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Messages - SMF

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preenfm2 and preenfm3 / Re: 2.12 Beta 2
« on: July 04, 2020, 08:24:31 AM »

I tried 2.12 Beta 2 and CC7/CC10 do work like a treat! Very, very nice!

But it seems like I stumbled across a bug when selecting banks/patches in the DX7 section. If I do accidently select patch Nr. 33 then the PreenFM2 freezes on playing the current waveform and needs to be restarted for recovery (my sequencer starts numbering patches at Nr. 1, so this is exactly one patch above the allowed range for DX-7 banks -- just for clarification. This looks like a missing range-check leading to out-of-bounds memory-access at a first glance.).

With PreenFM2-banks, however, this doesn't happen.

preenfm2 and preenfm3 / Re: 2.12 Beta 1
« on: July 03, 2020, 09:31:13 PM »
For CC10, I see, that's the reason i created the "Mix" Filter (that's the first one) and its "Pan" parameter, but when using it you cannot use any other effect.
It would have to be a feature available through CC only as i don't find any nice place to put that in the already crowded UI.

Having this available through CC, only, would be -- at least from my point of view -- absolutely perfectly OK.

I must admit, that I do not know of any synth which features more than this (Channel-Pan only via CC10). I may be wrong but I believe that there is pretty much no synth out there having it directly accessible from within the UI...

preenfm2 and preenfm3 / Re: 2.12 Beta 1
« on: July 03, 2020, 08:13:03 PM »
Why doesn't the MixerGain (CC73) work for fade-in and fade-out ? It's available even when no filter is selected.

According to this List: CC73 is "filter-gain" and not "mixer"-gain.  ;) This is why I didn't even think it would work without a filter being set.

Now, that I have tried it, it seems very well suited for the job. Only weird thing remaining in that context is, that it is on CC73 (just curious, was there any particular reason for this?) and not on CC7 (which would be Midi-Channel-Volume).

According to that same Midi-CC-List for the Preen (is it complete?) CC7 is not used. If so, would it be possible to double CC73 on CC7? So, that the PreenFM2 would react on both? CC73 for backwards-compatibility and CC7 for all sorts of "Standard"-Midi-Sequencer-Software? CC7 for Channel-Volume is pretty much an agreed standard...

And can you clarify what you mean or want to achieve with "stereo-separation" ?

I will try to...

You can place the output of the four mixer-channels of a given PreenFM2-Voice in the stereo-position separately -- which is a very cool feature, btw -- like you can do with the separate audio-levels of these. This is (according to the list mentioned above) controlled for the pan-position of each mixer-output with CCs (23 + (n-1) *2), and for the volume of each mixer-output with CCs (22 + (n-1) *2). So CC22 would control Mix1-Volume and CC23 would control Mix1-Pan-Position... This text is just an attempt to clarify of what I am speaking about (you will know these CCs by yourself for sure... ;) )

What I would like to have additionally would be some means of a "global" Pan-Position (Standard-CC for this would be CC10).

So what would be the desired behaviour of CC10? Imagine CC23 (pan MIX1) is set to totally left and CC25 (MIX2) is set to totally right. CC10 then would be reacting as follows: CC10 set to left: MIX1 and MIX2 mapped completely to the left position. CC10 set to right: MIX1 and MIX2 mapped completely to the right position. CC10 set to center: MIX1 left, MIX2 right as set by CC23 and CC25.

Why do I bother and ask?

I use the preenFM2 mainly in a DAW-Sequencer-Setup in which I use all four of its midi-channels with different instruments. Most DAWs/Midi-Sequencers provide Channel-Volume and Channel-Panning on CCs Nr. 7 and Nr. 10 inside of some sort of channel-mixer in that scenario. And "all" (despite the Waldorf Rocket ... which is monophonic and doesn't feature midi-controlled volume at all...) my synths feature them on these CCs. Except the PreenFM2.

all the best,

preenfm2 and preenfm3 / Re: 2.12 Beta 1
« on: July 03, 2020, 08:51:20 AM »

I use the PreenFM2 quite a lot for my music. A real annoyance is that it does not have channel-volume and channel-pan. (At least not on the standard-CCs) So I have to use filter-gain or the CCs for the mixer to achieve the desired changes. While this is nice if you want to alter the sound and stereo-seperation completely, this is totally annoying if you just want a fade-in and/or fade-out.

So, please, make these midi-CCs (Channel-Volume/-Pan) work, before adding more filters or other more CPU-intense but seldomly used things.

all the best and TIA!

preenfm2 and preenfm3 / Re: Yellow OLED : high frequency solution
« on: April 08, 2020, 06:16:50 PM »
Additionally to the thick, single layer grounded aluminium-shield which was already inside my preen, I dersperately added 216 Layers of aluminium-foil like discribed in the initial post by Xavier. This was just the maximum I could snuggly fit in between OLED-Module and Preen-Mainboard. These layers are not connected to anything and remove ANY(!) spurs I still had in the output.

I can measure down to -120dBFS and there is plainly nothing left. So, to me it seems like all spurs I had were related to the OLED-Module. It also seems to be just the magnetic field produced by the Buck-converter (PSU) on the module. Most probably (but I don't have a need to give this a test-run for now) ferromagnetic material (multiple thin iron-sheets) would be better suggestion for a shield against the magnetic field than using aluminium.


preenfm2 and preenfm3 / Re: Yellow OLED : high frequency solution
« on: April 08, 2020, 02:12:00 PM »
My version (R5d) has the OLED mod applied (22 Ohm Resistor), it even has this marked on the PCB ("OLED = 0 or 22 for OLED MOD")... and there is a (grounded) shield in between the OLED-Board and the Preen-Mainboard. But still I have a significant(!) amount of this high pitched tone in my recordings (-60dBFS is not really near being acceptable for me)...

Any suggestions?


I'm not too sure of this one but could it be that I found a bug/glitch in the pitch-wheel-processing of 2.10? Pitch-bend-messages seem to be not followed in the full range.

What I expected:
Midi-Pitch-wheel-Messages are followed in the range of +/- 8191 values.

What I found:
Midi-Pitch-wheel-Messages are followed in  the range of (aprox.) +/- 1280 values.
There is some uncertainty in this value -- therefore the "approx." -- because I have tested this from within a DAW and "by ear" until there was no audible change any more.

How to reproduce:
Create patch mapping pitch-bend to all-osc-freq (or all-osc-freq-harm) and create a pitch-bend-transition with your favourite DAW in the range of +/-8191.


preenfm2 and preenfm3 / Re: Basic waveforms with FM
« on: August 12, 2019, 05:34:39 PM »
Hi Xavier,

FM needs a low pass (few HZ) after operators to avoid this pitch shifting.

when I read this for the first time (in an older thread), I assumed it was a typo, but as you repeatedly say it's a low-pass filter, I am curious now... because for all what I recall, it is a high-pass filter which is required to get rid of the DC-component of the resulting spectrum in case of FM (PM does get rid of the DC-component inherently)...

So, if you really use a low-pass filter in between the operators, then I assume that it might be used to isolate (integrate over) the DC-component from the signal and then subtracting it from the next modulator-input? If so, then you turned the low-pass into a high-pass in this way...

But I may be misunderstanding what you actually do there.

all the best,


I have a question regarding the modulation of the frequency of a modulator...

Is it possible to quantize the frequency of an oscillator/operator with preenFM2? That is: Say, you have an LFO and use this to slowly modulate the frequency of an oscillator. The result normally will be a smooth transition from factor 1.0 over 1.1 over ... to a factor of -- say -- 4.0. Is it possible to leave out the fractional parts? So, that wathever the LFO-Value is, the resulting frequency-ratio of the oscillator is strictly non-fractional? (It should ramp up and down in octaves... and BTW I chose an LFO in this explanaition but this is not my primary intention. I would like to use velocitly or the free-env as input-source for this...)

Many thanks,

preenfm2 and preenfm3 / Re: Share your creations using the PreenFM2!
« on: July 14, 2019, 06:45:21 PM »

so I have played with my preenFM2 this weekend, too. I think the result is quite decent for a first attempt in creating new FM-patches after some years now...

I hope you have as much fun listening to it as I had when I created it. And, Xavier I really love this little synth -- albeit I must admit, that I have not a too good understanding of how to manage banks in it. But...

many thanks!

preenfm2 and preenfm3 / Re: Basic waveforms with FM
« on: July 12, 2019, 01:28:19 PM »
Hello again,

I have made a measurement of the preenFM2-output (noise is due to digital amplification to make it fit the simulated data in gnuplot. Despite a 13-16 kHz whine at -60dB -- the OLED? -- the output is dead clean) and compared it to

a) a 3OP-PM sawtooth-approximation without a phase-shift in between the carriers and the modulators


b) a 3OP-PM sawtooth-approximation with a phase-shift of pi*0.5

One clearly can see, that (b) is quite close to the output of the preenFM2. The differences -- I think -- mostly come from the frequency response of my audio-equipment which will of course distort the signal a little bit.

This should clarify what I meant with "phase-delay" in the last postings.

To explicitly say this: Both variants (whith and without the phase-difference) absolutely sound the same and have the same spectral distribution. Only the waveform on the oscilloscope will differ from the expected result. So, basically this is nothing to worry about...

On the other hand side: This result makes me really think that it might be a good idea to (maybe via a flag for backwards-compatibility?) switch the preen over to use PM (as most (all??) other "FM" synths do). It's using PM anyways, now...
With this change it would produce the expected waveforms from the various tutorials and it would (most probably) save some CPU-time to calculate...

For me personally it was just irritating. The sound and the flexibility of this nice little monster is outstanding! I love it, so many thanks Xavier!

all the best,

preenfm2 and preenfm3 / Re: Basic waveforms with FM
« on: July 11, 2019, 11:06:25 PM »

after some further experiments... Could it be that there is a highpass-filter in-between the carriers and the modulators (in-between every modulator-carrier-link... so there should be quite a lot of them)? This could explain the observed phase-shift. And if so, this would effectively implement phase modulation instead of frequency modulation because of using the derivative of the modulation-signal, then.. wouldn't it?

If I'm not missing a point here, wouldn't it be "better" in this case to directly use PM and to save some CPU-cycles by avoiding the HP-filters (maybe to increase sample rate or polyphony or for allowing feedback)?

all the best,

preenfm2 and preenfm3 / Basic waveforms with FM
« on: July 11, 2019, 02:03:30 PM »
Hello all,

so I am the proud owner of a preenFM2 now... And I try to get accommodated with its FM-synthesis (this is not the first FM-capable synthesizer I use, btw...), so I thought it would be fun to do what I have done on many FM-synths before: creating baisc waveforms with FM (saw, tri, square, pulse) to get an understanding of it's parameter-range and response...

But whatever I try I can not even come close to a synthesized 2-OP approximation of a sawtooth-waveform?!? hmm,... The spectrum looks right, so I guess there is some sort of phase-delay inside the operators, maybe?

BTW: just curious, but what was the reason for not using phasemodulation but real FM?

many thanks,

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