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Frequency Drifting w/ Multiple Value ?!?

Dr.Synth
I checked this multpile times to make sure this was truly occuring -- the frequency of the Operators gets slightly sharp as you increate the Multiplier value. The discrepency increases with higher multiplier values.

Take the init patch & configure as Op 3->2->1(carrier) Set Op 3, 2 waves to Saw2, Op1 to Sine. Op 3 Vol= 22, Op 2 Vol = 30 Op1 = 127. Turn off all velocity sensitivity.

Play the C one or two octaves below middle C. With all Ops at Multiplier = 1, the timbre is absolutely static. Change the Multiple for Op 3 = 2. Hold the note, you'll hear the timbre harmonics start to drift very slowly. Change Op 3 Mult = 3 and the drift is faster. Gets proportionally faster the higher the multiplier.

It can almost, but not quite, be corrected by setting the Freq Fine value of (negative) Multiplier - 1, i.e. if Multiplier=3, set Freq fine =-2

It appears that the Ops lose their Freq lock when the Multiplier vale.

Can you please confirm? All Ops are Fixed phase...

Manny
KODAMO
Hello,

This is normal, this is due to the way frequencies are handled in the FM engine, it has been discussed here: https://kodamo.org/forum_topic.php?id=128

That will happen or not depending on the note frequency and ratios between operators.
Dr.Synth
Thnx for the link reference... Interesting behavior, not something I've seen in other FM implementations.

Is this something that will be just be a characteristic of the Essense? Or is it something that can be addressed in the future?

In some cases it is a nice variation from the normal, in other cases it 'breaks' a sound.

Manny
KODAMO
It will most likely stay as a characteristic of the EssenceFM.
Playing static tones for seconds is almost never wanted, and if you really want that you can simply use a custom waveform with the harmonic content of your choice.
usw
The fact the the beating gets faster as the multiplier value is increased looks more like a rounding error that gets amplified rather than an unavoidable one...imho this should deserve a full investigation :/
EP
I think this issue is actually such a topic that it deserves everyone's attention.

Here is a test to perform:
Set up a simple FM pair with c:m ratio = 1:2 and a third party spectrum analyzer.
Set modulator's output to 0, disable velocity sensitivity for both operators.

Play a C3 and see your fundamental on the spectrum analyzer, at around 130 Hz.
Bring the modulator output to 30, watch the different frequency components appear.

If you hold the note for a moment, you'll see (and hear) the amplitude of the fundamental vary a LOT.
This finally explains to me why Essence FM seemed to have significantly less low end than FM-8 or Dexed.

If you set the c:m ratio to 2:4 , and the modulator 'fine' parameter to -1 and play the same note on your keyboard (so it will sound one octave higher), the sound will stabilize.
Do the same one octave higher on your keyboard ... it gets worse.

Appart from the obvious (making a simple patch becomes exponentially more cumbersome, defeating the Essence FM's promise),
Here are my reasons to consider it a problem that has to be addressed:

1)The exact value for the 'fine' parameter to compensate for this issue will not always be an integer ( as with the 1:2 ratio),and different for different notes, making total stabilization impossible.
2)Because perfect ratio's will not be achieved, playing with the modulator's phase will not yield the expected result.
3)People choose digital synths for the accuracy, the precision. Those after instability will get an analog synth.
To say that a 'broken' engine gives character to a synth is making a bug look like a feature.
If the engine was fixed, and the user still wanted this behavior, he could then use the 'fine' parameter to easily recreate it.

I hope users and developers will chime in.
I understand that fixing the problem would take quite a bit of 're-thinking',
and the solution could possibly consume more processing power, possibly limiting the polyphony or other features.

That being said, I really hope Kodamo will do the right thing and not let us with an expensive broken synth.
Speaking of developers, the code of Dexed is open source and therefore freely available. This synth doesn't exhibit this problem.
EP
Since I wrote my post, two users put their Essence Fm for sale on the Facebook group.
I don't know if it's related, but I think it is a possibility.
I also think that this issue is compromising Essence Fm's future, and the VFM's as well.
I'm sorry for Kodamo, as this situation is likely not a part of their roadmap.

I'm keeping my Essence Fm for now, because I think this issue is sortable.
I have hope that I'll be able to use it to enjoy full fm synthesis.
Time will tell.

I hope the Kodamo team will chime in and tell us if they have plans to seriously look into it.
KODAMO
We tried with higher precision oscillators recently, but all patches sounded worse because their harmonic content were suddently more static.
The EssenceFM was mostly designed by ear, like a musical instrument, to sound good. Not to follow a perfect mathematical representation of what FM is in theory.

Now that does not mean we won't add an option for "extra precision" on oscillators someday, but I'd like to temper your message by adding that these choices are what make synthesizers unique. Many of them may have oscillators named "Saw", but they all sound different. Same goes for the filters, for the way envelopes works, and the way FM is achieved. In most cases, the current behavior is desirable as you'll get more lively and organic sounds than on any other FM synth.
Dr.Synth
As I responded above, In some cases that Ratio ptich behavior is a nice variation from the normal, in other cases it 'breaks' a sound, and is extremely frustrating. Thus EP, I see your perspective, as I see Kodamo's.

I look at it from the perspective what can the Essence FM do that my other FM synths cannot, and embrace those areas. I'm not focusing on what it can't do compared to other FM implementations -- i.e. I'm not looking at the 'quirks' as negatives but as possibilities for a different approach to discover different sonic behaviors & flavors that I can't do on other platforms.

There's no 'ideal' FM engine out there yet, so I wouldn't be getting rid of my SY99's, Montage, Hydrasynth or Iridium anytime soon, even if the EFM Ratios had 'perfect pitch' :) All those instruments do some unique things, as well as having their own annoying quirks.

Do I prefer that instability was my choice? Absolutely! But I'm getting things out of the Essence I can't get with my other gear, and it is becoming a very worthwhile instrument for me.

Kodamo is commited to improving it, as seen with all the changes in the latest firmware, so I anticipate as they noted a future 'high precision' mode at some point.

Manny
Sascha
I absolutely agree with EP on his points.
I ordered an EFM a few weeks ago and am still waiting for delivery. I've been really looking forward to it until now, but after reading about the instability, I'm having second thoughts and wondering if I should cancel the order.
For me, the important thing is that the instrument is precisely programmable, all organic fluctuations I would like to add myself and decide on it.
Dear Kodamo team, I would like to know if there is hope that these things can be fixed in an update?
I am now a little unsettled...
A "high precision mode" is very welcome.


Je suis absolument d'accord avec EP sur ses points.
J'ai commandé un EFM il y a quelques semaines et j'attends toujours la livraison. Je l'attendais avec impatience jusqu'à présent, mais après avoir lu des articles sur l'instabilité, j'ai des doutes et je me demande si je ne devrais pas annuler la commande.
Pour moi, l'important est que l'instrument soit précisément programmable, toutes les fluctuations organiques, je voudrais les ajouter moi-même et en décider.
Chère équipe Kodamo, je voudrais savoir s'il y a un espoir que ces choses puissent être corrigées dans une mise à jour ?
Je suis maintenant un peu déstabilisé.
Un "mode haute précision" serait le bienvenu.
Soarer
This is really quite outrageous and a strong exaggeration. A nearly infinite range of fine sounds can be made with this synth and a tiny bit of drifting won't change that. If I need a spectrum analyser to detect this problem there isn't one in practice. It's fine to point out a behaviour or issue like this like Manny did but saying that it's compromising Essence Fm's future and that people are selling their synths because of this is really unfair and pretty foul.
Kodamo please don't sacrifice EFM's lively and organic sound in order to solve this. Every synth and piece of gear has it's quirks but you can still make great music with it.
Anyway, I know what this synth is capable of (excellent sounds!) and I'm very happy with it so I have no worries about this at all.
Strider
What a wankfest... Go make music with this amazing machine and stop obsessing about tiny details.
EP
Wankfest would be more appropriate to describe a group of grown ups who favor hype over reality.
So much love until internet shows you the next thing you absolutely need in your life...

For those who don't like spectrum analyzers : you don't need one.
Just reproduce the test I detailed, and you'll hear it, even if you're the type of guy who believes 'high precision oscillators' are required to deliver the normal precision of old vst's.
Of course, if you really believe this bug was made on purpose for artistic reasons,
or if you believe that losing amplitude on the fundamental of your tone (=low end) is a tiny detail, then you might not be able to hear it.

If I hurt your feelings, here is a happy smiley : 🙂
Soarer
Maybe if you guys keep insults out of the discussion we can actually talk about this. I don't know what you mean about the internet showing you the next thing - I intend to use the EFM for many years to come, that’s why I invested in it.

Anyway I do hear the drifting in your example but still fail to see the how it is worth such negative statements. If it can be solved then that's great as long as sound quality and character is not lost. I wouldn't keep this synth if it started sounding like a flat and lifeless VST instrument.

Most often this drifting is something you would program yourself isn't it? Which type of sound is it that suffers from this issue?
No matter what this issue means, the many sounds - pianos, pads, synths, drums, basses etc., I've made sounds absolutely fine and are completely unaffected of this. That’s why I say that in practice this doesn’t really matter but I do see that in some specific cases it may affect your sound.
DX100
I agree 100% that the oscillators should track correctly!
This is even more crucial when one is using different tunings.
KODAMO
The "drift" is way too low to create any noticeable pitch difference - this only creates slighly moving harmonics when modulating operators, which in most cases, is desirable.
We'll now close this topic, an optional feature to get higher precision may come but it's not a priority. As stated, music is more important and all synths have different behaviors, that's what make them unique.