom is! I just stumbled on this thread and tried the demo (mac/logic) and am very impressed. Even better is the price! Wow. Instant purchase... except... when I tried to use paypal I got this error from paypal "Sorry, we can’t complete your purchase at this time. To comply with government regulations, this transaction has been declined."

Weird. So I used a credit card.

[onerob]

Bought this. Couple of quick thoughts:

1) It would be nice to see a more intuitive way of deleting modulators from the modulation list.

2) Better preset management.