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91
PreenFM2 / Re: Ableton Midi Issue
« Last post by gorasou on October 04, 2018, 11:44:05 PM »
Never mind, I think I found a solution. I set receive and send to NRPN only and it seems like it fixed it. apparently there was some cc action going on wich threw some of the parameters off. now everything reacts smoothly
92
PreenFM2 / Ableton Midi Issue [Resolved]
« Last post by gorasou on October 04, 2018, 11:00:01 PM »
Hey everyone!

Just got my Preen from Van Daal  a couple weeks ago and I really love it! I found a really weird issue though when using it with Ableton Live (latest version).
I use the Editor wich works great but for some reason whenever I have Ableton running and the Preen connected (midi in and out via the 5-pin connectors from and to my audio interface) some of the controls react weirdly on the device itself. for example the panning in the mixer section is pretty much un-editable with the encoder. values go down and make big jumps whatever direction I turn. still works as it should when I control it from the editor though. its not the encoders because other parameters work perfectly with that same encoder. only noticed it on the pan controls and the filter cutoff so far. the cutoff works better though, I just get skips occasionaly. The oddest part is, when I close ableton, all the parameters and encoders work perfectly again. so it might be some kind of midi going back and forth and causing these weird jumps. I have no idea why though...

Did anyone run into similar problems and has some tips? hope I could explain it well
as there are workarounds for this, it's not that big of a deal. still a bit frustrating...

thanks in advance,

Marc
93
PreenFM2 / Re: Inconsistent sound with certain algorithms
« Last post by cwyss on October 03, 2018, 07:21:48 PM »
Ok, I think I found it:
it's the envelope release time settings of the operators that cause the problem.

Instability occurs in two different cases:
  • All carrier envelope release times are 0.00. This gives a strong instability.
  • The release time of one carrier is smaller than the release time of its modulator. Here the instability is more subtle, but can be observed with a spectrum analyser. Also: the greater the difference of the release times, the greater the effect.
The amount of instability also depends on the carrier to modulator frequency ratio c:m; you get a strong effect for c:m=1:2, for example.

Here is a list of steps to reproduce these instability phenomena:
Start with the patch "Preen mk2" from the factory default combo. It uses alg9. Then make the following parameter changes:
  • op1,op6 off
  • op4: sine, freq=1.00
  • op5: sine, freq=2.00
  • for op4 and op5: env attk, deca, sust time=0.00, level=1.00
  • Matrix 2: mult=0.00 (this has the routing lfo1->pan2)
  • Matrix 12: mult=0.00 (this is Not1->IM*)
This produces a steady timbre with stable frequency spectrum between repeated key strokes.

Now set
  • op1, op4 and op5 rele time=0.00
You get an instability of the first type, which is easily audible (at least for me ;) ). Then:
  • op1 rele time=2.56
It's stable again. Then
  • op4 rele time=0.50
  • op5 rele time=1.50
This is the instability of the second type. Finally
  • op5 rele time=0.25
Again stable.

I tested this by repeatedly playing a C at 261Hz. In my spectrum analyser I then measured the level difference between the 1. and 3. harmonic, i.e. at 261Hz and 785Hz.
In the stable case I obtain a difference of around 11dB, where the 3. harmonic is stronger. For the first type of instability the changes are drastic, sometimes the 1. harmonic even becomes strongest. For the second type, the measurements vary between 11dB and around 8dB, if I remeber correctly.
For the second type, the time you wait befor the next key stroke also seems to matter. If I release the key, then wait for the sound to die completely, and only then trigger the note again, then the instability is much smaller. If after key release I retrigger the note immediately, the instability is stronger.
It seems like you have to give the envelopes enough time to complete their release phase...

Finally I also checked some other algorithms and got the same results:
for alg11 (with both cascades 123 and 456), alg14 (cascade 123), alg16 (345), alg1 (123)

My conclusion (so far):
  • Avoid setting all release times of your carriers to 0.00. It is sufficient to have one >0.00, and this one can even be turned off(!). However a very small time like 0.01 might not be enough.
  • The second type of instability is hardly audible (I was not able to hear it), so I guess one can live with it... Unless we aim to verify FM theory and Bessel function values by measuring the output of the preenfm ;)
  • These instabilities remind me of the tuning instabilities of the pre-DCO analog synths of the 70s, and the efforts in virtual analogs to recreate those free-running and drifting oscillators. In order to accurately capture the warmth and character attributed to the vintage synths. So in the end we also might want to preserve this analogish "character" of our little machine... ;)
94
PreenFM2 / Re: Inconsistent sound with certain algorithms
« Last post by cwyss on October 02, 2018, 08:50:50 AM »
So yesterday I did some more knob tweaking and button pushing and finally arrived at a patch with the setup I intended and which is now perfectly stable.   :D

This one uses algo 9 with op1 and op6 off, op4 and op5 are sine with freq=1.00 and the IM from op5 to op4 is 2.00. The envelope settings for op4 and 5 are again gate-type, as in my first patch. Also velocity and voices settings are the same.

So with my first patch perhaps I found some strange "instable" combination of parameters?
Will do some more testing and then report.
95
PreenFM2 / Inconsistent sound with certain algorithms [Fixed in 2.09]
« Last post by cwyss on September 30, 2018, 01:53:41 PM »
Hi!

When I use  algorithms with stacked modulators, e.g. alg1, alg5 or alg11 which all contain the chain Op3->Op2->Op1, I experience a random change in the tone colour between consecutive strokes of the same key.

My patch is very simple:
  • Start e.g. with alg1, velo=0, voice=6
  • set op1 and 2 to sin, keyb, freq=1.00, ftun=0.00; op3=off
  • set a "gate profile" for op1 and op2 envelopes, i.e. lv=1.00 for Attk,Deca,Sust, Release lv=0.00, all times=0.00
  • all matrix routing off (I used srce=none)
  • Modulation IM1=2.00, v=0.00, all other modulation off
  • arp and filter both off
If I now play a note, I get a slightly different tone everytime I press a key. I see this in a spectrum analyser where most of the time the amplitude of the carrier frequency is smaller than that of the first sideband c+m (and even the second c+2m), but sometimes also the carrier is the strongest component. This changes in tone colour are also audible.

I get the same behaviour with different algos, as long as they contain op2->op1 and op2 is the destination of another operator, e.g. alg5 or alg11.

To be absolutely clear here: When I play and hold a single note, this one note is perfectly stable, no change in its spectrum at all.
But when I release the key and then hit it again, then I obtain a different spectrum than before. The change is sometimes smaller, sometimes larger, in an apparently random way.

At first I thought perhaps this is how FM works in this particular situation, but...:
  • Since my patch use only two ops, I went to alg3 where op2 is not the destination of another modulator and voilà: no more change in spectrum, everything is perfectly stable! The same for other algos with op2->op1 and op2 not destination of some other op
  • When I stay with alg1 and now turn on op3=sin, keyb, freq=2.00, ftun=0, op3 env="gate" as for op1 and op2, and IM2=1.00. Then I also get a changing spectrum as described above. (Only this time perhaps the differences are bigger) Again the situation is identical for alg5 or alg11.

So this is probably a bug?
96
PreenFM2 / Default combo does not respect release time setting [Fixed in 2.09]
« Last post by cwyss on September 30, 2018, 10:19:18 AM »
Hi!

I noticed that when the default combo is loaded at boot time, the release time parameter of Instrument 1, Operator 1 is not affected. It always starts at a value of 2.56 after boot.

My goal was to have a kind of clean init patch after boot with just a pure sine wave and simple gate for all envelopes, i.e.,

Attk lv   Deca lv   Sust lv   Rele lv     
0.00 1.00 0.00 1.00 0.00 1.00 0.00 0.00


But when I make these setting, do menu->Save->Defl->Save, and then reboot, the release time is again at 2.56. All other params are loaded ok from the defl combo.
97
PreenFM2 / Re: General praise
« Last post by cwyss on September 30, 2018, 09:58:26 AM »
Also big cheer from my side!

I have build mine only a week ago and am just starting to explore FM land.
But I'm already quite exited  ;D

One thing I really like about it is that it is so small and light, but at the same
time so easy to edit thanks to the 4 encoders and the design of the menu system.

Already for some time I had been searching for a nice little, portable synth module,
one serious candidate being the D-05 from Roland. But then I stumbled about this
article on vintagesynth.com
http://www.vintagesynth.com/articles/5-synthesizers-do-it-yourself-enthusiasts
and couldn't resist the combination of DIY, portability and FM.

Awesome machine, thanks Xavier!!!
98
PreenFM2 / Re: General praise
« Last post by eeliyx on September 28, 2018, 10:09:48 PM »
Just wanted to chime in here because I finished my build last week.
Thanks for you hard work, Xavier!
It was my first DIY synth and only the second time doing any soldering but everything went perfect.
99
PreenFM2 / Re: Preenfm2 make no sound
« Last post by Xavier on September 27, 2018, 04:14:18 PM »
Hi,

I think you can try by reading this thread :
http://ixox.fr/forum/index.php?topic=63509.0
And having a look a the schema in Reply#6 to double check all the soldering junction of the audio path.

Xavier
100
PreenFM2 / Preenfm2 make no sound [Resolved]
« Last post by imac27 on September 25, 2018, 10:09:20 PM »
iìve just assembled a kit buyed from tubeohm and i follow the build instruction, it's perfect but no audio coming from output. how can i resolve. i'm going crazy  :'(

P.s. sorry for my english
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